Search Results (1,305)

The urgent need for bio-based functional materials has driven a shift away from fossil-fuel-sourced materials toward renewable lignocellulosic biomass (LCB). This comprehensive review explores the advancements in LCB carbonization between 2020 and 2026, marking a shift from traditional, low-yield combustion processes toward highly selective and sustainable thermochemical conversion pathways. The primary objective of this review is to evaluate the integration of green pretreatment strategies, conversion technologies, and efficient valorization of the aqueous effluents and by-products. The goal of green pretreatment is to overcome the inherent recalcitrance of LCB without the use of harsh chemicals and reaction conditions, specifically highlighting the effectiveness of deep eutectic solvents (DESs) and ionic liquids (ILs). The review also evaluates the emerging conversion technologies, including hydrothermal carbonization (HTC), microwave-assisted pyrolysis (MAP), and the synergistic co-pyrolysis of LCB with synthetic polymeric wastes. Another novel concept in preparing hard carbon and other related materials is the “lignin-first” biorefinery strategy, which facilitates the subsequent production of high-value aromatic monomers, platform chemicals, and biofuels. The engineered carbon materials are increasingly utilized well beyond their traditional use as solid fuels. The products have been proven to be excellent for use in high-performance energy conversion and storage, serving as renewable bio-based electrode materials for supercapacitors and carbon electrodes in next-generation batteries. Full article

One of the leading drivers of biodiversity loss is land use change due to the ever-increasing demand for food, livestock feed, biofiber, and biofuel. The concept of human appropriation of net primary production (HANPP) was developed to measure the impact that humans have on the environment by accounting for biomass removed from the environment in the form of crops, timber, and grazing. The species–energy hypothesis is an established ecological hypothesis postulating that greater species diversity is correlated with higher levels of energy from plant productivity; this can be measured as net primary production minus harvested HANPP or NPP_ecological. Theoretically, a “biodiversity footprint” could be developed by estimating the reduction in species associated with a volume of biomass extraction, reducing NPP_eco. Achieving this would be an advance in sustainability science. We used the USGS Gap Analysis Project (GAP) dataset for bird species diversity and a unique mapping of HANPP_harvest (from crops, grazing, and timber harvests) at the scale of counties in the conterminous US to test whether HANPP reduces bird species richness. Negative binomial regression finds, however, that HANPP_harvest is only a marginally statistically significant stressor of bird species richness. A secondary measure of NPP_ecological/HANPP_harvest is similarly a marginally significant positive predictor. Consistent with recent literature emphasizing the need to account for spatial autocorrelation in ecological research, however, both HANPP_harvest and NPP_ecological/HANPP_harvest are insignificant predictors of bird diversity in the conterminous US at the county scale when spatial autocorrelation, along with county size and coastal adjacency, are accounted for. We conclude that species richness is determined by a complex set of factors that render using data on HANPP to develop a biodiversity footprint speculative and imprecise in the case of bird species richness in the US. Full article

South Africa possesses substantial bioenergy potential derived from agricultural residues, forestry by-products, municipal organic waste, wastewater sludge, and dedicated energy crops, positioning bioenergy as a potentially important contributor to the country’s low-carbon energy transition. Despite more than two decades of supportive policy, modern bioenergy remains a marginal contributor to the country’s energy system. Although previous studies have examined individual bioenergy technologies, feedstocks, environmental impacts, or policy frameworks, a comprehensive assessment of the alignment between policy ambition, technological readiness, implementation outcomes, and emerging sustainable development opportunities in South Africa remains lacking. This review presents a systematic integrative review of bioenergy development in South Africa, evaluating the alignment between policy ambition, technological readiness, and implementation outcomes. Literature published between 2000 and 2025 was systematically reviewed using Scopus, Web of Science, Google Scholar, and institutional publications. A PRISMA-informed screening process identified 427 records, of which 116 studies met the inclusion criteria for detailed synthesis. Evidence was synthesized across three interconnected dimensions: (i) policy and regulatory frameworks, (ii) feedstock availability and technological readiness, and (iii) deployment outcomes, implementation challenges, and future development opportunities. The findings reveal a persistent implementation gap despite abundant biomass resources and commercially established bioenergy conversion technologies Although global biofuel production exceeded 180 billion liters in 2023, South Africa’s installed bioenergy electricity capacity remains approximately 265 MW, representing less than 0.5% of the country’s approximately 60 GW installed electricity generation capacity. By comparison, installed solar and wind capacities exceed 8 GW and 3 GW, respectively. The review identifies fragmented governance, limited investment incentives, regulatory uncertainty, infrastructure constraints, and inadequate integration of bioenergy into national energy planning as the principal barriers to deployment. The review concludes that South Africa’s principal challenge is not biomass availability or technological capability, but translating policy ambition into coordinated implementation capable of scaling sustainable bioenergy deployment. Full article

Bioenergy (including biofuel) production and use are prerequisites for reducing greenhouse emissions and achieving sustainable development. In this work, on the basis of review and analysis of research achievements and elaborated ontologies in the field, an ontology of sustainable bioenergy is proposed. A methodology for its development includes: goals and scope definition, text corpus composition and extraction of the main concepts, controlled vocabulary and thesaurus building, ontology coding, reasoning, verification and querying. The established ontology has links to other related ontologies and is published in GitHub/Borydel/OSBE repository. Further extension of the sustainable bioenergy ontology is planned as well as its embedding in a dedicated repository. Full article

Agricultural waste valorization offers a sustainable route for developing advanced materials for renewable energy applications. In this study, cellulose nanocrystals (CNCs) were extracted from melon agricultural residues through hydrochloric, sulfuric, and phosphoric acid hydrolysis and incorporated into a poly(vinyl alcohol) (PVA) matrix to fabricate proton exchange membranes for potential applications in glucose biofuel cells. The influence of CNC surface chemistry on membrane morphology, crystallinity, thermal stability, mechanical properties, proton conductivity, and glucose permeability was systematically investigated. CNC incorporation improved membrane compactness, crystallinity, and physicochemical stability compared with neat PVA. Among the developed membranes, PVA/CNC-S exhibited the best overall performance, showing the highest proton conductivity (1.032 × 10⁻² mS·cm⁻¹ at 50 °C) and the lowest glucose permeability (3.25 × 10⁻⁹$\pm 0.15$ cm²·s⁻¹). Furthermore, the composite membranes exhibited enhanced thermal and oxidative stability due to strong intermolecular interactions between PVA and functionalized CNCs. The results reveal that CNC surface chemistry plays a crucial role in regulating membrane transport properties and structural organization. In particular, sulfate-functionalized CNCs improved proton transport while minimizing glucose crossover. These findings highlight the potential of agricultural waste-derived PVA/CNC membranes as sustainable, low-cost, and efficient proton exchange membranes for potential applications in glucose biofuel cells and related bioelectrochemical energy systems. Full article

The increasing global demand for sustainable energy solutions has intensified the need for efficient and environmentally friendly biomass-conversion technologies. Among these, thermochemical processes, such as pyrolysis, gasification, and hydrothermal liquefaction, have emerged as promising pathways for transforming lignocellulosic and other organic waste materials into valuable biofuels and biochemicals. This paper presents a comprehensive evaluation of advanced thermochemical conversion and catalytic conversion methods, focusing on their operational mechanisms, catalytic enhancements, and product yields. The efficiency, environmental impact, and economic feasibility of various thermochemical platforms, including recent developments in catalyst design and process-integration strategies, are compared, and innovative approaches to optimize hydrogen generation, improve carbon efficiency, and minimize undesirable byproducts through tailored reaction conditions and bifunctional catalytic systems are explored. Recent advances as well as the current challenges related to feedstock variability, process scalability, and system sustainability are highlighted. By identifying critical research gaps, this study provides strategic insights aimed at guiding future improvements in thermochemical biomass utilization for clean energy production within a circular economy framework. Full article

Wastewater treatment is undergoing a transition from pollutant removal toward resource recovery, creating opportunities to integrate environmental remediation with circular bioeconomy principles. Filamentous algae have attracted increasing attention as multifunctional biological platforms because their attached growth habit facilitates biomass harvesting while supporting nutrient recovery and biomass valorization. This review synthesizes current knowledge on the roles of filamentous algae in wastewater treatment, with emphasis on nutrient and contaminant removal, biomass production, and the generation of bioenergy, biofertilizers, aquafeeds, and cellulose-based biomaterials. It highlights how filamentous algae differ from conventional suspended microalgae through improved biomass retention, simpler harvesting, and compatibility with attached-growth systems such as algal turf scrubbers and biofilm reactors. The review also examines the ecological interactions between filamentous algae and associated microbial communities that underpin nutrient cycling and treatment performance. Beyond wastewater treatment, it critically evaluates the opportunities and challenges associated with downstream biomass valorization, including biofuel production and the recovery of high-value products within integrated biorefinery frameworks. In addition, the review discusses the principal barriers to large-scale implementation, including limited field-scale validation, variability in biomass quality, contaminant safety, downstream processing requirements, regulatory uncertainty, and the need for comprehensive techno-economic and environmental assessments. Finally, it highlights emerging research directions involving systems biology, advanced process monitoring, artificial intelligence-assisted process control, and integrated biorefinery concepts that may support future development. By integrating biological, engineering, and sustainability perspectives, this review provides a comprehensive framework for understanding the potential of filamentous algae to support resilient wastewater treatment systems and accelerate the transition toward circular resource management. Full article

The world’s food industry faces significant obstacles today as it strives to meet the nutritional needs of its rapidly expanding global population while also managing an immense amount of food processing waste (FPW) generated throughout the entire food supply chain. The widespread use of traditional disposal techniques for food waste (landfilling and incineration) regularly faces challenges related to environmental sustainability and economic efficiency. This manuscript reviews the necessary transition from a linear “take-make-dispose” approach to food production to a more circular model that recycles food waste into high-value intermediate chemicals and renewable energy through the development of biorefineries. The manuscript explores the biochemical composition of food waste, with carbohydrates, lipids, proteins, and bioactive materials, making it a suitable feedstock for different multi-stage biorefinery operations. In addition, this review will evaluate a variety of existing conversion technologies for food processing waste, such as biological methods (e.g., anaerobic digestion and fermentation) and thermochemical methods (e.g., pyrolysis, gasification, and hydrothermal liquefaction), to create various platform chemicals, including organic acids, bio-alcohols and volatile fatty acids (VFAs), as well as the production of sustainable biofuels and biopolymers. The review also elucidates the three most determinative constraints on large-scale industrial implementation of food waste valorisation: feedstock variability, techno-economic feasibility, and the need for comprehensive life cycle assessments (LCAs). The alignment of food waste management strategies with the UN SDGs (in particular, SDG 12 ‘Responsible Consumption and Production’ and SDG 13 ‘Climate Action’) reflects the opportunity for food waste to serve as a foundation for a carbon-neutral, sustainable future. This review provides a strategic roadmap for academics, practitioners, and policymakers to tap into the full potential of food waste through a sustainable circular economy model. Full article

The transition to a low-carbon economy requires sustainable alternatives to fossil fuels. Up-recycling municipal solid waste and forestry biomass into solid biofuels presents a promising waste-to-energy strategy. This study aimed to develop a high-calorific, highly durable hybrid solid fuel without synthetic binders, utilizing the natural interlocking of lignocellulosic and plastic matrices under mild slow pyrolysis. Blends of Eucalyptus sawdust and municipal solid waste rejects (40 wt%) were densified with and without a glycerol binder. The optimal binder-free blend underwent slow pyrolysis at 400 °C and 500 °C to evaluate energy upgrading. Results showed that the binder-free formulation achieved mechanical durability of 99.67%, whereas glycerol severely compromised the dimensional stability of the pellets. Mild pyrolysis (400 °C, 30 min) increased the higher heating value to 27.75 MJ/kg—significantly outperforming local coal (18.3 MJ/kg)—while maintaining trace chloride levels, confirming the production of an environmentally safe, premium-grade energy vector. 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

To reduce dependence on fossil fuels and limit their environmental impact, the development of biofuels represents an effective strategy. Green diesel is a biofuel synthesized from vegetable oil that is fully compatible with conventional diesel engines and therefore represents a promising alternative to mineral diesel. In addition, the use of waste-derived catalysts can further improve the sustainability of the process. In this study, fly ash cenospheres (FAC), an abundant industrial waste, were used as a support to synthesize several transition-metal-based catalysts. The catalysts were tested for the catalytic deoxygenation of vegetable oils in a batch reactor at 320 °C and 40 bar H₂ using 10 wt% catalyst and n-hexane as the solvent. Among the tested catalysts, NiMo(5/15)/FAC exhibited the best performance, achieving complete conversion and producing a biofuel containing 91.7% C₁₅–C₁₈ hydrocarbons. The physicochemical properties of the catalyst were investigated using ICP-MS, FT-IR, XRD, and BET-BJH analyses. The effects of the solvent, feedstock, and catalyst reuse were also evaluated. In the recycling tests, the catalyst activity rapidly decreased; however, the regeneration step fully restored its catalytic performance. These results show that FAC can be effectively valorized as a catalyst support for green diesel synthesis. Full article

Sugarcane bagasse (SCB) represents an abundant lignocellulosic residue with significant potential for integrated biorefinery applications. In this study, an alkaline extraction process was optimized for lignin recovery from SCB using a Box–Behnken Design (BBD) to evaluate the effects of extraction temperature (70–110 °C), NaOH concentration (3–9%, w/v), solid-to-liquid ratio (1:10–1:50, g mL⁻¹), and extraction time (30–90 min). Total phenolic content (TPC) and pure lignin content (PLC) were employed as response variables to identify optimal extraction conditions. Under the optimized parameters, a lignin yield of 17.7% and a TPC of 52.7 mg GAE g⁻¹ were achieved. Structural and thermal characterization by Fourier-transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA) confirmed the preservation of characteristic lignin functionalities and adequate thermal stability for downstream applications. To demonstrate its valorization potential, the recovered lignin was successfully incorporated as a partial substitute for petroleum-derived phenol in the formulation of a lignin-based resin, providing a proof of concept for its utilization in sustainable polymeric materials. In parallel, the cellulose-enriched residual solid (RS) obtained after lignin extraction was subjected to fermentation, yielding 10.3 g L⁻¹ ethanol. This integrated strategy enabled the sequential production of lignin-derived materials and bioethanol from a single biomass feedstock, maximizing resource utilization while minimizing waste generation. The findings highlight the feasibility of coupling lignin recovery with biofuel production and support the development of SCB-based biorefineries for the generation of renewable chemicals, bio-based materials, and sustainable energy carriers. Full article

Ukraine’s energy strategy under martial law necessitates decentralized local energy systems to counter electricity shortages and systemic infrastructure failures. The study develops and validates an optimization model for designing the architecture of decentralized “energy islands” based on circular bioenergy models for agricultural waste use. Empirical verification was conducted using data from the Vinnytsia region in Ukraine. The model accounts for a multi-level structure that separates micro/small generation (0.1–2.0 MW) from medium generation (1–20 MW) based on the logistical radius for raw material collection. The model incorporated the Value of Lost Load (VLL), enabling the monetization of avoided socio-economic losses from energy shortages. In addition, the coefficient of energy island sustainability (I_sred) was introduced to quantitatively assess the effectiveness of investments in terms of replacing external resources. The modeling revealed the nonlinear nature of the total cost function, enabling us to determine an optimal energy-autonomy range of 40% to 50% for communities. At this threshold, the total construction and logistics costs are minimized. The potential socio-economic losses from blackouts are effectively mitigated, as confirmed by the calculated sustainability coefficient (I_sred), which ranges from 0.78 to 0.94 across the studied communities. The resource potential assessment confirms that the region’s total potential is approaching 30 million tons of oil equivalent, driven by solid biofuels, agricultural residues, and energy crops (miscanthus, switchgrass). The classification of biomass supply chains shows that exceeding the transportation radius by more than 70 km at the meso level, or deviating from the optimal logistics lever by 20%, reduces the profitability of projects below the critical limit of 15%, which justifies strict localization within raw-material clusters. This enables local communities to eliminate natural gas consumption, reduce energy supply operating costs by 15%, and ensure the autonomous and stable operation of critical infrastructure facilities during prolonged disruptions to the national power grid. Full article

Food waste has emerged as one of the most pressing global sustainability challenges because of its environmental, economic, and social implications. Nearly one-third of the food produced worldwide is lost or wasted each year, contributing to greenhouse gas emissions, depletion of natural resources, and increasing food insecurity. Advances in circular bioeconomy concepts and sustainable processing technologies have transformed food waste from an environmental liability into a valuable feedstock for producing biofuels, bioplastics, bioactive compounds, functional ingredients, prebiotics, and other high-value products. This review critically examines current strategies for converting food waste into value-added products, including green extraction technologies and biochemical, thermochemical, enzymatic, and microbial approaches. Attention is given to major agri-food by-products, such as fruit pomace, vegetable residues, oilseed meals, dairy by-products, and agro-industrial wastes. Emerging developments involving biorefinery concepts, artificial intelligence, digital biorefineries, synthetic biology, and carbon-neutral production systems are also discussed. Furthermore, the review highlights recent applications of waste-derived fibers, antioxidants, and polyphenols in functional foods, especially bakery products. Finally, key challenges related to feedstock heterogeneity, process scalability, regulatory frameworks, economic feasibility, and sustainability assessment are critically analyzed together with future research directions supporting the transition toward resilient circular bioeconomy systems. Full article