5-101: Biochemical characterization of cellobiohydrolases from different GH families

Cellulose is the major structural component of plant cell walls and the most abundant biological polymer on earth.  Many cellulolytic fungi degrade native crystalline cellulose using a set of cellulolytic enzymes dominated by two cellobiohydrolases (EC 3.2.1.91), CBHI and CBHII.  These two enzymes often work cooperatively (exo-exo synergy), and appear to be the key enzymes for hydrolysis of crystalline cellulose.  Cellobiohydrolases are processive enzymes liberating cellobiose from reducing or non-reducing ends of the polymeric cellulose chains.  Most of the cellobiohydrolases belong to glycoside hydrolase (GH) families 6 and 7.  This paper will compare properties of various cellobiohydrolases from families 6 and 7.  Substrate specificity, thermostability, specific activity on selected substrates, and pH and temperature activity profiles will be discussed in relation to performance of the cellobiohydrolases in hydrolysis of dilute-acid pretreated corn stover at various process conditions.