Cellulase: An overview

Cellulases basically belong to a broader enzyme class, glycoside hydrolases, that lead to the cleavage of glucosidic bonds, which are assisted by an acid-base catalytic process. The hydrolytic activity is carried out by two catalytic residues: a nucleophilic moiety or a base and an electrophilic moiety or an acid. The hydrolysis is carried out through the inversion or retention of the anomeric configuration, depending upon the spatial arrangement of the residues which possess the specific catalytic activities. For cellulases with “retaining” hydrolytic activity, the anomeric C having the target glucosidic bond retains the similar configuration after a double-displacement hydrolysis with two specific deglycosylation or glycosylation steps. The present chapter focuses on history, classification of cellulases, and production of this enzyme from different bacteria and fungi for various application. This chapter will be useful for understanding about cellulase enzyme for different application.