Review of Enzymatic and Pretreatment Methods for Lignocellulosic Biomass Biorefinery: Technical Advances and Economic Viability

This article is an overview of the advancement and economic potential of pretreatment and enzymatic technologies for lignocellulosic biomass (LCB) biorefineries. The favorable, renewable nature of LCB feedstock from energy crops, specifically residues, makes it a valuable resource for the green production of biofuels and biochemicals. Molecular heterogeneity of the LCB necessitates the use of new solutions in order to make its conversion economical. The literature indicates progress in pretreatment technologies, including deep eutectic solvents (DES), steam explosion, and biological treatment. Progress in enzyme engineering, including immobilization and thermostable enzyme engineering, has also improved the hydrolysis process by minimizing enzyme costs and improving efficiency. Despite such technological advancements, the economic feasibility of LCB biorefineries remains a concern, with pretreatment and enzymatic hydrolysis accounting for the largest share of overall costs. To this end, this review comprehensively evaluates new opportunities for cost minimization, e.g., through scale-up pretreatment and on-site enzyme production. It also discusses policy incentives, such as subsidies, carbon credits, and renewable fuel standards, to enhance the competitiveness of biofuels and facilitate industrialization.