Carbohydrate-Active Enzymes Inhibitors

In the second-generation biochemicals production chain, pretreatment is an essential step for the lignocellulosic sugar platform, aiming to properly depolymerize the complex recalcitrance structure of lignocellulose matrixes. However, the pretreatment process also results in the depolymerization, translocation and condensation of lignin, and releases various soluble lignins as by-products. These lignin fractions after pretreatment are considered as the inhibitors to the carbohydrate-active enzymes (primarily the cellulase). Except for negatively affecting the cellulase accessibility by physically hindering of cellulose, these inhibitors also possessed severe non-productive adsorption of cellulase and deactivating effects on cellulase. To eliminate the negative influences of the phenolic inhibitors on the enzymatic hydrolysis of cellulase, a variety of mitigation strategies, including the proactive measures, the passive measures, and the modification of cellulase are suggested in previous reports. In this chapter, a brief introduction of the lignin inhibition mechanism toward cellulase activity will be content, and a summarization of the current advances in inhibitors’ mitigation strategies will also be included.