Cloning of an endo-1,4-beta-D-glucanase gene from Clostridium josui and its expression in Escherichia coli.

The gene for carboxymethyl cellulose-degrading enzyme (endoglucanase) from Clostridium josui (FERM P-9684) was cloned in Escherichia coli HB101 with pBR322. A 5.6-kilobase-pair HindIII fragment encoding an endoglucanase was hybridized with C. josui chromosomal DNA. The size of the cloned DNA fragment was reduced with PvuII, and the resulting active fragment (2 kilobase pairs, with restriction sites of EcoRI and PstI) was ligated into pUC118 at the SmaI sites (pUCJ1). The endoglucanase production by E. coli JM103(pUCJ1) in Luria-Bertani broth was enhanced up to approximately three times by maintaining the pH at 6.5 and using 80 mM NaCl.