DNA FRAGMENT CONTAINING BETA-GALACTOSIDASE PRODUCTION GENE AND PLASMID INTERGRATED WITH SAID DNA FRAGMENT

PURPOSE:To produce beta-galactosidase originated from Lactobacillus bulgaricus by integrating a DNA fragment containing beta-galactosidase-production gene of Lactobacillus bulgaricus into a vector DNA. CONSTITUTION:Lactobacillus bulgaricus SBT0034 (FERM P-10081) belonging to genus Lactobacillus is cultured and the cells are collected and lysed with mutanolysine solution and SDS solution to extract and recover the DNA. The DNA is treated with RNase to obtain a chromosome DNA. The chromosome DNA is completely cut with a restriction enzyme and linked to vector DNA cut with the same restriction enzyme using T4 ligase to form a plasmid containing the above chromosome DNA integrated into the vector. beta- Galactosidase produced by E.coli JM105 containing the recombinant plasmid produced by the above process coincides with a beta-galactosidase produced by Lactobacillus bulgaricus SBT0034.