Maltose adaptive mutant of heterotrophic marine bacterium, Alteromonas espejiana Bal-31: Changes in the growth and the induction of extracellular α-amylase

摘要

Growth of the heterotrophic marine bacterium, Alteromonas espejiana Bal-31 was inhibited in the presence of sucrose, maltose and even glucose, but not with starch. Extracellular α-amylase was induced with a lag phase of 2 h in the presence of starch. In contrast, cell growth of the S2a mutant was not affected by the addition of maltose, and starch was ineffective in the induction of extracellular α-amylase in this mutant. Activity of extracellular α-amylase was induced from the S2a mutant with a 4-h lag phase in the presence of maltose, and the high level of enzyme activity was maintained for at least 24 h. Activity of α-amylase induced by both wild type starch and S2a mutant maltose cultures were mainly observed in extracellular locations. This activity could be stopped by tetracycline treatment, indicating that enzyme induction was dependant on gene expression and not on enzyme protein secretory mechanisms. Our results showed that the mutation in S2a changed the growth and the modulation of the specific α-amylase in response to carbon nutrients.