Expression of Coptotermes formosanus endogenous cellulase gene in E. coli

The endogenous cellulase gene of Coptotermes formosanus was cloned and overexpressed in E.coli. Recombinant cellulases (rCfEG) showed high hydrolytic activity on cellulosic substrates. On CMC (carboxymethyl cellulose), rCfEG acted as endoglucanase, randomly hydrolyzing internal â-1,4-glycosidic bonds and resulting in smear polymers with different lengths, though cellobiose, cellotriose, and cellotetraose equivalents were noticeable. Using filter paper as substrate, however, the major hydrolytic products of rCfEG were cellobiose, cellotriose and trace of glucose, indicating a property similar to that of cellobiohydrolase, an exoglucanase. To our knowledge, it is the first time that the intact cellulase gene of C. Formosanus was heterologously expressed with high cellulolytic activity. The results will have impact on further investigation on designing cellulase-inhibitor based pesticides and applying the cellulases for sugar based biofuel production.