Effect of growth temperature on the externalization and localization of α‐amylase in Bacillus stearothermophilus

Abstract

The synthesis and localization of a-amylase were studied in Bacillus stearothermophilus AN002 at 40,45,50 and 55 "C and also during early exponential, late exponential and stationary phases of growth. The extracellular a-amylase synthesis was highest at 50 "C and at stationary growth phase. Accumulation of intracellular a-amylase was observed in cells grown at 40 "C and was distributed in all the cell fractions. At 50 and 55 "C the cell did not have a-amylase in the protoplasm or protoplasmic membrane. The synthesis and externalization of extracellular enzyme are two processes and the externalization is controlled by growth temperature and cell age. Since little is known about the external factors and cell age that regulate the synthesis and localization of the extracellular enzymes, we have examined the production and cellular localization of a-amylase under different growth temperature and at various stages of growth. We have also attempted to correlate the synthesis and externalization of exoenzyme as a function of growth temperature and cell age.