Advances in enhancing the enzymatic saccharification process of lignocellulosic biomasses for bioethanol production

With the increasing global energy demand and the depletion of fossil fuel resources, the development of renewable energy is an inevitable choice for green and sustainable development. Lignocellulose is the world's most abundant renewable resource and has great potential for application in bioenergy. Enzymatic digestion of lignocellulose is a crucial step in converting biomass to biofuels, however, the complexity and stability of the lignocellulose structure limit enzyme access and efficiency. Therefore, exploring efficient and economical pretreatment and enzymatic hydrolysis methods is essential to advance industrial applications. This review provides an overview of the main structure of lignocellulose and the mechanisms of enzyme action, focusing on pretreatment methods and enzymatic hydrolysis enhancement techniques, including hybrid enzyme treatments, additives, and enzyme immobilization. In addition, this review summarizes strategies for the low-cost development of enzymes and optimization of the lignocellulosic biomass conversion process, which will contribute to the economics and sustainability of bioethanol production.