High Efficient Expression in Escherichia coli of Chitinase Gene Cloned from Bacillus circulans C-2

Subcloning analysis of a cloned DNA fragment from Bacillus circulans containing the chitinase gene Chi1 showed that the chitinase gene lies on a 1.7kb PstI-StyI fragment. The chitinase gene could be expressed in Escherichia coli strains JM107, DH5alpha, XL1-blue and TG-1 with various efficiencies. The expression level of chitinase gene was highest in JM107, which was almost the same as that in B. circulans C-2. The molecular weight of extracellular chitinase was 66 kD by SDS-PAGE analysis. Cell location determination of the expressed chitinase showed that the enzyme existed not only in cell periplasm and cytoplasm, but also in extracellular broth. When the expression of the enzyme was optimal, the distribution of enzyme activity in extracellular broth, periplasm and cytoplasm was 35.8%, 32.1% and 32.9%, respectively.