Molecular Cloning and Expression of Penicillinase Genes from Bacillus licheniformis in the Thermophile Bacillus stearothermophilus

By using plasmid pTB90, penicillinase genes, penP and penl, from both the wild-type and constitutive strains of Bacillus licheniformis 9945A were cloned and expressed in a thermophile Bacillus stearothermophilus. Bacillus stearothermophilus carrying the recombinant plasmid produced a large amount of penicillinase [3300 U (mg cells)−1] at 48 C, whereas the amount of enzyme produced at 55 C and 60 C was reduced to 660 U (mg cells) −1 and 39 U (mg cells) −1, respectively. Active repressor for penicillinase functioned normally. About 10 to 20% of the total penicillinase was secreted into the culture medium by the transformant of B. stearothermophilus.