Technological advancements in the pretreatment of lignocellulosic biomass for effective valorization: A review of challenges and prospects

Potential green energy systems can be explored using competent waste lignocellulosic (LC) biomass transformation to energy, a promising and sustainable substitute for energy resources. The intrinsic recalcitrance caused by inhibitory components, primarily lignin, significantly inhibits biofuel production from LC biomass. LC biomass pretreatment facilitates its disintegration via surface area solubility enhancement and reduction of lignin concentration and cellulose crystallinity. Various pretreatment techniques that promote sustainable LC biomass conversion to valuable organic chemicals and biofuels have been employed to rapidly disintegrate the components (lignin, cellulose, and hemicellulose). Herein, we elucidate recent biomass pretreatment strategies and optimum values of their operating parameters that effectively utilize LC biocomponents. Considering economic feasibility and scale-up possibilities, microwave-assisted deep-eutectic solvent pretreatment can be one of the sustainable schemes for delignification (similar to 87 %) and biofuel production. This study offers insights into the selection of a highly effective and appropriate biomass pretreatment method for green and sustainable energy development.