Modulation of cellulase stability and activity by betaine- and choline-polyol based deep eutectic solvents.

Ionic liquids as a potential pretreatment strategy for lignocellulosic feedstocks for sustainable bioproducts

Processes and Products Derived from Lignocellulosic Feedstock: A Biorefinery Approach.

Advancements in Green Pretreatment, Thermochemical Conversion, and By-Product Valorization of Lignocellulosic Biomass for Energy Applications

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.

A comprehensive review of methods for valorisation and production of bioproducts from various cassava wastes

Cassava is a key tropical crop; however, its processing generates large volumes of residues, including peels, bagasse, leaves, stems, and wastewater. Although these wastes are rich in starch, fibre, and lignocellulosic components with high biotechnological potential, they remain largely underutilised. In this context, this review examines current strategies for the recovery and valorisation of cassava processing residues, encompassing physical, chemical, biological, and enzymatic pretreatments, as well as emerging technologies aimed at biofuel and bioproduct generation. Hydrothermal pretreatment stands out for offering a balanced performance between efficiency and inhibitor formation, while acid pretreatment maximises hemicellulose solubilisation but generates higher levels of toxic compounds. Alkaline pretreatments promote effective delignification and enhance enzymatic accessibility, albeit producing effluents that require further treatment. Biological and enzymatic approaches present environmental advantages and low inhibitor formation, although their application is limited by slower kinetics. Emerging technologies, such as ultrasound and non-thermal plasma, show promising potential to enhance sugar release and reduce hydrolysate toxicity, despite the limited number of studies specifically focused on cassava residues. Overall, the integration of complementary routes emerges as a robust strategy to maximise the production of bioethanol, biogas, biohydrogen, and organic acids from cassava wastes. Biorefinery models consistently demonstrate significant energy gains and reduced environmental impacts, reinforcing cassava residues as a strategic platform for circular economy applications. Consequently, the integrated valorisation of cassava processing wastes represents a relevant opportunity to enhance technological sustainability and environmental performance across cassava value chains.

From Fossil to Green: A Low-Carbon Electrochemical Pathway for Lignite Depolymerization

The high-value utilization of lignite is pivotal for the clean transformation of the coal industry. However, traditional methods for preparing humic acid struggle to simultaneously achieve high efficiency, environmental friendliness, and economic viability. This study proposes a mild, clean electrochemical depolymerization strategy to efficiently convert Zhaotong lignite slurry into humic acid under alkaline constant-current conditions. Comprehensive multiscale analyses elucidated the structural and chemical evolution of residual coal throughout the electrolysis process. Based on these findings, the reaction mechanism for humic acid generation driven by electrochemical processes was inferred. Results indicate that within 20 min of alkaline constant-current electrolysis, the dry-basis humic acid yield from Zhaotong lignite reached 57.04%. The residual coal’s oxygen content significantly increased from 23.60% to 35.27%. Aliphatic components fragmented into shorter chains, while the relative distribution of oxygen-containing functional groups underwent dynamic changes. The dominance of C–O bonds strengthened and established a central role, whereas the dominance of COO– bonds weakened. The aromaticity of solid residual coal decreased significantly from 48.28% to 24.33%. This efficient conversion stems from the selective cleavage of Cal-O type bridging bonds and aliphatic side chains via electrochemical means. This process promotes the dissolution and oxidation of low-condensation-degree aromatic clusters into water-soluble humic acids, while higher-condensation-degree bicyclic and polycyclic aromatic clusters remain retained in the residual coal. This work systematically reveals the depolymerization mechanism of lignite macromolecules into humic acids via weak bond cleavage under electric field drive, providing theoretical support for the electro-synthesis of high-value coal-based chemicals.

Utilization of lignocellulosic biomass as sustainable feedstock for the bioproduction of n-butanol as an advanced biofuel: current progress and future perspectives

n-Butanol is a promising advanced biofuel and versatile platform chemical. However, its fermentative production by solventogenic clostridial strains remains economically limited by reliance on costly edible feedstocks of corn and sugarcane. Lignocellulosic biomass provides an abundant, non-food alternative, but its effective conversion necessitates pretreatment which inevitably generates weak acids, furan derivatives, and lignin-derived phenolic compounds. These by-products synergistically inhibit clostridial metabolism by disrupting pH balance, depleting NADH/NADPH, and compromising membrane integrity. To address this bottleneck, this review systematically examines the formation and inhibitory effects of these compounds, and then summarizes the recent strategies of metabolic engineering and co-culture for enhancing the tolerance of strains against various pretreatment-derived inhibitors. In addition, the review traces the progress of pretreatment technologies from conventional acid, alkaline, and physicochemical methods to emerging ionic liquids and deep eutectic solvents, and compares their influence on butanol fermentation performance. By linking lignocellulose pretreatment, inhibition mechanisms, metabolic engineering, and bioprocess engineering, this review provides a systems-level framework for designing more efficient lignocellulosic butanol pathways. Future research interests are also provided, including predictive modeling to control inhibitor generation, strain improvement for lignin-derived phenolic tolerance, techno-economic analysis and life-cycle assessment, and integrated lignin valorization, all aimed at advancing economically viable and sustainable biorefinery processes.