Stable hyper-production of Escherichia coli beta-lactamase by Bacillus subtilis grown on a 0.5 M succinate-medium using a B. subtilis alpha-amylase secretion vector.

Extracellular production of Escherichia coli beta-lactamase by Bacillus subtilis, using a B. subtilis secretion vector constructed from its own alpha-amylase gene, was promoted when the cells were grown on LG-medium containing 0.5 M succinate under poor aeration conditions. The amount of the enzyme secreted was 50 to 60 times as large as that obtained by cultivation of the cells on LG-medium under good aeration conditions. The effect of protease-deficient mutant of B. subtilis on the enzyme production by B. subtilis was significant while that of protease inhibitors was negligible or inexistent.