CLONING AND EXPRESSION OF A BETA-1,3-GLUCANASE GENE FROM BACILLUS-CIRCULANS KCTC3004 IN ESCHERICHIA-COLI

A new gene encoding the beta-1,3-glucanase(laminarinase) of Bacillus c irculans KCTC3004 was cloned into Escherichia coli using pUC19 as a ve ctor. The gene localized in the 5.3 kb PstI DNA fragment was expressed independently of its orientation in the cloning vector showing enzyme activity about 33 times greater than that produced by the original B. circulans. The optimum pH and temperature of the cloned enzyme were p H 5.4 and 50 degrees C, respectively. The molecular weight of the enzy me was about 38,000 and the processing of the enzyme molecule within t he E. coli cell was not observed. The enzyme hydrolyzed laminarin to p roduce laminaritriose, laminaribiose, and glucose as main products, bu t it was inactive for lichenan, CMC, or xylan.