Cloning of the genes for penicillinase, penP and penI, of Bacillus licheniformis in some vector plasmids and their expression in Escherichia coli, Bacillus subtilis, and Bacillus licheniformis

Abstract

By using plasmid pMB9, penicillinase genes (penP and penI) from both the wild-type and constitutive strains of B. licheniformis 9945A were cloned in E. coli. When a low-copy-number plasmid was used, both wild-type and constitutive penicillinase genes could be transferred into B. subtilis. When a high-copy-number plasmid was used, only the genes of the wild type could be transferred. These recombinant plasmids in B. subtilis could all be transferred by the protoplast transformation procedure into B. licheniformis. Transformants of E. coli were resistant to ampicillin (20 .mu.g/ml) in spite of the low penicillinase activities (7 U/mg of cells). However, transformants of B. subtilis and B. licheniformis were sensitive to ampicillin (20 .mu.g/ml) even in high penicillinase activities (> 10,000 U/mg of cells). The secretion of penicillinase was rarely observed in E. coli. Penicillinases secreted from transformants of B. subtilis and B. licheniformis were .apprx. 30 and 60% of the total activities, respectively. The plasmids were used for the construction of hetero- and mero-polyploid structures in host cells, and a regulatory mechanism of penicillinase synthesis in B. licheniformis was discussed.