Overproduction and secretion of Bacillus circulans endo-β-1,3-1,4-glucanase gene (bglBC1) in B-subtilis and B-megaterium

A gene coding for endo-beta-1,3-1,4-glucanase (lichenase) containing a recombinant plasmid, pLL200K, was transferred from Bacillus circulans into a new shuttle plasmid, pLLS920, by ligating linearized DNAs of pLL200K and pUB110. B. subtilis RM125 and B. megaterium ATCC14945 transformed with pLLS920 produced the endo-beta-1,3-1,4-glucanase. The enzyme was produced during active growth with maximum activity. The B. subtilis (pLLS920) enzyme was 83 times (8522 mU ml(-1)) more active than that of the gene donor cells (103 mU ml(-1)). The B. megaterium (pLLS920) enzyme was 7 times (735 mU ml(-1)) more active than that of the gene donor cells. While E. coli secreted only about 10% of the produced enzyme, B. subtilis excreted the enzyme completely into the medium and B. megaterium by about 98%. The plasmid pLLS920 was stable in B. megaterium (98%), and in B. subtilis (51%) but not in E. coli (29%).