Improvement of rifamycin B production using mutant strains of Amycolatopsis mediterranei

Two mutant strains of Amycolatopsis mediterranei VA17 and VA18 were isolate d using physical (UV) and chemical (NTG) mutagens gave high rifamycin B tha n the parent type when grown in the same fermentation medium with a pH of 7 .2, temperature 32 degreesC for a period of 12 days. The cultural condition s of both mutant strains are similar to the parent strain except temperatur e which was higher by 4 degreesC. By this mutation and selection study, rif amycin B production was improved from 1400 mg/l to 2450 mg/l.