Identification and Characterization of a Processive Endoglucanase from a Marine Bacterium As a Means to Substitute Cellulbiose Hydrolases

Cellulases are categorized into cellobiose hydrolases (CBHs) and endoglucanases (EGs). CBHs cleave beta-1,4-glycosidic linkages from the ends of cellulose chains thus producing large amounts of soluble sugar (such as cellobiose) from cellluose. CBHs are prevalent in fungi but are rare in bacteria. EGs cleave internally-locating beta-1,4-glycosidic linkages in cellulose chains. Interestingly, processive EGs not only possesses the activity of EGs but also those of CBHs since they can cleave beta-1,4-glycosidic linkages at the end sides of cellulose. As processive EGs can replace fungal CBHs, the importance of processive EGs from bacterial origins in increasing. In this study, we have identified a processive EG from a marine bacterium, and characterized the activity of the recombinant EG as a processive EG. The results from our study can be used for the industrial application of processive EGs, possibly to supplement cellulase mixtures for producing fermentable sugar from lignocellulose feedstocks.