Effect of the medium composition on formation of amylase by Bacillus sp.

Abstract

Studies on the α-amylase synthesis was carried out with a moderately thermophilic, facultatively anaerobic Bacillus sp, isolated from soil samples. The cells were cultivated in a complex medium containing soluble starch or maltose as carbon source. The levels of the α-amylase activity detected in culture supernatants varied greatly with the type of carbon source used. Maltose, soluble starch and citrate stimulated α-amylase formation. Addition of exogenous glucose repressed formation of α-amylase, demonstrating that a classical glucose effect was operative in this organism. The concentration of yeast extract was found to be important factor in the α-amylase synthesis by the isolate. The activity of the enzyme increased between 2 and 5 g/L yeast extract concentration and then fell very rapidly beyond this point. The best concentration of peptone to α-amylase formation was found to be around 10g/L.