Next-Generation Bioinputs: A Systematic Review of Biosurfactants in Sustainable Agriculture and Research Frontiers with Bacterial Cellulose

Abstract

This systematic review article provides a comprehensive and critical analysis of the use of bioinputs in sustainable agriculture, focusing on biosurfactants and absorbent polymers, particularly bacterial cellulose. The article contextualises the growing challenges in agricultural production due to population growth, climate change, and environmental limitations, highlighting the need for alternatives to traditional synthetic inputs that exert negative environmental impacts. The article details functions, types, and benefits, emphasising the ability of bioinputs to improve soil fertility, increase the efficiency of nutrient use, enhance plant resistance to biotic and abiotic stress, and reduce the ecological footprint of agriculture. Emerging biotechnologies are discussed, such as the combined use of biosurfactants with natural polymers to ensure sustainability and efficiency. This article offers an updated description of recent scientific and technological evidence and addresses the potential and limitations of these biological inputs in the global context of modern agriculture.

1. Introduction

The continuous growth of the world population, combined with urbanisation and changes in dietary patterns, has intensified pressure on agricultural systems to increase food production under conditions of natural resource scarcity. Projections indicate a significant rise in global food demand by 2050, exacerbating challenges such as soil degradation, desertification, water scarcity, and environmental impacts associated with conventional agricultural expansion [1,2,3]. These challenges are closely aligned with the Sustainable Development Goals (SDGs), which emphasise resilient agricultural systems with reduced environmental impact, focused on food security, water conservation, and ecosystem restoration [4].

Agriculture accounts for approximately 70% of global freshwater consumption, and inefficient management practices, pollution, and soil degradation contribute to water losses, reduced productivity, and increased vulnerability to climate change [5,6]. In response, biotechnological innovations and the use of bioinputs have emerged as strategic approaches to reconcile agricultural productivity with environmental sustainability, particularly in restrictive environments [2,7].

Conventional agriculture has long depended on synthetic fertilisers and chemical pesticides to sustain productivity. However, the intensive use of these inputs has led to soil and water contamination, biodiversity loss, pest resistance, and risks to human health [8]. The global dependence on phosphorus-, nitrogen-, and potassium-based fertilisers concentrated in a small number supply chains also exposes the agricultural sector to geopolitical shocks and market instabilities [9,10].

With the exhaustion of this model, there is a growing interest in regenerative practices and the adoption of bioinputs capable of restoring soils, diversifying productive sources, and increasing the resilience of agroecosystems [9]. These biological products derived from biological agents, such as secondary metabolites and functional biomolecules, as well as the use of beneficial microorganisms, can replace or reduce the use of conventional chemicals, promoting natural cycles of soil nutrition, protection, and regeneration [11,12]. Evidence indicates that bioinputs improve nutrient use efficiency, increase tolerance to environmental stress, enhance productivity, and reduce the ecological footprint of agriculture, motivating investments in regulatory frameworks and public policies to support their adoption [13,14,15,16].

Despite recent advances, challenges related to standardisation, quality control, and technology transfer limit the broader adoption of bioinputs. The absence of harmonised testing conditions for water absorption and retention, combined with the reduced performance of many bio-based superabsorbents under saline, alkaline, and mechanically loaded soil conditions, hampers reliable performance comparison and formulation optimisation. In the context of water stress, the use of absorbent polymers (APs) has been effective in the retention of moisture and the optimisation of irrigation, providing greater root hydration, better seedling development, and a reduction in the leaching of nutrients [17]. However, concerns about persistent residues and the low biodegradability of synthetic APs have stimulated the development of natural biopolymers, such as hydrogels of a microbial and plant origin aligned with the principles of the circular economy [18,19].

Among these alternatives, biosurfactants (BSs) and bacterial cellulose (BC) stand out as promising biomolecules. BSs are surface-active compounds of biological origin produced by microorganisms such as bacteria, fungi, and algae. These amphiphilic molecules consist of a hydrophilic moiety, composed of amino acids, peptides, or mono-, di-, or polysaccharides and a hydrophobic moiety mainly formed by saturated or unsaturated fatty acids, which enables their interfacial activity. Due to their biodegradability and low toxicity, BSs have been applied in agriculture to enhance nutrient bioavailability, promote soil remediation, control phytopathogens, and stimulate plant growth [20,21,22,23,24,25,26,27]. BC is a high-purity biopolymer with notable mechanical strength and water retention capacity and can be produced from agro-industrial residues, reducing costs and environmental impacts [28]. Although BC lacks intrinsic antimicrobial activity, its structure allows functionalisation with active compounds, broadening its agricultural applications [29,30].

Recent studies indicate that the combined use of BSs and BC in hybrid matrices, controlled-release systems, and nanoformulations can enhance agronomic efficiency and support sustainable production systems [31,32,33]. Accordingly, this review critically analyses recent advances in the application of synthetic and natural surfactants and absorbent polymers in agriculture, highlighting bacterial cellulose as an alternative to synthetic polymers and the role of biosurfactants in soil improvement, environmental impact mitigation, and the development of resilient agroecosystems. Figure 1 schematically summarises the transition from conventional to sustainable agricultural systems.

2. Methods

This systematic review was conducted in accordance with the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA 2020 protocol), ensuring transparency, traceability, and reproducibility in all phases of the study [34,35]. The steps of identification, screening, eligibility and inclusion of studies are shown in the flowchart in Figure 2, created based on the criteria defined in this study.

2.1. Identification Step

The main timeframe comprised the period from 2021 to 2025 in order to capture the most recent representative publications on the topic.

For patent databases and technological platforms, however, the timeframe was extended to the period from 2010 to 2025 due to the scarcity of relevant results in the initial period, resulting in 39 records, 20 of which were maintained for directly relating to the application of biosurfactants as inputs or active agents in agriculture.

A systematic search was performed in the Scopus and Web of Science databases, complemented by additional queries in Google Patents, WIPO, Lens.org, and SpaceNet (indicated in the flowchart as “others”). These patent platforms were specifically chosen to provide extensive international coverage of technological advancements, including major patent offices like USPTO and EPO.

The main timeframe for scientific publications comprised the period from 2021 to 2025. For patent databases, the timeframe was extended to 2010–2025 because of the limited number of relevant patent documents found in the initial period. This change led to the identification of 39 patent records, with 20 of them being retained for directly addressing agricultural applications of biosurfactants or microbial biopolymers.

The search string was created with Boolean operators and truncation: (biosurfactant OR rhamnolipid OR sophorolipid OR lipopeptide OR “bacterial cellulose”) AND (agricultur* OR pesticide OR fungicide OR biostimulant OR “soil enhancement” OR “plant growth”) AND NOT (petroleum OR cosmetic OR pharmaceutical OR drug OR food OR fuel OR lubricant OR “oil recovery” OR “enhanced oil recovery” OR “crude oil” OR diesel OR gasoline OR “personal care” OR shampoo OR “skin care” OR medical OR “wound healing” OR “food emulsifier” OR “food additive” OR emulsion OR “food processing” OR dairy OR bakery OR beverage).

For patent searches, this strategy was adapted to account for differences in indexing terms and classification systems.

2.2. Screening Step

A total of 1592 records were identified (Scopus: 1374; Web of Science: 179; Others: 39). Thirty duplicate records were removed using Mendeley Reference Manager (version 2.138.0), leaving 1562 records for screening. The screening process was conducted by the authors, who independently evaluated titles and abstracts based on predefined inclusion and exclusion criteria. Any disagreements were resolved through discussion until a consensus was reached. Titles and abstracts were analysed based on the following inclusion criteria: (i) focus on biosurfactants or bacterial biopolymers; (ii) agricultural or agro-industrial applications; (iii) publication type (original articles, reviews, or book chapters); (iv) English language; and (v) open-access availability. Only studies published in English were considered to ensure consistency in data interpretation, reproducibility of the screening process, and alignment with international standards commonly adopted in systematic reviews. A total of 733 records were excluded for not meeting these criteria, either because of being related to other fields of application (cosmetics, pharmaceuticals, food, or petrochemicals), addressing aspects not directly related to sustainable agriculture, or not having the full text available.

2.3. Eligibility Step

Among the 829 full texts analysed, 596 were excluded for not addressing the topic of interest (e.g., use of biosurfactants in non-agricultural contexts), the absence of clear methodological or experimental information, having insufficient results to support relevant conclusions, duplicity of content or overlap with studies already included, and inconsistency in the data or absence of a correlation between the methods and results.

2.4. Inclusion Step

After all steps, 233 studies were included in the final review. These studies include publications that address the use of biosurfactants and microbial biopolymers, including bacterial cellulose, for sustainable agricultural applications, whether as biostimulants, biological control agents, promoters of plant growth, or components of innovative agro-industrial formulations.

2.5. Data Extraction and Analysis

Data extraction was conducted manually using structured spreadsheets, recording information on authorship and year of publication, type of compound or microorganism studied, objectives, methods employed, main results, and potential agricultural applications. Data analysis was qualitative and categorical because of the high variability among the studies, which included differences in experimental designs, evaluation methods, performance indicators, and agricultural application contexts. This variability limits direct quantitative comparison and statistical pooling. Although partial quantification (such as reporting frequencies or performance ranges) is possible, conducting a fully quantitative or meta-analytical approach was not feasible without risking bias or oversimplification. Data analysis enabled the identification of emerging technological trends, gaps in knowledge, and opportunities for innovation. The final synthesis was organised to highlight the main scientific and technological contributions related to the use of biosurfactants and bacterial biopolymers in sustainable agriculture, as well as prospects for industrial and biotechnological applications.

3. Agricultural Inputs: Classification and Impacts

Population growth and changes in consumption patterns have intensified pressure on agri-food systems, requiring significant increases in productivity to meet future food demand. Since the 1960s, agricultural intensification driven by the widespread use of external inputs—such as synthetic fertilisers, pesticides, stimulants, and adjuvants—has played a central role in increasing global food production and ensuring supply stability [36,37,38,39,40,41,42]. These inputs have become key determinants of land-use efficiency, economic performance, and food security.

Agricultural inputs are defined as external resources incorporated into production systems to enhance nutrient availability, protect crops against biotic and abiotic stresses, and optimise plant physiological processes, thereby improving agronomic efficiency and economic returns [43]. Traditionally, these inputs are classified into four main groups—fertilisers, pesticides, stimulants, and adjuvants—which together constitute the technological foundation of intensive agriculture [44,45,46].

Despite their contribution to productivity, the intensive and often inefficient use of conventional agricultural inputs has generated significant environmental and socioeconomic challenges. These include nutrient leaching and eutrophication, soil and water contamination by pesticides and heavy metals, greenhouse gas emissions, soil acidification and salinisation, loss of soil biodiversity, and the emergence of resistant pests and pathogens [47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85]. Such impacts highlight the need for rational input management, technological innovation, and the adoption of more sustainable alternatives aligned with the Sustainable Development Goals (SDGs) [86,87,88,89,90,91].

Table 1. Traditional agricultural inputs used in conventional agriculture [45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85].

Input Category	Main Function	Common Examples	Key Characteristics	Main Environmental Concerns
Fertilizes	Supply essential nutrients for plant growth	Urea, ammonium nitrate, superphosphate, potassium chloride, NPK formulations	High solubility; rapid nutrient availability; high dependence on industrial production	Nutrient leaching, eutrophication, soil acidification, greenhouse gas emissions
Pesticides	Control pests, diseases, and weeds	Herbicides (glyphosate, atrazine), insecticides (organophosphates, pyrethroids), fungicides (triazoles), rodenticides	High specificity and effectiveness; chemical persistence varies by class	Toxicity to non-target organisms, bioaccumulation, resistance development, environmental contamination
Stimulants	Modulate plant physiological processes and stress responses	Humic and fulvic acids, protein hydrolysates, seaweed extracts, chitosan	Improve metabolic efficiency and stress tolerance; applied at low doses	Variable efficacy; limited standardization
Adjuvants	Enhance the performance of agrochemical applications	Surfactants, oils, wetting agents, drift reducers, pH buffers	Improve spray spreading, adhesion, and absorption	Potential ecotoxicity depending on chemical composition

summarises the principal traditional inputs used in conventional agriculture and

Table 2. Main challenges associated with use of agricultural inputs.

Problem	Technical Description	Consequences	Refs.
Leaching of nutrients (N and P)	Downward movement of nitrates and phosphates in soil, surpassing the root zone due to high solubility and precipitation or excessive irrigation	Contamination of groundwater; eutrophication of water bodies; reduction in efficiency of nutrient use	[92,93]
Emission of greenhouse gasses (N2O, CH4, CO2)	Emissions resulting from microbial processes in the soil (nitrification and denitrification), enteric digestion, fermentation of residues, and use of nitrogenated synthetic fertilisers	Significant contribution to global warming; changes in climate patterns; impact on food security and ecosystems	[94,95,96]
Contamination by pesticides	Intensive application and persistence of synthetic pesticides (organochlorides, organophosphates, carbamates), transport by leaching, volatilisation, and surface runoff, with formation of more persistent toxic metabolites	Contamination of soil, surface waters, and groundwater; diffuse pollution; bioaccumulation in food chains; impacts on biodiversity; risks to human health (toxicity, carcinogenicity)	[97,98,99]
Bioaccumulation of heavy metals	Presence of toxic metals (Cd, Pb, Cr, As) in phosphate fertilisers and agricultural inputs, with mobility and persistence in soil	Contamination of soil and water; transference to food chains; risks to human health and ecosystems	[10,100]
Resistance of pests and pathogens	Evolutional adaptation via mutation, hybridisation, or genetic transference, enhanced by continual use of synthetic pesticides	Loss of effectiveness of defensives; increase in selective pressures; need for larger doses; ecological imbalance; risk to food security	[101,102,103]
Acidification of soil	Reduction in pH and loss of buffering capacity of soil accelerated by excessive use of nitrogenated fertilisers, which promote nitrification, release of H+, and leaching of basic cations	Nutritional imbalance, reduction in fertility and agricultural productivity, increase in greenhouse gases	[104,105,106]
Salinisation	Accumulation of soluble salts in soil matrix resulting from high evapotranspiration, excessive irrigation, deficient drainage, saline intrusion, and intensive use of fertilisers	Reduction in fertility of soil; water restriction; ionic toxicity; drop in agricultural productivity; environmental degradation; threat to food security	[107,108,109]
Loss of biodiversity of soil	Reduction in microbial diversity and soil fauna due to intensive use of pesticides, climate change, and degradation of soil	Impairment of nutrients cycling, reduction in fertility, lower resilience of ecosystem, increase in vulnerability to climate change, and risks to food security	[110,111]
Diffuse pollution and eutrophication	Loss of nutrients (N and P) due to leaching and surface runoff associated with intensive use of fertilisers and inadequate farming practices, promoting enrichment of water bodies	Formation of hypoxic zones; loss of aquatic biodiversity	[112,113,114,115]
Emerging pollutants (microplastics and POPs)	Microplastics derived from degradation of agricultural polymers and plastic waste capable of adsorbing plastics (POPs, heavy metals); POPs are halogenated lipophilic compounds of high persistence and low degradability	Change in structure of soil, reduction in fertility, transport of contaminants, contamination of water and food chains, bioaccumulation, and risks to human health	[116,117,118,119,120]

summarises the main problems associated with the use of agricultural inputs, describing technical aspects, consequences, and references.

4. Bioinputs: Definition, Types, and Biochemical Nature

Agricultural bioinputs are products developed from microorganisms, plant extracts, crustacean shells, and other materials of a biological origin that can replace or complement chemical inputs in a sustainable way. The use of this technology has grown because it enables an increase of agricultural productivity combined with environmental preservation. Agricultural bioinputs not only reduce dependence on chemicals but also strengthen the resilience of production systems and contribute to more balanced, sustainable agricultural practices [121,122].

The effects of bioinputs on soil and plant development are widely recognised for the ability to improve soil structure, increase water and nutrient retention, and favour the growth of healthier, more resilient plants. Figure 3 compares the performance of agricultural systems with and without the application of bioinputs, showing the agronomic and environmental benefits.

Depending on the application, bioinputs are classified as agricultural defensives, biofertilisers, and biostimulants.

4.1. Biological Defensives

Unlike chemical pesticides, which act by toxic effects, biological defensives exploit biological mechanisms, such as competition, parasitism, or the production of metabolites that inhibit the development of unwanted organisms [123]. Although chemical pesticides remain the most widely used globally due to their rapid action and wide commercial availability, biological defensives have been gaining prominence in recent decades. This growth is due to the increasing demand for sustainable agricultural systems, the international restriction on the use of highly toxic molecules, and the advancement of production and formulation technologies [121,123,124].

Among the main advantages of biological pesticides are greater specificity to the target organism, prolonged control, biodegradability, low toxicity to humans and non-target organisms, compatibility with integrated pest management strategies, and the potential to reduce costs in the medium term due to lower dependence on chemical inputs [123,124]. Depending on the mode of action or type of biological agent employed, biological pesticides are classified as agents of parasitism, predation, entomopathogens, bioherbicides, biofungicides, biopesticides, or bionematicides.

With parasitism, as in the use of parasitoid wasps (Hymenoptera), natural enemies lay their eggs inside the eggs or larvae of insect pests, leading to the death of the host during embryonic development. Recent strategies demonstrate that the association of parasitoids with nanopesticides increases efficiency in aphid control by maintaining the survival of natural enemies in the field [123].

Control by predation involves organisms such as birds, ladybugs, or lacewings that feed directly on pests. This is a traditional strategy in agroforestry and organic systems that has been improved with the selection of more efficient species for intensive crops [124].

Entomopathogens, especially fungi such as Metarhizium anisopliae and Beauveria bassiana and bacteria such as Bacillus thuringiensis, act by infecting and killing insects, achieving excellent results. An example of this is the efficiency of Aspergillus nidulans in the control of Alternaria alternata [121]. There is also growing interest in the formulation of mixtures of biological agents combined with emerging technologies, such as nanoparticles and biodegradable polymers capable of expanding the spectrum of action and enhancing the stability of products [125].

In weed management, bioherbicides are developed from microorganisms, such as Trichoderma koningiopsis, or plant extracts, such as the essential oil from Aniba canelilla, and are capable of inhibiting the germination of Eragrostis plana at concentrations lower than 0.05% [126]. Agro-industrial waste, such as orange peels or shrimp shells, have also been used as a substrate for fermented formulations with herbicidal potential, aggregating value to byproducts and incorporating principles of the circular economy [127].

Biofungicides intended for the control of fungal diseases such as rot, downy mildew, and powdery mildew, use non-pathogenic microorganisms that compete for space and nutrients or produce antimicrobial metabolites. An example is the seed extract from Moringa peregrina, which has potent activity against Mycogone perniciosa, proving to be a viable alternative to synthetic fungicides [128].

Biopesticides are widely studied due to the economic importance of insecticides and include bacterial, viral, or botanical formulations. Among recent contributions, a culture medium based on Opuntia ficus-indica and seawater was developed for the production of endotoxins by Bacillus thuringiensis israelensis, which surpassed the effectiveness of the commercial product VectoBac in the control of mosquito vectors in North Africa [129]. Technologies such as the nanoencapsulation of the essential oil from Piper aduncum in zein nanoparticles have also shown promise for increasing efficiency against Spodoptera frugiperda and reducing phytotoxic effects on cultivated plants [125].

Bionematicides for the management of plant-parasitic nematodes constitute a rapidly expanding segment due to the damage that these organisms cause, especially Meloidogyne spp., which is responsible for up to 80% of occurrences [130]. Recent studies with Bacillus spp. isolates from the soybean rhizosphere promoted up to 90% immobility of juveniles (J2) of Meloidogyne enterolobii. Similarly, Trichoderma harzianum (isolates ALL42 and IBFL006) has demonstrated similar potential in banana plants, significantly reducing the nematode population in the roots and stimulating natural defence mechanisms [131,132].

4.2. Biofertilisers

Biofertilisers contribute to soil enrichment and the availability of nutrients to plants, improving fertility, favouring biological nitrogen fixation, and stimulating beneficial microbial activity in the soil. Although the development of biofertilisers dates back to the early twentieth century with the first bacterial inoculants for legumes, their use has gained global relevance in recent decades, driven by environmental constraints, biotechnological advances, and recent crises in the supply of mineral fertilisers [122,133].

Beginning in 2022, the instability caused by the conflict between Russia and Ukraine has highlighted the dependence of major agricultural powers, such as Brazil, the United States, China, and India, on the import of nitrogen, phosphate, and potassium fertilisers, mainly from Russia, Canada, and countries of the North Sea. Supply shortages and rising prices have exposed vulnerabilities in global chains and catalysed interest in renewable local alternatives [134].

Compared to conventional chemical fertilisers, biofertilisers have multiple agronomic and environmental advantages: they derive largely from agro-industrial waste or low-cost renewable biomass, have low toxicity, promote the gradual release of nutrients, improve the structure of the soil, and reduce losses due to leaching. Moreover, many have indirect mechanisms that promote plant growth, such as nutrient solubilisation, phytohormone production, the induction of systemic resistance, or antagonism to phytopathogens [122]. These characteristics contribute to greater efficiency in the use of nutrients and a reduction in the carbon footprint of agriculture, meeting the demand for more resilient, regenerative production systems.

Recent studies have demonstrated rapid scientific advancement in the field. For instance, micro- and macroalgae are used as sources of bioactive compounds and essential nutrients, such as N, P and K, whose extracts can be applied to soil or leaves, promoting greater biological nitrogen fixation and stimulating plant growth [135]. Beneficial microorganisms, including nitrogen-fixing (diazotroph), phosphate-solubilising, and growth-promoting bacteria, have demonstrated considerable efficiency under conditions of high pH or saline, contributing to the adaptation of crops to increasing abiotic stress [136,137].

Arbuscular mycorrhizal fungi have also been widely investigated for their ability to expand the volume explored by roots, increasing the absorption of nutrients with little mobility, such as phosphorus and zinc, in addition to enhancing tolerance to drought, which makes these fungi strategic in semiarid regions [138,139].

4.3. Biostimulants

The main function of biostimulants is to induce physiological responses in plants, promoting greater tolerance to abiotic stress, such as drought, salinity, and changes in temperature, in addition to improving vigour, productivity, and the final quality of the crop [140]. Scientific interest in biostimulants has grown substantially in recent years, reflecting the recognition of the importance of these substances in terms of resilience to climate change [141].

In modern agricultural systems, productivity is conditioned by controllable factors, such as pests, diseases, and nutritional management, as well as unpredictable factors, such as drought, heavy rainfall, and extreme changes in temperature. Biostimulants serve as strategic allies favouring physiological responses that enhance the tolerance of plants to adverse conditions and optimise efficiency in the use of water and nutrients, thus contributing to the stability and sustainability of crops [142]. As these substances have low toxicity, high biodegradability, and a low degree of leaching, and enable the gradual release of active compounds often derived from low-cost raw materials, biostimulants have aroused growing interest among farmers and agribusiness companies [139].

A fundamental aspect of biostimulants is interaction with the rhizosphere, which is the zone of the soil that surrounds the roots and where intense biochemical exchanges take place among the soil, plants, and associated microbiota. The rhizosphere is recognised as the main setting for the modulation of plant growth and health, as it concentrates beneficial microorganisms capable of directly influencing nutrient absorption and resistance to environmental stress. The application of biostimulants in this region can improve the quality and activity of this microbiota, promoting the gradual release of nutrients and stimulating biochemical processes that favour root development and soil health [143]. This synergic interaction strengthens the ability of plants to exploit the soil more efficiently, resulting in greater productivity and resilience.

Biostimulants have diverse origins, such as macro- and microalgae, plant extracts, protein hydrolysates, humic compounds, free amino acids, chitin, and growth-promoting microorganisms. Seaweed extracts, for instance, have demonstrated effectiveness in promoting tolerance to salt stress in maize [141], stimulating shoot and root growth of arugula [144] and increasing the productivity and quality of organic strawberries [142]. The combination of tropical plant extracts and legume protein hydrolysates has also shown promise in cherry tomatoes grown in soilless systems, serving as a multifunctional growth agent [140]. From a microbial standpoint, plant growth-promoting rhizobacteria, such as strains of Azospirillum, Pseudomonas, and Bacillus, are widely investigated for the ability to increase nutrient absorption, synthesise phytohormones (auxins, cytokinins, and gibberellins), and modulate antioxidant responses in plants under water or salt stress [143].

5. Biosurfactants: Multifunctional Alternatives

Biosurfactants are natural amphiphilic molecules, with the simultaneous occurrence of hydrophilic (polar) and hydrophobic (nonpolar) portions. This structural characteristic gives such compounds the ability to reduce the surface tension of water and promote the formation of stable emulsions between immiscible liquids, such as oil and water. In addition to their functionality, BSs stand out for their biodegradability, production from renewable sources and/or industrial waste, low toxicity, and stability in wide ranges of pH, temperature, and salinity. Antimicrobial properties have also been reported, which further expand the application potential of these natural compounds [145].

BSs have demonstrated multiple functions in promoting plant growth, the solubilisation of nutrients that are not available in the soil, the simulation of physiological processes associated with root development, and a significant increase in the tolerance of plants to oxidative, thermal, and saline stress. BSs also contribute to the improvement of the physical structure of the rhizosphere, favouring the mobilisation and availability of essential nutrients and increasing the efficiency of the root system and biodefensive activity [146,147,148].

In contrast, synthetic surfactants (petroleum derivatives), although widely used in agricultural formulations as emulsifiers, plasticisers, active adjuvants, herbicides, fungicides, and insecticides, have significant environmental disadvantages. These compounds often have high toxicity, low biodegradability, and can persist in the environment, posing risks to health and ecosystems [149].

BSs can be obtained from plant extracts (plants, roots, and fruits) and via microbial metabolism involving bacteria, fungi, and yeasts [150]. Among these sources, microbial biosurfactants are the most studied due to their high productivity, ease of cultivation, and greater functional similarity with chemical surfactants. These natural surfactants have been used in various industries, such as household cleaning supplies, cosmetics, textiles, food, agriculture, and environmental remediation [145].

A fundamental concept related to the efficiency of BSs is the critical micelle concentration (CMC), which is the minimum concentration of biosurfactant required to form micelles in the solution. Until the CMC is reached, the increase in the BS concentration results in a further reduction in surface tension. However, once this point is surpassed, the surface tension stabilises and the additional biosurfactant is organised into micelles or other supramolecular structures [149]. The CMC is therefore indicative of the efficiency of a BS, as a lower value indicated greater efficiency in reducing surface tension with lower amounts of the compound (see Figure 4).

5.1. Biosurfactants: Classification and Applications in Agriculture

BSs are classified according to chemical structure and microbial origin. The main classes are glycolipids, lipopeptides, phospholipids, fatty acids, polymeric biosurfactants, and particulates. Low molar mass compounds, such as glycolipids, lipopeptides, and phospholipids, are generally effective at reducing air-water surface tension. On the other hand, high molar mass BSs, such as lipoproteins, proteins, polysaccharides, and lipopolysaccharides, tend to act as emulsifying agents due to the more complex structure [149,150,151]. Among the different classes, glycolipids are the most widely investigated and contain a carbohydrate fraction in their structure. Examples include rhamnolipids, sophorolipids, trehalolipids, and mannosylerythritol lipids.

Rhamnolipids are a subclass of glycolipids that have been widely studied due to their structure, which is formed by one or two rhamnose units linked to fatty acids, and their potential for application in different industries. The synthesis of these compounds is modulated by the microbial strain, carbon source, and cultivation conditions. Pseudomonas aeruginosa is the most investigated rhamnolipid-producing species and widely reported in the literature for its high biosynthesis capacity. The main advantages include the possibility of production from renewable waste and high efficiency in reducing surface tension (from 72 to ~30 mN/m) and interfacial tension (from 43 to ~1 mN/m), in addition to CMC values ranging from 50 to 200 mg/L, depending on the chemical composition [152,153].

Rhamnolipids have diverse applications in the agricultural context, including use as pesticides, bionematicide agents, and promoters of plant growth [146,154]. Moreover, structural variants have different functions; while mono-rhamnolipids are more often associated with the biological control of phytopathogens and nematodes [155,156], di-rhamnolipids correlate with the promotion of plant growth, favouring nutrient absorption and enhanced tolerance to abiotic stress [157]. This structural diversity demonstrates the multifunctional potential of rhamnolipids and their relevance to strategies aimed at sustainable agriculture.

Sophorolipids are biosurfactants produced mainly by yeasts, especially Starmerella bombicola (teleomorph of Candida), which is widely recognised in the literature as one of the most efficient species in terms of synthesis [158]. Structurally, sophorolipids are composed of a sophorose joined to fatty acids by glycosidic bonding, with the ability to reduce surface tension to around 33 mN/m and interfacial tension to approximately 5 mN/m. The main advantages include high fermentation productivity, with yields that can exceed 300 g/L [159,160,161], and broad antimicrobial activity, which makes sophorolipids promising compounds in the control of phytopathogens in different agricultural systems [147,162]. Recent studies indicate that, at lower concentrations, sophorolipids can serve as biostimulants, favouring plant growth and enhancing resilience to adverse conditions [146,147]. This combination of high production efficiency, functional versatility, and low environmental impact demonstrates the potential of sophorolipids as viable alternatives to conventional chemical inputs in sustainable agriculture.

Trehalolipids, also known as trehalose lipids, are a subclass of glycolipids whose structure is based on trehalose disaccharides bound to mycolic acids, with high structural diversity. These compounds are produced by both plants and microorganisms, including genera such as Rhodococcus, Mycobacterium, and Corynebacterium, and have the ability to reduce surface tension to 25–40 mN/m and interfacial tension to 1–5 mN/m [159,163]. Although their potential is little explored in the agricultural context, evidence indicates that high concentrations of trehalose are associated with increased plant resistance to different types of abiotic stress [164]. Recent trials involving the application of trehalolipids to seeds prior to sowing and leaf treatments have shown promising results, including greater tolerance to saline soils and increased nutrient uptake [154]. These findings reinforce the relevance of trehalolipids as candidates for bioinputs in sustainable agricultural systems.

Mannosyleryteritol lipids (MELs) are biosurfactants produced mainly by microorganisms of the genus Pseudozyma, especially Pseudozyma antarctica, from vegetable oils. Structurally, MELs are composed of a mannose unit linked to a fatty acid. Variations result from the length and degree of saturation of the lipid chain as well as the level of acetylation of the sugar [165]. The literature reports the functional properties of MELs, including emulsifying activity, surfactant action, and potential anticoagulant effects [166]. However, use in the agricultural context is incipient and poorly documented; in many cases, no details are given about the microbiological origin of the compound. Despite these limitations, studies indicate that low concentrations of MELs can serve as biostimulants, promoting positive effects on plant growth, while higher concentrations have an inhibitory effect, suggesting strategic use as bioherbicides [148]. This multifunctionality demonstrates the potential of MELs and underscores the need for further studies to clarify the mechanisms of action and expand applications in sustainable agricultural systems.

BSs with high molar mass include lipopeptides, phospholipids, and polymeric compounds, traditionally applied in emulsion formation and stabilisation processes. Surfactin is a cyclic lipopeptide produced by Bacillus subtilis composed of a long lipid chain (13–15 carbons) and several amino acids (Asn, Leu, Glu, Val), which gives it high surface and biological activity. Considered one of the most potent BSs, surfactin reduces the surface tension of water to about 27 mN/m at concentrations below 5% v/v, in addition to having antibacterial, antifungal, and antiviral activities, with applications in the food, cosmetic, and pharmaceutical industries [167,168,169]. Other representatives include phospholipids synthesised by bacteria and yeasts during growth in hydrophobic carbon sources, such as n-alkanes, the classic examples of which are Acinetobacter spp. and Thiobacillus trioxidanes [159], and polymeric BSs, such as emulsan and liposan, which are produced by yeasts of the genus Candida and applied mainly as emulsifiers in the food and cosmetic industries [170,171,172]. Despite this technological potential, use as agricultural bioinputs lacks more in-depth and systematic studies.

Surfactin is particularly relevant in the agricultural context and is released by rhizobacteria of the genus Bacillus directly into the rhizosphere in biofilms associated with roots, which eliminates the need for a purification step and maintains continuous interaction among the microorganism, BS, and plant [173]. Its mechanism of action is not due to direct attack on phytopathogens but as a molecular signal that induces physiological resistance responses in the plant, activating pathways associated with the production of phytoalexins, thickening of the cell wall, and stress-related enzymes, resulting in greater systemic resistance to different biotic agents and greater vigour in terms of growth [173,174,175]. Other Bacillus lipopeptides, such as iturin and phenengine, play a complementary role. Iturin has strong antifungal action by direct interaction with the membrane of pathogens, while phengicine acts as an antifungal and antibacterial agent. In synergy, surfactin serves as an inducer of resistance, while iturine and fengycin reduce the microbial load of the rhizosphere, making these lipopeptide-producing rhizobacteria promising candidates for sustainable bioinputs in integrated pest and disease management programmes [176].

Several studies have reported the potential of BSs as agricultural bioinputs, serving different functions as biostimulants, pesticides, bioherbicides, and bionematicides. These molecules have considerable structural and functional diversity and are produced by different microorganisms, which expands their application possibilities in sustainable agricultural systems.

Table 3. Classes of biosurfactants, producing microorganisms, and application as agricultural bioinputs reported in the literature.

Class of Biosurfactant	Sub-Class of Biosurfactant	Microorganism	Bioinput Categories	Ref.
Glycolipids	Rhamnolipids	Pseudomonas aeruginosa LBI 2A1	Biostimulant	[156]
		Candida bombicola ATCC 22214	Agricultural defensive	[162]
		Pseudomonas sp. PS-17	Biostimulant	[154]
		Pseudomonas aeruginosa PBS29	Agricultural defensive; biostimulant	[157]
		Pseudomonas or Burkholderia (unspecified)	Biostimulant	[146]
		Pseudomonas putida KT2440 SK4 (variation of Pseudomonas aruginosas)	Bioherbicide; bionematocide	[155]
		Pseudomonas putida KT2440 pWJ02 (variation of Pseudomonas aruginosas)	Bionematocide; Biostimulant	[155]
		Candida bombicola ATCC 22214	Agricultural defensive	[162]
	Sophorolipids	Starmerela bombicola	Agricultural defensive	[147]
		Candida (unspecified)	Biostimulant	[146]
	Trehalolipids	Rhodococcus erythropolis Au-1	Biostimulant	[154]
	Mannosylerythritol lipids	Pseudozyma antarctica T-34	Agricultural defensive	[166]
Lipopeptides	Surfactin	Bacillus amyloliquefaciens S499	Biostimulant	[175]
		Bacillus amyloliquefaciens FZB42-AK3	Biostimulant	[173]
		Bacillus subtilis	Biostimulant	[174]
	Sufactin/fengycin	Bacillus subtilis GLB191	Biostimulant/Agricultural defensive	[176]

summarises the main examples reported in the literature organised by biosurfactant class, producing microorganism, and application as a bioinput.

Different classes of BS have multiple and complementary applications in agriculture depending on the producing microorganism and the structural nature of the molecule. This versatility demonstrates the potential of BSs as key tools in promoting agricultural sustainability, whether in the stimulation of plant growth, protection from pests and pathogens, or the management of weeds. However, the literature points to the need for more in-depth studies, especially under field conditions, to validate the effectiveness of these compounds and enable their application on a commercial scale.

Thus, the efficacy of BSs in these diverse agricultural scenarios is fundamentally rooted in their ability to modify interfacial properties at the microscopic level. Their amphiphilic nature enables them to overcome physical barriers on plant surfaces and enhance the stability of formulations [28]. Figure 5 illustrates the key physicochemical mechanisms, including wetting, emulsification, dispersion, and cuticular penetration, that underpin the multifunctional performance of surfactants in agricultural systems.

5.2. Patents of Biosurfactants with Agricultural Applications

With the aim of mapping the technological advancement and agricultural applicability of biosurfactants, a search was carried out for patents filed between 2010 and 2025.

Table 4. Patent list containing biosurfactants for agricultural application.

Patent Number	Title of Invention	Applications	Action of Biosurfactant	Ref.
EP2894986A1	Compositions and methods for controlling plant-parasite nematode	Materials and methods for nematode control in agricultural crops, integrated pest management, and plant protection	Glycolipid biosurfactants (such as rhamnolipids, sophorolipids, trehalose lipids, and mannosyl erythritol lipids) act as nematicidal agents, reducing motility of nematodes	[177]
CN104886163A	Botanical pesticide compound Phytolacca acinosa and Magnolia officinalis microemulsion and preparation method thereof	Botanical pesticide microemulsion	Saponin glycolipid biosurfactants acting as pesticide agent	[178]
BR112019009924B1	Method and Composition for the Control of Nematode Pests in Plants	Materials and methods for nematode control in agricultural plants and crops, using biosurfactants as pesticides	Glycolipid biosurfactants (such as rhamnolipids, sophorolipids, trehalose lipids, and mannosyl erythritol lipids) act as nematicidal agents, reducing motility of nematodes	[179]
US9554573B2	Binary insecticidal or pesticidal mixture	New mixtures, to processes for preparing these mixtures, to compositions comprising these mixtures and to their use as biologically active compounds.	Saponin glycolipid biosurfactants acting in control of harmful microorganisms or pests in crop protection and material protection and as plant growth regulators.	[180]
BR112020006359A2	Treatment of Mosaic Virus and Bacterial Infections of Plants	Treatment for mosaic viruses and bacterial infections in plants with microbial composition based on biosurfactants	Glycolipidic biosurfactants (e.g., sophorolipids, rhamnolipids, trehalose lipids, mannosilerythritol lipids) and lipopeptides inhibit microbial adhesion, biofilms, and promote natural antimicrobial activity	[181]
US20210100252A1	Microbe-based products for enhancing plant root and immune health	Microbial products to improve plant health, root growth, and immune response in sustainable agricultural applications	Glycolipidic biosurfactants and other microbial metabolites stimulate root growth, increase nutrient absorption, and strengthen the immune system of plants	[182]
WO2020142366A1	Microbial hydrolysates for agricultural pest control	Materials and methods for agricultural pest control by applying microbial hydrolysates and microbial growth by-products as biopesticides	Glycolipidic biosurfactants and microbial lipopeptides act as biopesticide agents that control pests by inactivation, repellency, and other biotic effects	[183]
US20220211047A1	Broad Spectrum Biopesticides Comprising Beneficial Microorganisms	Broad-spectrum biopesticides containing beneficial microorganisms for biological pest control in agricultural crops.	Glycolipids (biosurfactants) act as agents that improve the efficacy of biopesticides by facilitating dispersion, adhesion, and antimicrobial activity against pests and pathogens	[184]
CN113727606A	Agricultural and horticultural bactericide, method for controlling plant disease, and product for controlling plant disease	Product and method for disease control in agricultural and horticultural plants with broad bactericidal activity	Biosurfactants as adjuvant ingredients in the formulation that enhance the efficacy of the active agents in the formulation, but do not specify glycolipids directly	[185]
CN108849984B	Wheat drought-tolerance stress-tolerance compound regulator and application thereof	Regulator and bioproduct for resistance to drought and abiotic stresses in wheat; induction by immersion in seeds; leaf spraying	Glycolipids act as adjuvant biosurfactants: they provide greater leaf adhesion, increase nutrient absorption, prolong retention, provide protection against stress, contribute to biocompatibility, stimulate germination and vigour	[186]
US20210292255A1	Yeast-Based Compositions for Enhancing Rhizosphere Properties and Plant Health	Yeast-based compositions to improve rhizosphere properties and plant health, applicable in sustainable agriculture	Yeast glycolipid biosurfactants (e.g., sophorolipids) promote plant growth stimulation, improve soil microbiota, increase nutrient absorption, and pathogen resistance	[187]
JP2022544263A	Microbial-based compositions for restoring soil health and controlling pests	Restoration of soil health; pest control; plant biostimulus; Soil remediation	Biocontrol of soil pests and diseases; stimulates plant growth; Improves fertility, water retention, biodiversity	[188]
CN113951282	Environment-friendly herbicide containing plant components and preparation method and application thereof	Botanical Herbicide	Glycolipid biosurfactants saponin acting as bioherbicide	[189]
CN116138252B	A pesticide or fertilizer adjuvant and its preparation method and application	Adjuvant for pesticides or fertilizers that improves the absorption, adhesion, and transport of active ingredients, reducing drift and evaporation in agricultural applications	Biological glycolipids (rhamnolipids, sophorolipids and trehalose lipids) act as surfactant agents that reduce the surface tension of the solution, form nanostructured microcapsules with the active ingredients, improving the penetration and efficiency of pesticides and fertilizers	[190]
CN115669673A	Application of notoginsenoside Fe and/or notoginsenoside Fd in preparation of plant source bactericide and prevention and treatment of agricultural fungal diseases	Botanical fungicides and the prevention and treatment of agricultural fungal diseases.	Saponin glycolipid biosurfactants acting as fungicidal agent	[191]
JP7431165B2	Microbial-based products for controlling Fusarium infections in plants and agricultural products	Agricultural biocontrol of Fusarium in plants, soil treatment, roots, aerial parts and post-harvest; Environmental regulator	Glycolipids (e.g., sophorolipids, rhamnolipids) make biocontrol more efficient; They act as biosurfactants promoting fungal destruction, transport via the vascular system and expansion of the antifungal spectrum	[192]
CN116615105A	Compositions and methods for promoting plant health	Promotion of plant health, management and prevention of vascular infections in plants (bacteria, fungi), agricultural use, treatment of soil, roots, seeds, and shoots	Glycolipids act as biosurfactants: facilitate water and nutrient absorption, reduce surface tension in roots/vasculature, dissolve pathogenic biofilms, promote immunity and vascular transport	[193]
WO2025042792A1	Compositions and methods for improved irrigation of soil	Microbial compositions for improved soil irrigation, increased water retention, and improved plant health	Microbial glycolipid biosurfactants (including rhamnolipids, sophorolipids, trehalose lipids, and MEL) act as agents that improve soil water dispersal and penetration by promoting soil aggregation and beneficial microbial activity	[194]
CN118020776	Natural triterpenoid saponin nano pesticide preparation and preparation method and application thereof	Nano-pesticide	Saponin glycolipid biosurfactants acting as pesticide	[195]
WO2025038358A1	Renewable agricultural compositions	Agricultural compositions effective against a variety of agricultural pests; prevention or inhibition of the growth of fungal organisms.	Saponin glycolipid biosurfactants acting as antifungal and antibacterial agents	[196]

summarises the main records, highlighting the applications, mechanisms of action, and trends in the use of these biocompounds in agriculture.

Another relevant aspect is the trend towards multifunctionality, by which BSs cease to act exclusively as biocontrol agents and take on complementary roles as adjuvants that enhance nutrient absorption, improve water retention in soil, reduce the leaching of inputs, and even contribute to the detoxification of pollutants, such as heavy metals. This versatility demonstrates the strategic nature of these molecules in the face of the demands of modern agriculture. Moreover, the temporal progression of patent registrations shows growing alignment with the principles of sustainability and bioeconomy, indicating that innovation efforts are increasingly focused on replacing or complementing synthetic pesticides with safer, more environmentally responsible alternatives. Thus, the patents analysed not only reflect consistent technological advances but also confirm a global trend of the consolidation of BSs as central inputs for the future of sustainable agriculture.

The analysis of patents compiled between 2010 and 2025 shows a clear evolution in the use of BSs applied to agriculture. Initially, inventions were mainly aimed at controlling specific weeds and pests. Over the years, however, there has been a significant advance in the range of applications, covering diverse functions, such as bioherbicides, nematicides, fungicides, liquid fertilisers, and promoters of plant growth. This trajectory demonstrates not only the consolidation of the biotechnological potential of BSs but also progressive diversification in terms of the molecules explored. Glycolipids, including rhamnolipids, sophorolipids, mannosylerythritol lipids (MELs), and trehalolipids, stand out, although combined use with other microbial metabolites has been growing, expanding the spectrum of action of formulations.

6. Absorbent Polymers: Vehicles for the Sustainable Release of Agricultural Inputs

The use of polymeric matrices as vehicles for pesticides, herbicides, and fertilisers constitutes an innovative, sustainable strategy for the controlled release of these inputs, promoting greater agronomic efficiency, a reduction in the doses applied, and the mitigation of environmental impacts [197]. Such matrices include absorbent polymers (APs), which are cross-linked polymers capable of absorbing and retaining volumes of water or aqueous solutions many times greater than their own dry weight [198]. These materials have a three-dimensional organic network with a moderate degree of crosslinking, which enables swelling in an aqueous medium without significant release under pressure. This is due to the osmotic pressure and high amount of hydrophilic functional groups, as demonstrated in Figure 6, where water absorption combines physical interactions (adsorption) and chemical interactions (electrostatic forces), resulting in the expansion of the polymer [199]. According to Ghobashy et al. [200], the presence of ionic (e.g., carboxyl, sulfonic acid, and tertiary amine) and non-ionic (e.g., hydroxyl, amide, and ester) hydrophilic groups contributes to increasing salt tolerance, water absorption capacity, and gel resistance. Due to this liquid retention capacity, such polymers are also called hydrogels or hydrophilic gels.

In addition to their intrinsic water retention properties, hydrogels can respond to environmental stimuli, altering their structure and functionality in the occurrence of variations in pH, temperature, light, or concentration of metabolites in the soil [201]. The swelling and de-swelling behaviour of these APs is directly influenced by such stimuli, as illustrated in Figure 7. Wu et al. [202] found that a hydrogel composed of modified attapulgite, N-isopropylacrylamide, and sodium alginate enabled the accelerated release of urea at acidic or alkaline pH and collapse of the network at 30 °C, favouring the availability of the nutrient. This responsive action demonstrates the potential of these materials for the creation of intelligent systems capable of releasing nutrients or agrochemicals selectively and in line with the physiological needs of plants or environmental conditions. An example is presented by Durpekova et al. [203], who developed a biodegradable cellulose hydrogel with acid whey. The material demonstrated high swelling capacity (>1400% at ideal pH and temperature), good soil performance, and the possibility of reuse for up to five cycles, standing out as a promising sustainable soil conditioner. Other studies on the development of hydrogels for soil are shown in

Table 5. Hydrogels and effects on soil.

Absorbent Polymer Base	Composition of Hydrogel	Water Absorption/Retention	Effect in Soil/Fertiliser	Ref.
Cellulose	Sodium carboxymethylcellulose and 2-acrylamide-2-methylpropanesulfonic acid (AMPS)	Absorption of 604 and 119% in distilled water and saline water, respectively	Improves water retention, increases soil tolerance to salinity, and reduces nutrient loss	[204]
Cellulose	Hydroxyethylcellulose-g-(Acrylic acid-co-2-Acrylamide-2-methyl-1-propane sulfonic)/laterite (HEC-gP(AA-co-AMPS)/laterite)	Absorption of 1294 g/g, 177 g/g and 119 g/g in distilled water, tap water, and 0.9% NaCl solution by weight, respectively	Improves water retention and maintains water availability even under saline conditions	[205]
Starch/Cellulose	Starch-acrylamide-cellulose/poly(ethylene glycol)	Expansion rate 80.24 times in water	Maintains water for a long period, improves water retention, and supports agricultural use	[206]
Starch	Starch loaded with urea, with zeolite microparticles	-	Improves plant growth parameters, increases soil microbial population; fertilizer (N/urea)	[207]
Starch	Hydroxyethyl starch (HES) + AMPS; calcium alginate (CA33) as a carrier	Absorption of 1484 g/g in distilled water; 312 g/g in tap water; 121 g/g in 0.9% saline	Slow release of water, improves soil water retention, increases absorption in saline-alkaline soils	[208]
Chitosan	Chitosan-poly(acrylic acid) graft cross-linked with N,N′-methylenebisacrylamide (MBA)	Water retention up to 67.4%	Improves water retention in sandy soils	[209]
Starch/NR (ecologic)	Eco-friendly cassava amide hydrogel (CSt) + modified natural latex (NR)	Swelling of 2413% and water retention of 58% for 30 days	Excellent water retention, biodegradability, and biosecurity; potential as a sustainable agricultural coating	[210]
Starch	Starch nanocomposite hydrogels bonded to acrylic, synthesized in montmorillonite nanoclay medium	Swelling up to 400 times	Multifunctional vehicle for agriculture, combining water retention and controlled release of pesticide (chlorpyrifos)	[211]
Cellulose	Straw cellulose and linear polymer, such as acrylic acid (AA) and polyvinyl alcohol (PVA), with the introduction of ammonium polyphosphate (APP)	Water absorption of 681.3 g/g in distilled water	Water retention and controlled release of nutrients (N and P), promoting higher crop growth and yield in crops such as wheat	[212]
Cellulose	Cellulose containing diene units (CCDEUs) and AA integrated with urea fertilizer	Absorption of 942.3 g/g in distilled water and 68 g/g in 0.9% NaCl solution by weight	High water absorption and prolonged water retention; controlled release of urea, with recyclability and partial biodegradability	[213]
Keratin	Keratin-AA-MBA (KSA) and ethylcellulose; lignin-coated urea core	Absorption of 587.9 g/g in water	Retains water, releases urea in a controlled manner, improves fertilizer efficiency, remediates soils contaminated by heavy metals, and promotes plant growth	[214]
Protein	Collagen-nitrogen and potassium	Water absorption of 2208 g/g	Water retention, controlled release of fertilizer (N and P) for more than 40 days, biodegradation and adsorption of heavy metals.	[215]
Alginate	Sodium copper alginate, modified with silica nanoparticles containing sodium selenate	-	Controlled release of nitrogen and selenium, antifungal protection (inhibiting Fusarium oxysporum) and improvement of yield and nutritional quality of plants	[216]

Note: The symbol “-” denotes the absence of reported or quantified data for water absorption or retention in the cited reference.

.

Even with such advances, it is necessary to improve the formulation of these polymers to increase their efficiency, optimise interactions with different types of soil, and ensure environmentally compatible degradation, balancing agronomic performance and sustainability [217]. Current research has focused on the development of APs and chemical or physical modification strategies capable of diversifying applications, consolidating these materials as promising tools for agricultural systems (Table 4). A relevant example is the study by Chen et al. [214], who developed a multifunctional ecological fertiliser (MEF) with an outer layer of KSA (keratin-polyvinyl acid-N,N′-methylenene-bis-acrylamide) and an inner layer of ethylcellulose involving lignin-coated urea. The system absorbs water from the soil, enabling the gradual dissolution of urea, which is released slowly. The MEF also degrades into amino acids, carbohydrates, and humic molecules, providing additional nutrients and improving soil quality. Other studies have also focused on the controlled release of agroecological inputs, using double layers and renewable-based polymers and have a mechanism similar to that shown in Figure 8 [216].

In the formulation and performance of these systems, it is critical to consider both the type of polymer and the associated components, as structural characteristics determine efficiency and applicability. Thus, it is essential to understand the different types of APs and their specific properties in order to guide more appropriate application choices. The classification of these materials can be established based on several criteria, the most important of which is the origin of the polymer, which is directly related to its biodegradation potential [217]. APs are categorised as natural, synthetic, or hybrid (combination of both), each of which has intrinsic advantages and limitations. Moreover, the selection of monomers used in the synthesis gives the hydrogel particular properties, modulating its mechanical strength, tolerance to salts, and water retention capacity, which directly impact its performance under different environmental conditions [218].

6.1. Synthetic Absorbent Polymers

Synthetic APs are derived from monomers of a petrochemical origin and obtained mainly through copolymerisation processes. The most widely used are polyvinyl alcohol, polyacrylic acid, methacrylic acid, polyvinyl acetate, polyacrylamide, and polyethylene glycol [199,219]. These materials have significant advantages over natural polymers, such as greater durability, high water absorption and retention capacity, as well as greater mechanical strength and, in some cases, hydrophobicity [197]. Synthetic APs are also characterised by highly controllable properties, the possibility of targeted chemical modification, and broad applicability in industrial production processes [220]. In the superabsorbent sector, acrylic polymers are widely used due to the low relative cost of the raw materials and the simplicity of the synthesis process from high molecular weight precursors [199].

In agriculture, polyacrylate and polyacrylamide stand out as the most widely used synthetic polymers for the improvement of soil structure [221]. Ghobashy et al. [200] demonstrated that poly(vinylpyrrolidone)-based hydrogels applied to Pisum sativum plants under conditions of water stress favoured an increase in soil moisture, greater availability of nutrients, and the improvement of the physiological aspects and growth of the plants, demonstrating the efficiency of these materials in mitigating the effects of water deficit. Despite the benefits associated with the use of synthetic APs, concerns persist regarding the environmental impacts and limited biodegradability, as fully synthetic variants that have a low degradation rate in natural environments, resulting in residual accumulation in the soil.

6.2. Natural Absorbent Polymers

Considering the limitations associated with the use of synthetic APs, there is a growing trend in research aimed at the development and application of biodegradable polymers to overcome such restrictions and improve the functional properties. Making a comparison, Abd El-Hafez et al. [222] found that natural polymers improved the physical properties and moisture of soil, whereas synthetic ones had the opposite effect, resulting in lower lettuce growth. Another study reported that naturally derived APs have unique properties of biocompatibility, non-toxicity, and biodegradability [219,223]. However, the extraction and separation of these materials often involve multiple complex steps, which increases the costs compared to some synthetic APs. Moreover, the properties of natural polymers can exhibit considerable variability depending on the origin, environmental conditions, and the period of production [224]. For instance, nanogels produced from pea starch have a lower water absorption capacity, while those derived from potato starch have greater absorption capacity [225].

APs of a natural origin can be obtained from lipids, proteins, and polysaccharides such as cellulose, starch, chitin, and alginate [226]. Compared to synthetic APs, these materials have limitations related to the absorption rate. However, this aspect can be improved by introducing porosity, which an essential step in the formation of a hydrogel and the increase in swelling capacity. Porosity can be achieved by chemical or physical crosslinking. Chemical crosslinking is preferred, as it confers greater mechanical stability to gels, while physical crosslinking tends to generate more fragile, unstable systems [227]. In the specific case of starch, the use of crosslinking agents of a biological origin, such as citric acid, favours the sustainability of the process [228].

The combination of different natural APs is an efficient strategy for optimising the functional properties of hydrogels. Palma et al. [219] found that the combination of carboxymethylcellulose and starch significantly increased water retention in coarse- and medium-textured soils. In addition to water-holding capacity, the development of optimal hydrogel systems requires attention to variables such as cost, durability, rewetting ability, and structural stability after swelling [227]. Among the available biopolymers, cellulose integrates these characteristics and shows strong potential for the formulation of controlled-release systems. Owing to its biodegradability and high absorption capacity, cellulose-derived superabsorbent hydrogels have been applied in several industrial sectors, particularly in agriculture, to improve soil fertility and water retention [229]. This applicability was demonstrated by Das et al. [230], who developed an agricultural hydrogel based on carboxymethylcellulose and hydroxyethylcellulose cross-linked with citric acid and reinforced with cellulose nanocrystals, achieving a swelling ratio of 600% and enhanced water-use efficiency. Among cellulose-based natural absorbent polymers, bacterial cellulose stands out due to its highly porous nanofibrillar structure and exceptional water retention capacity.

Bacterial Cellulose: Promising Prospects

BC is an extracellular polysaccharide produced by acetic bacteria of the genera Rhizobium, Agrobacterium, Komagataeibacter, Sarcina, among others, among which Komagataeibacter is known for its high production of the polymer [231]. BC is characterised by a highly porous, biocompatible three-dimensional nanofibrillar network with high water retention capacity, mechanical strength, as well as chemical and thermal stability [229,231]. Its production occurs by microbial fermentation, in which bacteria use carbon sources to synthesise cellulose molecules that self-organise into thin fibres, forming a structurally stable matrix [229]. BCs can be obtained in static cultures, resulting in membranes, or in stirred cultures, generating spherical shapes or dispersed suspensions [232]. After synthesis, the biopolymer is recovered, purified with alkaline solutions to remove bacterial cells and impurities, and prepared according to the desired application.

The versatility of BCs is directly related to the possibility of its conversion into nanostructures, such as cellulose nanofibrils (BCNF) and cellulose nanocrystals (BCNC), obtained through physical, chemical, or mechanical processes that preserve its intrinsic properties [233]. These nanoforms exhibit a high specific surface area, a high degree of crystallinity, and an abundance of hydroxyl groups, favouring intermolecular interactions, adsorption of active compounds, and the formation of stable percolating networks [234]. Due to these characteristics, BCs and their nanostructured derivatives have been widely explored in the development of superabsorbent hydrogels, controlled release systems of active ingredients, and other functional materials [231]. As highlighted by Omidian et al. [229], the properties of these hydrogels can be modulated according to the final application, with each stage of the production process directed to meet specific performance requirements.

Diaz-Ramirez et al. [33] optimised the production of spherical BC by Komagataeibacter medellinensis under agitated culture conditions, obtaining structures with a significant increase in water and urea retention capacity, reaching up to 375% of dry weight, which indicates its performance as a superabsorbent and controlled-release system for agricultural use. Similarly, Luo et al. [235] synthesised a composite from BC produced in situ in inorganic bentonite gel that exhibited high water absorption and retention capacity, good thermal stability, and viability as a sustainable, low-cost material. A sustainable cryogel made with hydroxyethylcellulose and BC was developed, to which Ag@TiO₂ and tebuconazole nanoparticles were incorporated, resulting in a porous structure, antimicrobial effect, and the controlled release of pesticide, with high potential for agricultural applications [236].

Thus, each step of the production process is directed towards this purpose. Dehydration, for example, can occur after purification of the polymer. However, this process causes the irreversible collapse of the three-dimensional network, compromising rehydration and restricting the potential use of the material [233]. To mitigate such effects, ex situ modifications, such as crosslinking and incorporation into composites, have been employed to preserve structural integrity and functionality. In this context, the use of nanostructured BC as a stabilizer in Pickering emulsions also stands out, in which nanofibrils or nanocrystals adsorb almost irreversibly at the oil–water interface, promoting high colloidal stability [235]. This property is particularly relevant for the development of agricultural bio-inputs, as it enables the efficient, stable, and controlled encapsulation and delivery of hydrophobic compounds, such as essential oils, pesticides of natural origin, and biostimulants [234]. In this way, employing biodegradable solids, such as BC, constitutes a safer and more environmentally sustainable alternative [237,238].

Biodegradability is an essential aspect in research with cellulose-based materials, especially in view of the concern with the accumulation of residues in the soil. Decomposition depends on factors such as nitrogen availability, temperature, moisture, pH, and the presence of lignin, which influence the activity of cellulolytic microorganisms, including Bacillus, Pseudomonas, Aspergillus, Fusarium, Streptomyces, and Nocardia [237]. Degradation efficiency varies according to the type and degree of chemical modification: a higher the degree of substitution results in a lower the rate of biodegradation, as occurs in highly substituted derivatives, such as acetate and cellulose ethers [238]. Thus, although pure cellulose has greater biodegradability and less persistence in the soil, partially modified versions may be more suitable for applications that require stability or controlled release, as long as the degree of substitution is maintained at levels that do not inhibit microbial action.

Although BC is widely recognised for its functional properties, no patent filings were identified within the time limit stipulated in the methods of this review specifically aimed at the use of this biopolymer in agriculture. Most related patent applications focus on sectors such as packaging, medicine, the food industry, and high-performance materials. This absence suggests that the agricultural applications of BC constitute an emerging field, with considerable opportunities for technological prospecting, development, and the protection of future innovations in this segment.

7. Technological Synergy: Biosurfactants + Bacterial Cellulose

The combination of BSs and BC is technically and functionally justified by the complementarity of their mechanisms: biosurfactants increase the solubility, penetration, and bioavailability of hydrophobic active ingredients and promote better wettability and adhesion to leaf surfaces and soil particles. Conversely, the three-dimensional matrix of BC offers high water retention capacity, mechanical strength, and a porous physical support capable of immobilising or encapsulating active ingredients, enabling controlled release. Thus, integrating BSs with BC creates a system in which BSs improve the transport and initial action of the active ingredient (e.g., increased dispersion and reduced surface tension) and BC regulates the release kinetics and protects the compound from immediate losses due to leaching or volatilisation. This synergy maximizes agronomic efficacy and significantly reduces environmental impacts compared to conventional formulations [27,239,240].

As outlined in Section 5, microbial biosurfactants fundamentally alter the physicochemical dynamics at the plant-environment interface. By lowering surface and interfacial tension, BSs overcome the hydrophobic barrier presented by the waxy leaf cuticle, significantly reducing the contact angle of droplets. This mechanism not only minimizes runoff but promotes stomatal infiltration and cuticular penetration, thereby enhancing the bioavailability of dissolved nutrients and hydrophobic pesticides [28,241]. Beyond their role as adjuvants, BSs function as bioactive amphiphiles. Above their Critical Micelle Concentration (CMC), they form supramolecular assemblies (micelles) that encapsulate poorly water-soluble active ingredients, preventing precipitation and ensuring consistent dosage [28,242]. Crucially, specific classes like rhamnolipids and lipopeptides (e.g., surfactin) exhibit a dual biological function: they display direct antimicrobial activity against phytopathogens and act as Microbe-Associated Molecular Patterns (MAMPs), triggering signaling cascades that activate Induced Systemic Resistance (ISR) [22].

Simultaneously, BC represents a paradigm shift toward sustainable biopolymeric scaffolds. Unlike plant-derived cellulose, BC is synthesized as an ultrapure, highly crystalline 3D nanofibrillar network [243]. This unique nanostructure creates a tortuous diffusion path and a massive surface area, imparting high hygroscopicity. According to Channab et al. [244], BC-based hydrogels function as “smart” delivery systems based on reversible swelling/deswelling cycles: during irrigation, the matrix swells, storing water and nutrients; during dry periods, it releases these resources via diffusion-controlled kinetics, synchronizing nutrient availability with the plant’s evapotranspiration demand. Furthermore, the high aspect ratio of BC nanofibers facilitates the physical entrapment of bioactive molecules, protecting labile compounds from UV degradation and leaching [242,244].

Consequently, the BSs + BC integration offers four distinct agronomic benefits: (i) Reduced leaching losses: BC’s physical retention combined with BS-mediated reversible adsorption prevents active ingredients from migrating to deep soil horizons; (ii) Enhanced Formulation Stability: the interaction between surfactant amphiphiles and the polymer lattice improves dispersion and prevents phase separation; (iii) Spatiotemporal Control: the matrix enables localised release close to the rhizosphere or leaf surface; and (iv) Sustainable Growth Stimulation: by reducing effective doses and environmental losses, selective pressure on non-target organisms is minimized while moisture and nutrient availability are optimized [28,239,241].

7.1. Integrative Formulation Models and Their Impact on Crop Yield

Consolidated and emerging engineering techniques allow for the joint incorporation of BSs and BC into functional platforms, each addressing specific agricultural challenges to improve crop yield:

Smart Hydrogels for Drought Resistance: Hybrid matrices (e.g., alginate/BC or chitosan/BC) incorporating biosurfactants are critical for rain-fed agriculture. These hydrogels act as soil conditioners that not only retain water but aided by the surfactant’s wettability, facilitate the re-hydration of hydrophobic soils. This directly improves crop yield by maintaining turgor pressure during drought stress intervals and ensuring continuous nutrient transport to roots [241].

Micro/Nanocapsules for Precision Protection: Technologies such as coacervation and ionic gelation use BC nanofibers to reinforce capsule walls, while BSs stabilize the internal oil phase. This approach is vital for crop protection, as it shields volatile bio-herbicides or labile biopesticides from UV and thermal degradation. By extending the half-life of these actives in the field, these formulations reduce the frequency of application and prevent yield losses caused by persistent pests and weeds [242].

Bio-active Films and Seed Coatings: Membranes composed of BC reinforced with BS can be engineered as “seed mats” or coatings. This application directly influences stand establishment, the most critical factor for final yield. The BC layer maintains a localized moist microenvironment around the seed, while the BS acts as a biostimulant and antimicrobial shield, enhancing germination rates and seedling vigour even under suboptimal soil conditions [243].

These integrative approaches demonstrate technical-scientific feasibility for modern agriculture, shifting from passive chemical application to responsive, biologically based delivery systems that secure productivity in changing climates [241,242].

7.2. Strategic Applications by Crop Typology and Environmental Context

To bridge the gap between laboratory formulation and field efficacy, application strategies must be tailored to specific crop systems and environmental constraints. The versatility of the BS–BC hybrid platform allows for distinct approaches depending on whether the target is extensive field crops or intensive horticultural systems. For field crops (e.g., soybean, maize, cotton), which cover vast areas and require cost-effective solutions, the primary strategy involves functionalized seed coatings and foliar adjuvants. In these systems, applying large volumes of hydrogel to the soil is often economically unfeasible; instead, thin films of BC enriched with biosurfactants can be applied directly to seeds. This ‘micro-environment’ promotes rapid germination and stand establishment by maintaining moisture around the seed coat and protecting against soil-borne pathogens via the antimicrobial action of lipopeptides [22]. Furthermore, BS-based foliar sprays are crucial for these crops to ensure uniform coverage of biological control agents, especially on waxy leaves like those of corn. Conversely, for horticultural and high-value crops (e.g., tomatoes, vineyards, orchards), the focus shifts to root-zone conditioning and post-harvest protection. Here, the application of superabsorbent BC–BS hydrogels in the planting hole is economically justifiable, acting as local reservoirs that reduce irrigation frequency and prevent nutrient leaching in fertigated systems [244], while edible BC coatings containing biosurfactants can replace synthetic waxes to extend fruit shelf-life.

Beyond crop-specific strategies, the synergistic action of BSs and BC is particularly relevant for mitigating abiotic stresses such as drought and salinity. In semi-arid regions or during ‘dry spells’ in tropical agriculture, BC hydrogels serve as ‘smart’ water buffers where the incorporation of biosurfactants is critical; they reduce the surface tension of water trapped in the polymer network, facilitating its release to the roots when soil water potential drops, a mechanism vital for maintaining turgor pressure during critical growth stages [244]. Regarding saline-alkali soils, biosurfactants aid in remediation by facilitating the leaching of excess salts and improving the solubility of essential micronutrients often unavailable in alkaline pH [28,241]. When combined with BC, which protects the rhizosphere microbial community from osmotic shock, the system promotes better root adaptation in saline environments [242].

Finally, the practical implementation of these technologies holds immense potential for specific geopolitical contexts. As a global leader in tropical agriculture, Brazil faces the challenge of maintaining yields in the ‘Cerrado’ and ‘Caatinga’ biomes, which are prone to irregular rainfall. Supported by the recent National Bio-inputs Policy [245,246], the use of BC–BS seed coatings in the Brazilian could be a decisive factor in mitigating the risks of late-season drought. Similarly, in semi-arid regions characterized by subsistence farming, such as parts of Sub-Saharan Africa, low-cost BC produced from agro-industrial waste (e.g., coconut water, fruit peels) combined with microbial surfactants offers a decentralized solution. These ‘do-it-yourself’ bio-conditioners can significantly increase seedling survival rates in reforestation and family farming projects, directly impacting food security.

7.3. Gaps in the Literature and Innovation Opportunities

Although recent studies support the potential of the synergy between BSs + BC, critical gaps remain: (1) lack of long-term data in the field that correlate release profiles with productivity and real ecological impacts; (2) integrated toxicological and ecotoxicological studies investigating sublethal effects on soil microbiota, pollinators, and aquatic organisms when exposed to BS + BC formulations; (3) scale and economic feasibility, as there is a lack of robust techno-economic analyses for BS + BC production at scale (including the use of agro-industrial waste as substrate); (4) standardisation and regulation of bioformulations that consider biological variability and ensure quality/stability; and (5) fine release engineering, i.e., the need for predictive models that combine physicochemical properties (e.g., surfactant-polymer affinity, sorption/desorption) with expected release profiles in different soil/climate types. Each gap constitutes an opportunity for experimental field work, routine toxicological studies, the development of sustainable production processes, and physicochemical modelling to accelerate the transition of these technologies to agricultural applications [20,247,248].

8. Connection with Sustainable Development Goals and ESG Agenda

The United Nations 2030 Agenda, which is structured on 17 Sustainable Development Goals (SDGs), is widely recognised as an “indivisible whole”, in which the environmental, social, and economic dimensions are deeply interconnected and must be addressed in an integrated manner [248]. In this context, the promotion of sustainable agriculture is central to the achievement of SDG 2 (“Zero Hunger”), requiring a set of interlinked practices, policies, and technologies to combat food insecurity, strengthen the resilience of production systems, and protect natural resources [249]. The incorporation of BSs and BC, especially when produced from agro-industrial waste, constitutes a direct link among technological innovation, the circular economy, and global sustainability policies, offering solutions that connect agricultural productivity, the reduction in environmental impacts, and social inclusion [249,250].

8.1. Sustainability and Use of Renewable Resources

The production of BSs and BC from agro-industrial waste, such as molasses, rice husks, sunflower cake, dairy by-products, and wastewater, exemplifies a circular bioeconomy strategy that reduces costs, avoids the improper disposal of organic matter, and reduces pressure on fossil resources. This approach is directly aligned with SDG 12 (Responsible Consumption and Production) and SDG 13 (Action Against Global Climate Change) by incorporating principles of green chemistry, resource efficiency, and the mitigation of emissions associated with waste disposal [251,252].

The efficient management of food production and consumption, including the reduction of losses and waste along the supply chain, is crucial to increasing food availability and reducing environmental impacts, reinforcing the synergies between SDG 12, SDG 2 (Zero Hunger), and SDG 3 (Health and Well-Being). By valuing residues and by-products as inputs for biotechnological processes, waste is avoided, along with the economic, social, and environmental impacts associated with inadequate waste management, promoting more sustainable food chains. Moreover, the application of this circular logic expands opportunities for the integration of regenerative strategies, strengthening resilient agricultural systems, fostering innovation, and contributing to the achievement of global goals aimed at the efficient use of resources, food security, and the reduction in negative externalities [253].

8.2. Decarbonisation and Reduction of Environmental Impacts

Microbial biosurfactants constitute sustainable alternatives to petrochemical surfactants, offering biodegradability, low toxicity, and less potential for bioaccumulation, thus reducing risks associated with diffuse pollution, aquatic toxicity, and impacts on terrestrial ecosystems. This replacement contributes directly to the reduction in indirect greenhouse gas emissions and is in line with SDG 14 (Life below Water) and SDG 15 (Life on Land). The use of agro-industrial waste as raw material for the production of BSs and BC enhances the circular bioeconomy, avoiding emissions from disposal in landfills or incineration and promoting a reduction in the use of fossil resources [20,253,254,255].

This approach is also in line with SDG 13 (Action Against Global Climate Change) by integrating mitigation and adaptation as complementary strategies. Achieving climate goals requires reducing CO₂ emissions, strengthening resilience, and integrating climate policies into national and sectoral plans. The adoption of clean biotechnologies in the agro-industrial sector serves as an effective mitigation mechanism, contributing to international commitments, such as the Paris Agreement, and plans for the transition to low-carbon economies. This interconnection reinforces the need for climate governance and investments in sustainable technologies, ensuring not only the reduction of environmental impacts, but also social and economic co-benefits, which are essential for a fair, resilient agricultural transition in the face of extreme weather events and the volatility of production chains [256].

8.3. Sustainable Agriculture and Food Security

In agriculture, biosurfactants serve as multifunctional agents—biopesticides, antifungals, biostimulants, and natural chelators—promoting plant growth, improving the bioavailability of micronutrients (Fe, Zn, Cu, Mn), increasing water retention in soil, and inducing systemic resistance. Such properties reduce dependence on synthetic fertilisers and pesticides, enabling more resilient, sustainable agricultural systems. At the same time, BC serves as a matrix for water retention and the controlled release of nutrients, reducing losses due to leaching and water consumption in supplementary irrigation. Such solutions are aligned with SDG 2 (Zero Hunger and Sustainable Agriculture) and SDG 3 (Health and Well-Being), especially in scenarios of water scarcity and land degradation [257,258,259,260]. Achieving global food security depends on integrated strategies that combine technological innovation, sustainable agricultural practices, and public policies capable of mitigating the cumulative effects of climate change, the intensive use of chemical fertilisers, and socioeconomic crises on food systems [261].

8.4. Innovation, Green Economy, and Value Generation

BC produced from low-cost renewable substrates has high crystallinity, chemical purity, biocompatibility, and functional modification capacity, enabling applications in high value-added sectors, such as biomedicine, sustainable packaging, sanitation, and electronics. These advances drive new business models based on renewable inputs and strengthen innovative production chains, which is directly related to SDG 9 (Sustainable Industrialisation, Innovation, and Infrastructure) and SDG 11 (Sustainable Cities and Communities) [245,262,263].

Urban agriculture stands out as a strategy for resilient cities by integrating production practices with green infrastructure, thus reducing the ecological footprint and emissions associated with food transportation, in addition to generating social benefits, such as community inclusion, income generation, and expanded access to fresh food. These spaces function as hubs for civic engagement and participatory governance, strengthening local networks and fairer, more sustainable food systems. Environmental co-benefits include the mitigation of heat islands, increased biodiversity, and ecosystem services, promoting convergence between biotechnology, circular bioeconomy, and sustainable urban design, thus consolidating the ESG agenda as a pillar for regenerative, low-carbon economies [264].

8.5. ESG Agenda and Corporative Competitiveness

The incorporation of BSs and BC as green inputs is in line with the three pillars of the ESG Agenda. In the environmental aspect (E), these biotechnologies contribute to the reduction of the carbon footprint, minimise nitrate leaching, and mitigate diffuse soil pollution [265]. In the social axis (S), decentralised production in small and medium-sized bioreactors favours the inclusion of family farmers and cooperatives, promoting the generation of local jobs and adding value to regional waste. In the governance axis (G), traceability and compliance with national and international regulations make it easier to obtain environmental certifications, such as ISO 14001, and regenerative agriculture seals. Alignment with the Sustainable Development Goals (SDGs), especially SDG 2, depends on the integration of clean technologies, inclusive policies, economic incentives, and transparent governance, which are essential elements for a just agricultural transition guided by ESG principles [266,267,268].

In the corporate context, the integration of ESG practices is no longer optional and has become a strategic imperative. This movement is strengthened by international standards, such as the GRI 13 standards developed by the Global Reporting Initiative (GRI). These sectoral standards launched for agriculture, aquaculture, and fisheries provide specific guidelines for reporting sustainability, focusing on double materiality, which considers significant financial and socio-environmental impacts, preventing symbolic approaches and greenwashing practices. Consistent ESG reporting not only increases transparency and legitimacy but also reduces regulatory, reputational, and financial risks, ensuring access to capital and strengthening global competitiveness. Companies aligned with the SDGs and the ESG Agenda will be more resilient during the transition to low-carbon economies and the challenges imposed by increasingly sustainable production chains [269].

8.6. Current Market Dynamics and Regulatory Incentives

The industrial relevance of biological inputs has grown exponentially, driven by the imperative for sustainable agricultural intensification. The global agricultural biologicals market was valued at approximately USD 13.5–15.1 billion in 2024 and is projected to reach USD 25–34 billion by 2030, exhibiting a compound annual growth rate (CAGR) of 11–14% [270,271,272]. This expansion is led by major industrial players such as Bayer, Syngenta, BASF, Corteva Agriscience, and UPL, which have increasingly integrated biological solutions, including biostimulants and biocontrol agents, into their portfolios to complement conventional agrochemicals.

This market shift is strongly underpinned by supportive public policies aimed at reducing the environmental footprint of agriculture. In the European Union, the “Farm to Fork” strategy, central to the European Green Deal, has set ambitious targets to reduce the use of chemical pesticides by 50% and nutrient losses by at least 50% by 2030, thereby fostering the adoption of bio-based alternatives [273,274]. Similarly, Brazil has recently advanced its regulatory framework with the enactment of pertinent legislation (the National Bio-inputs Law), which specifically regulates the production and on-farm use of bio-inputs, providing legal certainty and encouraging innovation in the sector [245,246]. Such policies not only incentivize research and development but also facilitate market entry for next-generation bio-inputs like the biosurfactant-based formulations reviewed herein.

9. Conclusions and Perspectives

Modern agricultural systems remain highly dependent on synthetic fertilisers and pesticides, a model that, despite historical productivity gains, has revealed critical environmental and economic limitations. However, the transition towards resilient practices is no longer just an ecological imperative but a market reality driven by a projected USD 30 billion bio-inputs sector and supportive frameworks such as the EU’s “Farm to Fork” strategy and Brazil’s National Bio-inputs Policy. Within this transforming landscape, this review uniquely positions BSs and BC not merely as substitutes, but as a synergistic technological platform capable of redefining agronomic efficiency.

By moving beyond fragmented analyses, this article demonstrates that the integration of BSs and BC addresses the “delivery gap” in agriculture. We highlighted how the amphiphilic nature of biosurfactants, capable of modulating interfacial tension and triggering plant immunity (ISR), perfectly complements the nanostructured, hydrophilic scaffold of bacterial cellulose. Together, they form “smart” delivery systems (e.g., hybrid hydrogels and Pickering emulsions) that synchronize nutrient release with plant demand, enhance cuticular penetration, and provide physical protection against UV and leaching. This synergy is particularly decisive for managing abiotic stresses, offering solutions for drought mitigation in semi-arid regions and salinity remediation in degraded soils.

From a practical standpoint, the versatility of this hybrid platform allows for tailored strategies ranging from seed coatings for extensive crops (like soybean in the Brazilian Cerrado) to root-zone conditioners for horticultural systems. Furthermore, the feasibility of producing both biomolecules from agro-industrial residues aligns with the principles of the Circular Economy, offering a decentralized, low-cost pathway to empower subsistence farming in developing regions, including Sub-Saharan Africa.

Looking forward, the effective translation of these technologies from laboratory to field requires overcoming challenges in scalability and shelf-life stability. Future research must prioritize the development of stimuli-responsive formulations (pH/temperature-triggered), the validation of efficacy under diverse edaphoclimatic conditions, and the integration of these products into precision agriculture frameworks. In conclusion, biosurfactants and bacterial cellulose represent strategic tools for the transition towards regenerative and climate-resilient systems. Their development, supported by adaptive regulation and cross-sector collaboration, is essential to ensure their effective contribution to global food security and the sustainable intensification of agriculture.