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.