Green chemical and hybrid enzymatic pretreatments for lignocellulosic biorefineries: Mechanism and challenges

The greener chemical and enzymatic pretreatments for lignocellulosic biomasses are portraying a crucial role owing to their recalcitrant nature. Traditional pretreatments lead to partial degradation of lignin and hemicellulose moieties from the pretreated biomass. But it still restricts the enzyme accessibility for the digestibility towards the celluloses and the interaction of lignin-enzymes, nonproductively. Moreover, incursion of certain special chemical treatments and other lignin sulfonation techniques to the enzymatic pretreatment (hybrid enzymatic pretreatment) enhances the lignin structural modification, solubilization of the hemicelluloses and both saccharification and fermentation processes (SAF). This article concentrates on recent developments in various chemical and hybrid enzymatic pretreatments on biomass materials with their mode of activities. Furthermore, the issues on strategies of the existing pretreatments towards their industrial applications are highlighted, which could lead to innovative ideas to overcome the challenges and give guideline for the researchers towards the lignocellulosic biorefineries.

Automated summary

The green chemical and enzymatic pretreatments play a crucial role in dealing with the recalcitrant nature of lignocellulosic biomasses. Traditional pretreatments only partially degrade lignin and hemicellulose in the biomass, limiting enzyme accessibility and lignin-enzyme interaction. Hybrid enzymatic pretreatments, involving special chemical treatments and lignin sulfonation techniques, enhance lignin modification, hemicellulose solubilization, saccharification, and fermentation processes. This article discusses recent developments in various chemical and hybrid enzymatic pretreatments and highlights the challenges and potential solutions for industrial application in lignocellulosic biorefineries.