Using 16S rDNAas target site for homologous recombination to improve the alkaline protease production of Bacillus alcalophilus

摘要

Bacillus alcalophilus isolated was used for the production of alkaline protease. The enzyme encoded by alkaline protease gene (apr4) gene. To further improve the production of the strain for industrial requirement, a genetic manipulation system for Bacillus alcalophilus was developed. Additional copies of the aprA gene were transferred into the strain Bacillus alcalophilus and integrated into the 16S rDNA sites, yielding a series of recombinant strains. One of these recombinant strains, designated K23, exhibited superior properties for production of alkaline protease, the protease activity of K23 achieved by (6.19 ± 0.34) × 10~4 U/ml, which is approximately 111.3% higher than that of the wild-type ones for 50-h fermentation. In addition, the new strain was genetically stable for more than 100 generations. These superior characteristics make it to be more suitable than the wild-type strain for alkaline protease production.