[Construct of the stable-produced strain for the thermostable alpha-amylase]

The plasmid pE194 as a vector is used to subclone the thermostable alpha-amylase gene of B. licheniformis and construct recombinant plasmid pNW102. The plasmid pNW102 was transduced into B. subilis BF 7658 by bacteriophage PBS1. The B. subtilis BF7658 (pNW102) strain was treated at non-permissive temperature for a long time, and obtained many recombinant strains. This is the homologous recombination results between alpha-amylase genes of pNW102 and BF7658. The homologous recombination occurs at any site in alpha-amylase gene but there are some heat-spots. We have already screened 2 strains from the recombination strains which can stably produce the thermostable alpha-amylase in B. subtilis BF7658. The analysis of enzymology shows that the characters of the thermpstable alpha-amylase produced from the recombinants strains are the same with that of B. licheniformis.