Effect of glucose and citrate on α‐amylase production in Bacillus licheniformis

Studies on the α‐amylase synthesis were carried out with two strains of Bacillus licheniformis : a mutant strain 44MB82 and its selected variant 44MB82‐G. The cells were cultivated in a nutrient medium containing glucose or citrate as a carbon source. The results obtained indicated that α‐amylase was produced in both strains without inducers in the medium. The variant strain 44MB82‐G, which synthesized α‐amylase in the presence of 6% glucose, showed 58‐fold increased α‐amylase activity compared to strain 44MB82 grown in the presence of 2% glucose. When cells of both strains were cultivated in a medium with 1% citrate, α‐amylase activity of the variant strain was 5 times higher than that of strain 44MB82. The effects of starch and ATP on α‐amylase synthesis are also discussed.