Search Results (267)

The increasing generation of agro-industrial residues requires the development of sustainable valorization strategies for converting low-value biomasses into high-added-value products within a circular bioeconomy framework. In this study, tomato peels (TP) derived from the tomato-processing industry and green waste (GW) from urban pruning activities were investigated as substrates for solid-state fermentation (SSF) mediated by Trichoderma harzianum, with the aim of evaluating fungal growth, metabolomic remodeling, and the production of antioxidant bioactive compounds. Different substrate formulations containing TP and GW were subjected to SSF for 7 days, and fungal colonization was monitored. The highest fungal colonization was observed in substrates containing high proportions of GW, whereas pure tomato peels showed negligible colonization, indicating a strong substrate-dependent effect on fungal development. UPLC-QToF-MS metabolomic profiling was subsequently performed on the fermented substrate formulations using three independent biological replicates per treatment, whereas the 100% TP formulation, which showed negligible fungal colonization, was excluded from metabolomic analysis. Results revealed marked differences among fermented substrates, and 22 discriminant metabolites significantly enriched in those containing higher proportions of TP were identified. These metabolites mainly included hydroxycinnamic acid derivatives, flavonoids, lignans, phenolic glycosides, and organic acids, such as coumaric acid, hydroxycaffeic acid, cinnamoylglucose, citric acid, and cyanidin glycosides, suggesting fermentation-associated transformation and release of phenolic compounds. Fermented extracts obtained from mixed substrates enriched in TP exhibited the highest antioxidant activity, with DPPH and ABTS radical scavenging capacities reaching up to 63.48 µmol TE/g dw and 119.67 µmol TE/g dry weight, respectively, together with increased total phenolic content. The integration of microbiological, metabolomic, and antioxidant analyses demonstrated that co-fermentation of tomato-processing byproducts with green waste can modulate fermentation outcomes and enhance antioxidant potential. Overall, this study provides new insights into substrate-driven metabolic transformations during Trichoderma-mediated SSF and highlights the potential of mixed agro-industrial residues as sustainable feedstocks for the production of antioxidant-rich extracts with possible nutraceutical and biotechnological applications. Full article

The utilization of agro-industrial waste in the bioeconomy is crucial for reducing the environmental impact. This study investigated the valorization of a common oat processing waste—oat hulls—using enzyme preparations of different origin and enzyme cocktails based on them. Oat hulls were used in native form and after chemical pretreatment. The following three enzyme preparations were used for enzymatic hydrolysis: Agrocell Plus, CelloLux-A, and Ultraflo Max. An enzyme cocktail consisting of the three enzyme preparations was found to provide a conversion degree of 45% for native oat hulls with simultaneous hydrolysis of cellulose and hemicelluloses, with glucose accounting for only 41% of the total reducing sugars. Enzymatic hydrolysis of the chemically pretreated product confirmed the effectiveness of using enzyme cocktails: the yield of reducing sugars increased 1.4–1.8 times compared to the individual enzymes. The use of the enzyme cocktail consisting of the three enzyme preparations provided a 99% conversion of the accessible fraction of the substrate. Visualization by scanning electron microscopy (SEM) of the hydrolysis of native oat hulls revealed the disappearance of substrate surface irregularities, while in the case of the chemically pretreated product, the substrate disintegration was observed. The comparison of the SEM results of the two substrates before and after hydrolysis confirms the effectiveness of the enzyme cocktails. The contribution of glucose to the total concentration of reducing sugars in the hydrolyzates obtained from the chemically pretreated oat hulls was 85–91%, which allows for predicting the successful application of these hydrolyzates as nutrient media for the biosynthesis of value-added products. Full article

Potato peel waste (PPW) represents a low-cost and eco-friendly by-product with potential for use as a fermentation substrate for the production of antibacterial metabolites by Bacillus species. This study evaluated PPW as a fermentation matrix for Bacillus velezensis and demonstrated that 2% PPW supported optimal production of antibacterial compounds. The cell-free supernatant obtained after 96 h of fermentation exhibited the strongest activity against E. coli 18/22, with a MIC of 62.5 µg/mL. The ethyl acetate extract exhibited rapid bactericidal activity, killing E. coli 18/22 within 30 min at 2× MIC and within 120 min at MIC. The antibacterial activity remained stable up to 80 °C, across pH 4–12, and after treatment with pepsin and chymotrypsin. LC/HR-ESI-MS analysis identified oxydifficidin and surfactins C14 and C15 as the main active compounds. Molecular docking revealed that oxydifficidin and surfactin C15 exhibited the strongest binding affinity toward Shiga toxin II, while surfactin C14 displayed a weaker interaction, suggesting the role of acyl chain length in toxin binding. Both oxydifficidin and surfactins interacted with key residues within the catalytic pocket of the AcrB subunit of the AcrAB–TolC multidrug efflux pump, indicating potential inhibition of multidrug resistance mechanisms. To our knowledge, this is the first report describing the use of PPW as a fermentation substrate for Bacillus velezensis B38 to produce oxydifficidin and surfactin C14 and C15 exhibiting antimicrobial activity against multidrug-resistant E. coli. These findings provide a promising strategy for transforming agro-industrial waste into value-added antimicrobial metabolites, contributing to the circular bioeconomy strategies within the One Health framework. Full article

The inefficient management of agro-industrial residues, particularly cocoa pod husk and mucilage, represents a critical environmental and economic challenge in Santander and Norte de Santander, Colombia, where over 55,000 tons of biomass waste are generated annually from a regional production exceeding 23,500 tons of cocoa beans. Furthermore, these residues, which constitute approximately 70% to 75% of the fruit’s total weight, are currently underutilized, generating severe localized pollution through uncontrolled decomposition and causing substantial economic losses by wasting compounds with high valorization potential. This article proposes the design and systematic experimental calibration and internal cross-validation of an empirical model based on artificial intelligence capable of predicting quantities of valuable compounds, including bioethanol, essential oils, paraffins, antioxidants, and pectins, obtained from cocoa residues. The model integrates critical variables such as cocoa variety, extraction methods, and process conditions, incorporating advanced machine learning techniques trained on a 100% empirical database of eighty-four (84) laboratory trials, combined with a post-inference sensitivity analysis via the Monte Carlo method with 10,000 simulations. Preliminary results demonstrate significant varietal differences; for instance, the CCN-51 variety achieves a mean bioethanol yield of 79.30 ± 4.96 mL/kg with a 95% confidence interval of (69.44–88.93) mL/kg, while the Criollo variety reaches 43.55 ± 2.72 mL/kg (38.14–48.84 mL/kg), exhibiting highly synchronized coefficients of variation of 6.255% and 6.246%, respectively. Furthermore, the integration of a cascading extraction sequence combined with neural networks may potentially contribute to maximizing by-product yields, with theoretical mass balance estimations suggesting a possible reduction of up to 40% in final residue generation compared to conventional isolated extraction pathways, as detailed in the proposed framework. This tool could potentially support the circular economy and alignment with Sustainable Development Goals 7, 9, and 12, while offering a possible pathway to contribute to the competitiveness of the Colombian cocoa industry through data-driven decision-making and sustainable technology adoption. Full article

The increasing generation of agro-industrial by-products from fruit processing represents both an environmental challenge and a valuable opportunity for resource recovery. In this study, tomato, apple, and orange by-products were selected as sustainable substrates for valorization through lactic acid bacteria (LAB) fermentation. The objective was to enhance their functional potential while contributing to waste reduction within a circular bio-economy framework. Selected Lactiplantibacillus plantarum strains were applied to each matrix, and microbial growth dynamics were monitored throughout fermentation. In parallel, experimental data were used to build and validate machine learning-assisted models to predict growth kinetics and identify optimal fermentation conditions. To validate the model, the growth of LAB at 32 °C with a bacterial inoculum of approximately 108 CFU/mL was predicted and subsequently compared with experimental results. The developed models demonstrated reliable predictive capability, with low-to-moderate Root Mean Squared Error (RMSE) across different substrates and growth parameters, ranging from 0.143 (vMaxAvg in apple) to 7.155 (LagAvg in orange). Following model validation, selected matrix–strain combinations were applied to develop food products, in which fermented by-products were incorporated as functional ingredients. The resulting formulations exhibited enhanced antioxidant activity and increased total phenolic content, as determined by DPPH (2,2-diphenyl-1-picrylhydrazyl) assay and phenolic analysis, reaching 56.56 mg GAE/100 g (p < 0.05) and 33.76 mg Trolox eq./100 g (p < 0.05), respectively. Full article

The incorporation of supplementary cementitious materials derived from agro-industrial residues has emerged as a promising strategy to reduce the environmental impact associated with Portland cement production while promoting circular economy principles. This study investigates the influence of palm oil fuel ash (POFA) as a partial cement replacement on the mechanical and microstructural properties of concrete. Concrete mixtures containing 0%, 10%, 15%, and 20% POFA by mass of cement were produced using a constant water-to-binder ratio of 0.47. Compressive strength was evaluated at 7, 14, 28, and 56 days, while microstructural characterization was performed using scanning electron microscopy coupled with energy-dispersive spectroscopy (SEM–EDS) to assess hydration products and the interfacial transition zone (ITZ). The incorporation of POFA resulted in lower compressive strength at early curing ages, with reductions of approximately 16–21% compared with the control mixture, reflecting the slower kinetics of pozzolanic reactions. However, prolonged curing promoted significant strength development. At 56 days, concretes containing 10% and 15% POFA exhibited compressive strengths 3.7% and 9.2% higher, respectively, than the control concrete, whereas the 20% replacement level resulted in a 14.6% reduction. SEM observations revealed a denser cementitious matrix, improved aggregate–paste bonding, and a more refined ITZ in mixtures containing 10–15% POFA. EDS analysis showed Ca/Si ratios of 1.22 and 1.08 for the 10% and 15% POFA mixtures, respectively, indicating the formation of silica-rich C–S–H gel associated with effective pozzolanic activity. The results demonstrate that POFA can be successfully utilized as a supplementary cementitious material in concrete. While the 15% replacement level produced the highest 56-day compressive strength, both the 10% and 15% mixtures exhibited favorable microstructural characteristics and effective pozzolanic activity, indicating that both replacement levels are suitable for sustainable concrete production. Full article

Expansive soils, characterized by pronounced volumetric instability under moisture fluctuations, pose a persistent challenge to the safety, serviceability, and long-term stability of civil infrastructure. In response to these challenges, increasing attention has been directed toward the use of sustainable waste-derived additives as environmentally responsible alternatives for improving problematic soils. This study investigates the mechanical behavior of expansive soil stabilized with waste eggshell powder (ESP) and recycled tire powder (RTP), an elastic polymeric waste material rich in rubber and carbon black derived from discarded tires. A comprehensive experimental program was conducted to evaluate the combined effects of ESP/RTP on soil performance. For this purpose, Atterberg’s limits, compaction, unconfined compressive strength (UCS), Swell potential, and California bearing ratio (CBR) tests were performed on untreated soil and soil modified with up to 25% ESP and 9% RTP. The experimental findings revealed that the incorporation of ESP and RTP significantly reduced the Atterberg limits, optimum moisture content (OMC), and swelling potential of the soil, with the optimum blend of 20% ESP and 6% RTP yielding the most pronounced overall improvement. Such changes signify a considerable reduction in soil plasticity and expansive susceptibility, thereby enhancing the volumetric stability of the treated soil. At the same time, maximum dry density (MDD), UCS, and CBR values increased appreciably, demonstrating improved compaction behavior, greater mechanical resistance, and superior load-bearing performance. Moreover, one-way ANOVA confirmed that the enhancements in UCS and CBR achieved at the optimum mix proportions were statistically significant at the 95% confidence level. Overall, the findings demonstrate that ESP and RTP can serve as a sustainable, cost-effective, and environmentally friendly stabilization solution for improving the engineering performance of expansive soils. Full article

Agricultural biomass, comprising animal manure, food processing residues, lignocellulosic agricultural by-products, and other agro-industrial wastes, is generated in large quantities worldwide, particularly in developing countries. Although these residues pose significant environmental disposal challenges, they represent abundant renewable carbon resources that can be valorized into biofuels, contributing to sustainable waste management and circular bioeconomy initiatives. Biohythane, a gaseous fuel consisting of hydrogen and methane, is primarily produced through two-stage anaerobic digestion, in which dark fermentation generates hydrogen-rich intermediates that are subsequently converted into methane during methanogenesis. The separation of these stages enables independent optimization of hydrogen and methane production, resulting in improved substrate conversion efficiency and higher energy recovery than conventional single-stage anaerobic digestion. In addition, the presence of hydrogen enhances combustion characteristics while reducing greenhouse gas and nitrogen oxide emissions. This review critically evaluates recent advances in biohythane production from agricultural biomass through a structured assessment of peer-reviewed literature retrieved from major scientific databases. The selected studies were synthesized to examine biomass feedstocks, pretreatment technologies, microbial communities, metabolic pathways, reactor configurations, and process optimization strategies influencing biohythane production. The review further discusses the advantages and limitations of different agricultural residues, identifies current technological and economic challenges, and highlights emerging research opportunities to improve process efficiency and facilitate the sustainable commercialization of biohythane as a low-carbon renewable energy source. Full article

The growing demand for natural food colorants has increased interest in sustainable alternatives derived from agro-industrial by-products. This study developed and characterized a food-grade natural brown colorant from date seed waste of Phoenix dactylifera L. (Khalas variety) by process optimization, mineral profiling, phenolic characterization and analysis of its storage stability. A food-grade aqueous extraction system was employed, and a Taguchi L9 orthogonal array was used to optimize the processing parameters affecting color development. Roasting temperature was identified as the most influential factor, contributing 85.75% of the variation in color intensity. Signal-to-noise ratio analysis determined the optimum processing conditions as 200 °C roasting temperature, 5 min roasting time, and 15 min extraction time, yielding an OD₄₂₀ value of 0.927. FTIR analysis confirmed the presence of hydroxyl, carbonyl, aromatic, and carbohydrate-associated functional groups related to thermally generated brown pigments. Further studies demonstrated that both temperature and opaqueness of the storage bottle significantly influence colorant stability. Refrigerated storage in amber containers provided superior retention of total phenolic and flavonoid contents, in addition to a superior antioxidant activity compared with room-temperature storage in clear containers. Mineral profiling revealed significantly high levels of potassium, calcium, phosphorus, and magnesium, with the mineral composition remaining largely stable during storage. HPLC analysis identified catechin and gallic acid as the major phenolic compounds, while ellagic acid was detected exclusively in the glycerol–water extract, indicating enhanced recovery of selected phenolics through solvent modification. Overall, the developed date seed colorant combines color-forming, antioxidant and nutritional properties, while providing a sustainable approach for the valorization of date-processing by-products. The findings highlight the potential application of date seed colorant as a clean-label alternative to synthetic brown colorants and support the development of sustainable food ingredients aligned with sustainable development goals. Full article

Valorizing agro-industrial by-products within a circular bioeconomy provides sustainable alternatives to synthetic pesticides. This study evaluated a coffee production waste (CPW) aqueous extract, obtained via subcritical water extraction, as a multifunctional biopesticide. We assessed its chemical profile, antifungal and insecticidal efficacy, ecotoxicology, allelopathy, and biochemical phytotoxicity. HPLC-DAD-MS revealed high levels of caffeine (12.9 mg/g DM), trigonelline (10.8 mg/g DM), and chlorogenic acids (~8.5 mg/g DM). It demonstrated broad in vitro antifungal activity, inhibiting Botrytis cinerea mycelial growth (84.0%) and conidial germination (98.1%). In vivo, CPW reduced apple gray mold severity to 34.9%, though in planta protection on tomato was partial. The extract reduced Halyomorpha halys egg hatching to 33.0% and increased nymphal mortality to 49.0% via symbiotic disruption, without harming its parasitoid Trissolcus japonicus. However, high acute mortality in the pollinator Osmia bicornis highlights the need for risk mitigation. Crucially, CPW showed negligible phytotoxicity on crops but selectively reduced weed germination by up to 25%, supported biochemically by its non-inhibition of plant defense CYP74 enzymes. In conclusion, CPW extract is a promising bioactive candidate for sustainable crop protection, requiring formulation optimization to enhance field safety and performance. Full article

The cement industry accounts for approximately 8–9% of global greenhouse gas emissions, mainly due to clinker production. Replacing Portland cement with supplementary cementitious materials (SCMs) is a promising strategy to reduce these environmental impacts. This study evaluates the mechanical performance and environmental profile of sugarcane ash (SCA) and energy cane ash (ECA) as SCMs in Portland cement mortars. To the best of the authors’ knowledge, this is the first study to integrate the mechanical performance and life cycle environmental assessment of energy cane ash as a supplementary cementitious material in Portland cement mortars. Mortars incorporating 5–20% ash were tested for compressive strength and accelerated carbonation. An attributional life cycle assessment (LCA), following ISO 14040/44 and using the ReCiPe 2016 method, was conducted with a cradle-to-gate approach. At 28 days under wet curing, 10% ECA replacement achieved slightly higher compressive strength than the reference mortar (102%), while 10% SCA replacement also achieved compressive strength similar to the reference mortar, although slightly lower than that of ECA. Both ashes significantly reduced carbonation depth, indicating improved durability. From a life cycle assessment perspective, replacing cement with 10–20% ECA reduced environmental impacts in nine of the ten impact categories evaluated, including climate change (up to 18.6%), fossil depletion, and metal depletion. SCA also improved most categories, although to a lesser extent. The superior performance of ECA is associated with its higher biomass yield and environmental credits from potassium recovery during ash washing. These results demonstrate that agro-industrial ashes, particularly energy cane ash, can enhance mortar performance while reducing environmental burdens, mitigating industrial waste accumulation, and supporting circular economy strategies and climate change mitigation, thereby offering a viable pathway toward more sustainable cement production. Full article

This review critically analyzes bioactive compounds derived from agro-industrial by-products, including polyphenols, natural pigments, dietary fiber, prebiotics, lipids, proteins, and bioactive peptides. The review examines their chemical characteristics, major agro-industrial sources, and recovery strategies, highlighting both conventional technologies and emerging green technologies, such as ultrasound-assisted extraction, supercritical fluids, and natural deep eutectic solvents (NADESs). Across compound classes, common patterns are identified, including the importance of external plant tissues as primary biological reservoirs, as well as a methodological convergence in extraction processes despite the wide chemical diversity of the molecules. Shared challenges related to compound stability, scalability, and process efficiency are also discussed. The results demonstrate that agro-industrial by-products should be understood as complex, integrated matrices rather than isolated sources of individual compounds, thereby supporting the development of unified biorefinery schemes. Unlike previous reviews focused on individual compound classes, this review integrates multiple classes of bioactive compounds, green extraction technologies, analytical characterization strategies, and industrial valorization approaches within a circular biorefinery framework. In conclusion, this review helps bridge the current fragmented understanding of waste valorization and highlights key opportunities for the sustainable development of high-value-added functional ingredients within the framework of the circular economy. Full article

The growing volume of agro-industrial and food-processing residues has intensified interest in their use as low-cost substrates for microbial bioprocessing. Coffee-derived waste streams, including spent coffee grounds (SCGs), wastewater, pulp, husk, and silverskin, represent abundant but still underutilized biomass resources. This narrative review evaluates their potential as liquid or solid substrates or as components of cultivation media for selected microbial systems, including microalgae, bioremediation- and bioprocess-related bacteria, edible fungi such as Pleurotus spp., and yeasts in the genera Pichia, Kluyveromyces, Saccharomyces, and Yarrowia. The review compares the suitability of individual coffee residues based on substrate composition, pretreatment requirements, inhibitory compounds, process limitations, and reported outputs. Coffee-derived residues can reduce substrate costs, support waste valorization, and partially replace conventional nutrients in microbial processes. However, their broader application is limited by compositional variability, conditioning or hydrolysis requirements, difficulties in process standardization, and downstream processing costs. Current evidence most strongly supports fungal cultivation on SCG-containing substrates, bacterial treatment of caffeine-rich wastewaters, yeast fermentation of hydrolyzed residues, and microalgal use of conditioned liquid streams. The review identifies key research gaps and outlines realistic directions for developing coffee-based microbial bioprocesses within a circular bioeconomy framework. Full article

The increasing demand for sustainable materials is driving research into the valorization of agro-industrial waste as lignocellulosic alternatives in engineered wood product manufacturing. This study investigates the use of bitter orange (Citrus aurantium L.) peel as a bio-based filler in particleboards bonded with a bio-based tannin/hexamine adhesive. Panels were fabricated by partially substituting wood chips with orange peel powder at five levels (0, 2.5, 5, 10, and 15 wt%), hot-pressed at 180 °C for 8 min at a constant biomass-to-adhesive ratio of 9:1 (w/w). Firstly, the effect of temperature on orange peels and then the microscopic structure of the composite was observed through optical stereomicroscopy and SEM. Then, mechanical performance, water resistance, and thermal conductivity were also analyzed. Substitution of up to 10 wt% of wood chips with orange peel allowed for the maintenance of internal bond strength, modulus of rupture, and modulus of elasticity, while the 2.5 wt% formulation yielded a statistically significant improvement in axial thermal insulation. Conversely, when the amount of orange waste rises over 10 wt%, significant decreases in internal bond and modulus of rupture were recorded. These findings demonstrate that C. aurantium peels can be used as a viable filler for formaldehyde-free particleboards, offering a promising strategy for orange waste valorization in the wood panel industry. Full article

The growing demand for safe and minimally processed fresh fruits and vegetables has highlighted the need for effective and environmentally friendly decontamination methods. Conventional washing techniques often fail to remove pesticide residues and microbial contaminants efficiently, while chemical disinfectants raise concerns related to toxicity and sustainability. In this context, natural surfactants and fermentation-derived solutions have emerged as promising alternatives. This critical review presents aspects regarding recent advances in the use of plant-based and microbial surfactants, for the decontamination of fresh products, with highlights on their mechanisms of action, ranging from enhanced removal of hydrophobic residues to disruption of microbial bio-films. Also, particular attention is given to the potential of combining surfactants with bioactive compounds obtained through fermentation processes, as well as to the valorization of agro-industrial waste as sustainable raw materials. The impact of these treatments will contribute to the improvement of product quality, safety, and environmental compatibility. Finally, current challenges related to scalability, standardization, and regulatory aspects are outlined, highlighting the need for further research to support the transition from laboratory studies to real-world applications. Full article