Studies of different nutrient sources on α-amylase fermentation by bacillus amyloliquefaciens

The aim of this work is to investigate the effect of different carbon sources on α-amylase fermentation with Bacillus amyloliquefaciens. Batch fermentations were carried out. The broths were analyzed for cell density, reducing sugar concentration, and enzyme activity. An initial concentration of around 10 g/l of glucose, maltose, xylose, and starch were individually used as the respective substrates for studies. Higher cell density and higher specific growth rate were obtained from glucose. Maximum cell density of 0.86 g/l can be reached from glucose with a specific growth rate of 0.41 h^-1. However, higher enzyme activity and higher specific enzyme activity were obtained from starch with, respective maxima of 1089 U/ml and 1921 (U/ml)/(g/l). Higher specific enzyme formation rate was also performed by starch substrate. Nevertheless, a better stability of enzyme activity was observed for glucose. Fermentation performance from different aspects by these substrates was thus compared. Starch was then determined, by the highest in (1) enzyme level produced, (2) specific enzyme level formed, (3) specific enzyme formation rate, and also by (4) the acceleration of hydrolysis and therefore the utilization of substrate, as the best carbon source among these substrates for this fermentation.