Lignocellulosic Biomass Valorization: Enzymatic Pretreatment, Bio-Upcycling of Agro-Industrial Waste, and Renewable Biofuel Production

Rising fossil-fuel prices and climate change are driving the search for renewable energy alternatives. Vast amounts of lignocellulosic biomass—agricultural residues, forestry waste, and industrial by-products—are generated annually and, lacking proper management, are often burned in open fields, causing severe pollution and greenhouse-gas emissions. Yet this carbon-neutral feedstock is ideal for building a circular bioeconomy. Lignocellulose is composed mainly of cellulose, hemicellulose, and lignin, whose structural complexity makes it highly recalcitrant to microbial and enzymatic breakdown. Overcoming this barrier requires efficient, cost-effective, eco-friendly pretreatment followed by enzymatic hydrolysis of carbohydrate polymers into fermentable sugars. Compared with energy-intensive physical and chemical methods that generate toxic by-products, biological/enzymatic pretreatments are specific, eco-friendly, and economical, and combinatorial approaches perform best. While carbohydrate conversion is well studied, microbial lignin upscaling remains an evolving, high-value opportunity.Improper management and technical bottlenecks limit the industrial scalability of lignocellulosic biorefineries. Physical and chemical pretreatments are energy-intensive and generate toxic by-products that aggravate pollution and inhibit fermentation, while only a small fraction of about 2% of the lignin—a high-value phenolic resource—is converted into value-added products. This Research Topic aims to develop eco-friendly, economical valorization strategies that fully utilize cellulose, hemicellulose, and lignin for a holistic biorefinery. Specific objectives are: (i) economical bioprocesses for producing cellulases, xylanases, ligninases, and related enzymes for efficient saccharification; (ii) selection of suitable, efficient pretreatment strategies to enhance saccharification; (iii) improved yields of renewable biofuels—bioethanol, bioacetoin, biogas, and other biofuels—via single or mixed microbial cultures, including consolidated bioprocessing; (iv) strain improvement and metabolic engineering of microbial hosts for enhanced saccharification and fermentation; and (v) microbial valorization of lignin into aromatic and value-added products.This Research Topic welcomes contributions on, but not limited to:- Economical microbial production of cellulases, xylanases, ligninases, and other saccharifying enzymes- Selection of ideal, efficient pretreatment strategies for enhanced saccharification- Biofuel production and consolidated bioprocessing integrating enzyme production, hydrolysis, and fermentation into a single, cost-effective step (bioethanol, bioacetoin, biogas, and others)- Strain improvement and metabolic engineering of microbial hosts for enhanced saccharification and fermentation- Microbial and (bio)catalytic valorization of lignin into aromatics, platform chemicals, and functional materials- Techno-economic analysis (TEA) and life-cycle assessment (LCA) validating industrial and ecological viability Topic editors: Bijender Singh, Krishna Kant Sharma, Anuj Kumar Chandel Source: https://www.frontiersin.org/research-topics/84935/lignocellulosic-biomass-valorization-enzymatic-pretreatment-bio-upcycling-of-agro-industrial-waste-and-renewable-biofuel-production