The adverse environmental impacts of the fossil fuel and the concerns of energy security necessitate the development of alternative clean energy sources from renewable feedstocks. Lignocellulosic biomass is a 2nd generation feedstock used in the production of biofuels and bio-based products that are conventionally derived from fossil resources. The biochemical conversion, which entails biomass pretreatment, enzymatic hydrolysis and fermentation, is one major platform used to transform lignocelluloses into biofuels. However, lignin presents many challenges to enzymatic hydrolysis leading to the need of high enzyme dose, low hydrolysis yield, low level of recyclability, high cost of enzymatic hydrolysis (because of the high cost of enzymes), and so on. Therefore, enzymatic hydrolysis, which is not cost effective, becomes one of major cost contributors. To mitigate the negative effects of lignin, extensive research has been conducted to explore the fundamental mechanisms of lignin-enzyme interactions to develop technologies to overcome the negative effects of lignin on enzymatic hydrolysis. Non-productive adsorption, which is characterized by hydrophobic, electrostatic and/or hydrogen bonding interactions, is widely known as the primary mechanism governing lignin-enzyme interactions. In addition, lignin-enzyme interaction is also influenced by steric hindrance (i.e., the physical blocking of enzyme access to carbohydrates by lignin). However, the mechanisms underlying the lignin-enzyme interactions remain unclear. This article aims to present a comprehensive review on the lignin-enzyme interactions (i.e. the mechanism, governing driving forces, modeling, and technologies for mitigating the negative effect of lignin). The current challenges inherent in this process and possible avenues of research in cellulosic biorefinery conclude this article.

化石燃料对环境的不利影响以及对能源安全的关注使得必须从可再生原料中开发替代性清洁能源。木质纤维素生物质是第二代原料，用于生产通常来自化石资源的生物燃料和生物基产品。生化转化需要进行生物质预处理，酶促水解和发酵，是用于将木质纤维素转化为生物燃料的主要平台。然而，木质素对酶促水解提出了许多挑战，导致需要高酶剂量，低水解产率，低水平的可回收性，高成本的酶促水解（由于酶的高成本）等。因此，没有成本效益的酶促水解，成为主要的成本贡献者之一。为了减轻木质素的负面影响，已经进行了广泛的研究以探索木质素-酶相互作用的基本机理，以开发出克服木质素对酶促水解的负面影响的技术。以疏水，静电和/或氢键键合相互作用为特征的非生产性吸附被广泛认为是控制木质素-酶相互作用的主要机理。另外，木质素-酶的相互作用也受到空间位阻的影响（即，木质素对酶进入碳水化合物的物理阻断）。然而，木质素-酶相互作用的基础机制仍不清楚。本文旨在对木质素与酶之间的相互作用进行全面综述（即机理，控制驱动力，建模，和减轻木质素负面影响的技术）。本文总结了该过程中固有的当前挑战以及纤维素生物炼制研究的可能途径。