Search Results (2,680)

Tidal flats are ecologically important coastal ecosystems with significant carbon stocks; however, although taxon-specific carbon assessments have been conducted in other coastal systems, such data remain scarce for Korean tidal flats, where bivalve aquaculture is actively practiced. This study examined the macrobenthic community structure and carbon stock contributions in two tidal flats on the west coast of South Korea (Seosan and Seocheon) through field surveys conducted in May and August 2023. A total of 110 invertebrate species from five phyla were identified. Annelida showed the highest species richness at both sites (47.4–62.3% of total species), whereas Mollusca dominated biomass and carbon stocks. Two-way PERMANOVA confirmed significant differences in community structure between sites (Pseudo-F = 15.376, p < 0.001) and months (Pseudo-F = 9.489, p = 0.001), and a significant site × month interaction (Pseudo-F = 4.800, p = 0.028). Nonparametric ANCOVA revealed that Mollusca exhibited a significantly higher carbon mass conversion rate relative to wet weight than all the other taxa (p < 0.001). Rank abundance curves and principal coordinate analyses indicated that Ruditapes philippinarum accounted for 86.9% of total carbon mass in Seosan, whereas R. philippinarum and Mactra veneriformis together accounted for 73.5% in Seocheon, despite Annelida comprising the majority of species richness. These results indicate that the macrobenthic carbon stocks of Korean tidal flats are disproportionately concentrated in a few dominant calcifying Bivalvia species rather than across the overall community diversity, with implications for coastal ecosystem management. Full article

Corn processing waste represents an abundant, renewable, and low-cost lignocellulosic resource with considerable potential for environmental remediation applications. Large quantities of residues generated during corn processing, including cobs, husks, bran, and other by-products, are produced annually and can be utilized directly as native biomass or converted through thermochemical processes into hydrochars and biochars. This systematic review provides a comparative analysis of native corn processing biomass, hydrochars produced via hydrothermal carbonization, and biochars obtained through pyrolysis, with a focus on their potential as adsorbents for the removal of organic and inorganic pollutants from soil and water systems. Particular attention is given to the influence of thermochemical conversion processes on the physicochemical properties of the materials, including surface chemistry, porosity, functional groups, and structural characteristics, which govern adsorption mechanisms such as ion exchange, electrostatic interactions, surface complexation, hydrogen bonding, and π–π interactions. Furthermore, the advantages and limitations of each material type are discussed, together with key environmental and techno-economic considerations related to their production and practical application, including indicative production costs (USD per kg of adsorbent) and cost–performance relationships in terms of adsorption capacity. By linking biomass conversion processes, material properties, and adsorption performance, this review aims to provide a comprehensive overview of corn processing waste valorization and to support the development of sustainable adsorbent materials for soil and water remediation. A total of 36 studies were included in the qualitative synthesis following PRISMA guidelines. Full article

This study proposes a sustainable, integrated biorefinery approach to valorize mussel shell waste into high-value products, including chitin, chitosan, and calcium formate. Formic acid was employed as an effective demineralizing agent, enabling not only efficient mineral removal but also the direct conversion of the demineralization effluent into value-added calcium formate. The sequential extraction processes, demineralization, deproteinization, and decolorization, successfully yielded purified chitin (PCH), which was subsequently deacetylated to produce chitosan (CTS) with a degree of deacetylation of 85% and a molecular weight of 75 kDa. The physicochemical properties of all products were characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). FTIR and XRD analyses confirmed the successful extraction of chitin and chitosan, demonstrating the feasibility of mussel shells as an alternative biopolymer source. In parallel, calcium formate (CCF) was obtained from the demineralization effluent with a yield of 94.19%, and its formation was verified by FTIR and XRD. Elemental analysis by XRF exhibited 98.3% CaO with minimal non-toxic impurities. The TGA/DTG profiles of CCF exhibited a well-defined two-step thermal decomposition, confirming its anhydrous form. Overall, this environmentally benign process enables the simultaneous production of multiple value-added products while significantly improving resource utilization and reducing waste generation. The proposed integrated biorefinery model offers a promising, economically viable pathway for marine biomass valorization, aligned with the Bio-Circular-Green (BCG) economy concept. Full article

The growing demand for sustainable, decentralized energy solutions has heightened interest in biomass-based technologies for rural applications. In Mexico, the expansion of oil palm cultivation in humid tropical regions has generated large quantities of agro-industrial residues that remain largely underutilized. This review analyzes the potential of oil palm residues as feedstock for small-scale thermochemical conversion, with a particular focus on gasifier stove technologies. Key residues, including empty fruit bunches, mesocarp fiber, and palm kernel shells, exhibit favorable physicochemical properties, including adequate calorific values and high volatile matter content, which support their suitability for gasification processes. However, challenges related to moisture content, ash composition, and tar formation may affect system performance and require appropriate pre-treatment and operational control. Gasifier stoves, especially fixed-bed and top-lit updraft (TLUD) configurations, represent a viable solution for decentralized energy generation in rural settings, improving combustion efficiency and reducing emissions compared to traditional biomass use. Despite their potential, current bioenergy policies in Mexico remain primarily focused on large-scale biofuel production, limiting the deployment of small-scale technologies. Overall, oil palm residues constitute a promising feedstock for gasifier stove applications, although their successful implementation depends on feedstock optimization, appropriate stove design, and the development of policy frameworks that support decentralized bioenergy systems. Full article

The valorization of agricultural and food industry residues represents an important component of the circular bioeconomy, enabling the conversion of waste streams into value-added materials while mitigating environmental pollution. Spent coffee grounds (SCGs), a solid by-product generated during the extraction of coffee beans with hot water or steam, constitute an abundant lignocellulosic biomass residue. Due to their physicochemical properties, SCGs can be used as low-cost adsorbent materials for the treatment of metal-contaminated wastewater, offering a sustainable alternative to traditional synthetic resins. This review summarizes recent research on the application of SCGs for the removal of metal ions from aqueous systems. The adsorption performance of raw and modified SCGs, including materials obtained via carbonization and chemical functionalization, is comparatively evaluated. Furthermore, key operational parameters governing the adsorption process and the corresponding metal removal efficiencies are discussed. Full article

Insect bioconversion can transform agri-food side-streams into insect biomass while returning nutrients in the form of frass. This study evaluated Tenebrio molitor reared on wheat bran and on substrates in which bran was partially replaced with agri-food side-streams produced in Kosovo, including brewer’s spent grain, brewer's spent yeast, apple and grape pomace, and surplus vegetables. Growth performance, larval composition, and frass nutrient composition were assessed across seven treatments. Larvae reared on wheat bran combined with brewer’s spent grain and melon as wet feed achieved the highest larval weight. Substrates containing wheat bran, apple pomace, and brewer spent yeast also supported high larval weights, but with a higher feed conversion ratio. In contrast, larvae reared on wheat bran, grape pomace, and brewer's spent yeast showed the lowest larval weights. The use of potatoes as wet feed was associated with a longer development period. Larval proximate composition remained similar across treatments, with crude protein contents of 52–56% DM and only limited variation in fat and ash content. Overall, several tested side-streams supported larval growth comparable to wheat bran while generating nutrient-containing frass. Full article

This review proposes a “phenomenon–mechanism–regulation” framework for understanding nitrogen immobilization during the conversion of green waste into growing media. Nitrogen immobilization acts as a double-edged sword: intense short-term immobilization, typically occurring within the first 1–2 weeks after substrate establishment, can rapidly deplete mineral nitrogen and induce plant nitrogen deficiency, whereas the immobilized nitrogen is subsequently incorporated into microbial biomass and lignin-associated organic pools, forming a slow-release reservoir that enhances nitrogen retention and reduces leaching losses. Owing to its extremely high C/N ratio (often >100) and the coexistence of labile carbon fractions and recalcitrant compounds (e.g., lignin and phenolics), green waste exhibits substantially stronger immobilization potential than conventional media. Empirical evidence indicates that nitrogen immobilization can reach 10–115 mg N·L⁻¹ within a few days in wood-derived substrates, and additional fertilization of up to 100 mg N·L⁻¹ may be required to maintain crop growth. Mechanistically, nitrogen immobilization is governed by the coupling of microbial assimilation—driven by stoichiometric C/N imbalance (typically triggered when C/N > 20–25)—and abiotic chemical fixation, including reactions between NH₄⁺/NO₂⁻ and lignin-derived phenolics forming stable organic nitrogen compounds. The relative dominance of these pathways is jointly regulated by carbon quality, nitrogen form, and pH. Based on these mechanisms, regulatory strategies are summarized at multiple scales, including feedstock pretreatment to reduce labile carbon availability, substrate formulation to optimize C/N balance, and model-assisted intelligent fertigation to synchronize nitrogen supply with crop demand. Overall, this study provides a theoretical basis for improving green waste valorization and promoting sustainable horticultural production. Full article

Producing single-cell protein (SCP) from syngas-derived ethanol and acetate offers a sustainable solution to global protein shortages, yet microbial utilization mechanisms for these mixtures remain underexplored. This study establishes a systematic bioconversion strategy using Cyberlindnera jadinii TU389. To mitigate acetaldehyde accumulation during ethanol metabolism, we engineered the strain TU546 to overexpress acylating acetaldehyde dehydrogenase (ADA6). TU546 achieved a maximum biomass of 46.7 g/L and a protein yield of 21.69 g/L, representing enhancements of 28.16% and 23.02% over the wild-type, respectively. Transcriptomic analysis revealed extensive metabolic reprogramming. In the C2 assimilation pathway, upregulated aldehyde dehydrogenase and acetyl-CoA Synthetase 1 accelerated acetate conversion to acetyl-CoA, while downregulated pyruvate decarboxylase and alcohol dehydrogenase minimized carbon flux loss. The upregulation of tricarboxylic acid cycle enzymes, the glyoxylate shunt, and acyl-coA oxidase improved carbon skeleton retention. Moreover, the upregulation of transaminases and N-acetylglutamate synthase, synergized with intensified cell proliferation signaling, redirected amino acid metabolism toward a synthesis-enhanced and degradation-controlled paradigm. This synergistic regulatory network drives the high-efficiency bioconversion of ethanol and acetate into SCP, establishing a molecular mechanistic foundation for the valorization of syngas-derived C2 substrates in biological macromolecule production. Full article

Biomass pyrolysis has emerged as a flexible platform for converting low-value residues into higher-value energy carriers (bio-oil, biochar and gas) and carbon-rich materials, with realistic potential for negative emissions when biochar is deployed in long-lived sinks. Over the last decade, three developments have driven the field forward: first, a finer mechanistic understanding of devolatilization and secondary reactions; second, major improvements in analytical techniques for characterising feedstocks and products; and third, more rigorous techno-economic and life-cycle assessments that place pyrolysis in a broader energy-system context. Recent experimental work on forestry and agro-industrial residues has clarified how biomass composition, ash chemistry and operating conditions jointly govern product yields, energy content and stability. Parallel advances in GC×GC–MS, high-resolution mass spectrometry, NMR and thermogravimetric methods have shifted the discussion from bulk “bio-oil” and “char” to families of molecules and well-defined structural domains, which can be deliberately targeted by reactor and catalyst design. Data-driven models, ranging from support vector machines applied to TGA curves to ANFIS and random forests for yield prediction, are now accurate enough to support process screening and multi-objective optimisation. At the system level, commercial fast pyrolysis biorefineries report overall useful energy efficiencies on the order of 80–86%, while slow pyrolysis configurations centred on biochar can be economically viable when carbon storage and co-products are appropriately valued. Thermodynamic analyses confirm that indirect gasification via fast-pyrolysis oil sacrifices some energy and exergy efficiency relative to direct solid-biomass gasification but may offer logistical and integration advantages. This review synthesises recent work on (i) feedstock and process characterisation; (ii) state-of-the-art analytical methods for bio-oil, biochar and gas; (iii) modelling and machine-learning tools; and (iv) energy-system deployment of pyrolysis products. Throughout, the emphasis is on how characterisation and modelling inform concrete design choices and on the trade-offs that arise when pyrolysis is considered as part of a wider decarbonisation portfolio. By integrating laboratory-scale characterisation with system-level modelling, this review aligns biomass pyrolysis with several United Nations Sustainable Development Goals (SDGs). The optimisation of thermochemical conversion pathways for forestry and agro-industrial residues directly supports SDG 7 (Affordable and Clean Energy) by enhancing the efficiency of bio-oil and syngas production. Furthermore, the deployment of biochar as a stable carbon sink for negative emissions and soil amendment addresses SDG 13 (Climate Action) and SDG 15 (Life on Land). By converting low-value waste streams into high-value energy carriers and chemicals within a circular bioeconomy framework, the research further contributes to SDG 12 (Responsible Consumption and Production) and SDG 9 (Industry, Innovation and Infrastructure). Full article

Plastic manufacturing depends heavily on petroleum-derived monomers like terephthalic acid, the main component of polyethylene terephthalate (PET). However, the depletion of fossil resources and increasing environmental concerns have heightened the need for sustainable alternatives. Lignocellulosic biomass has emerged as a promising resource due to its renewable, abundant, and eco-friendly nature. Understanding its chemical composition enables conversion of this biomass into platform chemicals, such as 2,5-furandicarboxylic acid (FDCA) and lactic acid, derived from cellulose and hemicellulose. These can be polymerized into bio-based plastics such as polyethylene furanoate (PEF), polylactic acid (PLA), and polyhydroxyalkanoates (PHAs), offering greener alternatives to fossil-based plastics. PEF features rigid furan rings that enhance thermal stability, mechanical strength, and barrier properties, and reduce gas permeability compared to PET. PLA is a renewable, biodegradable plastic widely used in packaging and medical applications. This review covers the chemical composition of lignocellulosic biomass cellulose, hemicellulose, and lignin, and various pretreatment strategies, chemical, physicochemical, and physical, to overcome biomass recalcitrance and improve conversion efficiency. It also highlights recent catalytic advances in transforming cellulosic carbohydrates into bio-based plastic precursors such as FDCA and lactic acid. Lastly, this review discusses polymerization pathways for producing PEF and PLA, emphasizing their role in reducing the environmental impact of polymer manufacturing and promoting green chemistry principles. Full article

Lignocellulose represents an abundant repository of renewable carbon. Derived from various plant sources, it holds tremendous potential as a renewable and sustainable feedstock for the production of valuable chemicals and fuels. However, its solid fermentable compounds, cellulose and hemicellulose, are embedded within complex lignin structures and are therefore poorly accessible to microbial conversion. This paper describes an artificial rumen reactor (ARR) that uses anaerobic microbes from the cattle rumen to increase the release of fermentable carbon from recalcitrant biomass. We outline the development of an ARR for the efficient conversion of lignocellulosic grass into volatile fatty acids (VFAs), which are valuable precursors for the production of a range of bioproducts, including biofuels, biomaterials, and biochemicals. The ARR, a 4-L bioreactor equipped with a ceramic filtration unit, has been optimised and was operated for extended periods of continuous VFA production. Across distinct short- and long-term observation periods, and independent of the cow from which the rumen microbes originated, the bioreactor demonstrated the ability to sustain VFA production, indicating robustness and stability. At an input of 60–80 g dry grass d⁻¹, the system produced approximately 6 mol VFA per kg of dry matter input (DMI). The decoupling of the Solid Retention Time (SRT; 10 days) and the Liquid Retention Time (LRT; 0.5 days) prevented inhibition of the VFA production. The VFA profile was dominated by acetic and propionic acids, comprising 68% and 19%, respectively, with butyric acid and minor VFAs accounting for the remainder. The application of low oxygen levels (<10%) in the reactor via limited aeration did not affect the VFA yield or its profile. Full article

The growing demand for sustainable energy sources has intensified research on the valorization of biomass residues as feedstocks for energy production. This scoping review provides a comprehensive analysis of recent technological approaches for converting coconut and açaí residues into energy carriers and bioenergy products. A systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. In addition to synthesizing the existing literature, this study evaluates the technology readiness level (TRL) of the reported conversion pathways based on the experimental evidence provided in the reviewed studies. The literature search was conducted using Scopus, Web of Science, and ScienceDirect, focusing on peer-reviewed publications between 2015 and 2025 that reported experimental or pilot-scale research on thermochemical, chemical, and physical conversion processes for coconut and açaí residues. The TRL assessment indicates that most technologies remain at laboratory validation stages, with only a limited number reaching pilot or prototype demonstration levels. Nevertheless, several pathways—particularly thermochemical and densification processes—show promising potential for decentralized bioenergy applications. These findings are especially relevant for regions where coconut and açaí value chains generate significant volumes of agricultural residues. Their valorization could support decentralized energy systems, improve residue management, and contribute to sustainable bioeconomy strategies. Overall, this review identifies the main technological advances, limitations, and research gaps associated with the energy conversion of coconut and açaí residues, providing insights for future technological development and deployment. Full article

Agri-food processing in Europe generates large quantities of organic residues that remain insufficiently valorized despite their significant biochemical potential. Among these, wastes derived from root vegetables and anthocyanin-rich crops represent a distinct category of non-lignocellulosic biomass characterized by high moisture content, low lignin levels, and substantial concentrations of fermentable carbohydrates and bioactive compounds. This review provides a systematic overview of the origin, composition, and valorization potential of these residues, as well as extraction methods, with particular emphasis on root vegetable processing wastes and pigment-rich agri-food by-products. Valorization options are discussed within an integrated biorefinery perspective, particularly for specific compositional characteristics of the investigated waste streams related to suitable recovery strategies, followed by the conversion of post-extraction residues into secondary products and bioenergy. These options are evaluated in relation to the origin, biochemical profile, and valorization potential of each waste stream, as detailed in the dedicated sections of the review. Cascading utilization strategies are highlighted as a means to improve resource efficiency and reduce environmental burdens compared to single-route treatment options. By integrating information on feedstock characteristics and processing pathways, this review contributes to a better understanding of non-lignocellulosic agri-food wastes and supports the development of sustainable valorization strategies in the European circular bioeconomy. Full article

Municipal wastewater represents an underutilized secondary biomass resource rich in organic carbon and nutrients that can be valorized through biotechnological conversion. In this study, we developed an integrated multi-microbial biorefinery platform to transform municipal wastewater into value-added biofuel via sequential bacterial treatment, microalgal biomass generation, and fungal-assisted harvesting. Wastewater was first pretreated with Bacillus subtilis to enzymatically hydrolyze complex organic substrates and enrich the medium with bioactive metabolites, including auxins and gibberellins. The conditioned wastewater was subsequently used to cultivate Chlorella vulgaris, followed by biomass recovery using Trichoderma viride pellets as a sustainable bioflocculant. The integrated consortium significantly enhanced nutrient removal efficiency and promoted algal biomass accumulation, lipid enrichment, and biodiesel productivity compared to monoculture controls. Elevated hydrolytic enzyme activities (cellulase, protease, and amylases) facilitated organic matter conversion into bioavailable substrates, while increased phytohormone levels stimulated algal growth and lipid biosynthesis. Additionally, fungal bioflocculation substantially improved biomass recovery efficiency, reducing the need for energy-intensive harvesting technologies. This work highlights the potential of a biotechnology-driven approach for integrating wastewater remediation with biofuel production. By integrating microbial metabolism, enzymatic transformation, and sustainable separation processes, the proposed biorefinery system suggests a potentially low-carbon approach for simultaneous environmental remediation and biomass valorization, although further life cycle and energy balance analyses are required to validate this aspect. Full article

Thermochemical/catalytic co-processing of biomass and solid wastes is a promising route for waste valorization, low-carbon energy recovery, and the co-production of fuels, chemicals, and carbon materials. Conventional pathways, including pyrolysis, gasification, liquefaction, and carbonization, provide the basic framework for mixed-feed conversion. Emerging routes, such as flash Joule heating, microwave-assisted conversion, plasma processing, supercritical water treatment, solar-driven systems, and machine-learning-assisted optimization, further expand opportunities for process intensification and selective upgrading. Owing to feedstock complementarity, including hydrogen donation from plastics, catalytic effects of ash minerals, and interactions among reactive intermediates, co-processing can enhance deoxygenation, hydrogen generation, aromatization, and carbon utilization. Major challenges remain, however, including feedstock heterogeneity, reactor scale-up, catalyst stability, and the limited transferability of laboratory-scale synergy to realistic waste streams. Future progress should therefore focus on continuous validation, mechanistic clarification, and integrated techno-economic, life-cycle, and data-driven assessments. Full article