Cloning of two genes from Bacillus circulans WL-12 which encode 1,3-β-glucanase activity

Summary: Two genes encoding distinct 1,3β-glucanases have been cloned from Bacillus circulans and expressed in Escherichia coli. A cosmid library of B. circulans WL-12 DNA was constructed in the broad-host-range cosmid pLAFR1 and screened in E. coli for clones which exhibited 1,3-β-glucanase activity. Two 1,3-β-glucanase-positive clones were identified which contained genes encoding two independent 1,3-β-glucanases as shown by biochemical, physical and molecular analyses. The cosmids, designated pMON5401 (27·1 kb insert) and pMON5402 (24·7 kb insert), encoded 68 kDa and 40 kDa 1,3-β-glucanases, respectively. Both 1,3-β-glucanases were purified from their respective E. coli strains, characterized biochemically, and were shown to exhibit lytic activity against purified yeast cell wall preparations.