Production of amylases by B. subtilis using submerged fermentation

Eleven bacterial isolates were isolated from the three different-different places soil sample by serial dilution method and agar plate technique. These bacterial isolated colonies were identified on the basis of colony morphology. Screening of the colony for the amylase activity was done on the MAM (minimal agar medium) supplemented with 1% starch. It showed the maximal amylolytic activity and were identified as Bacillus subtilis in accordance to the Bergey's manual. The physical and chemical factors were also optimized. The strain was improved by UV treatment of 1, 2, 3, 4, 5 minutes. Amylase production was carried out by submerged fermentation. The amylase production was studied as function of carbon source, nitrogen source, pH and temperature. It was verified the maximum amylase activity of 0.01344U was obtained on the 4^th day at 37°C and pH. Partial purification of crude amylase enzyme was done by ammonium sulphate precipitation upto 70% followed by dialysis. Pure enzyme relatively stable at wider pH range of 5–11 and the temperature 4–50°C. The activity was enhanced the present of activators like Mg²⁺. Enzyme activity was decreased in presence of inhibitors like SDS and EDTA.