A study on partial purification and characterization of extracellular alkaline amylases from Bacillus megaterium by solid state fermentation.

ABSTRACT

A highly alkaline amylase producing Bacillus megaterium was isolated from enriched soil under lab conditions. In order to enrich the soil for alkaline amylase producing Bacteria, soil was supplied with raw potatoes (substrate) and water at pH 10. Soil was left for 1month. After serial dilution five different colonies were obtained and were screened for amylase production. The culture MJS1105 showing maximum hydrolysis zone was subjected to solid state fermentation using wheat bran as substrate. The enzyme was purified using ammonium sulphate precipitation followed by dialysis. Total activity of 7.056 U was obtained at 37ºC after 96 hours of incubation and was found to have a molecular weight of 63KDa (approx.) by SDS – PAGE. The enzyme was relatively stable between pH 5 – pH 13 and at temperature ranging from 32ºC to 50ºC. Moreover, activity was enhanced by using metal ions such as Ca2+, Mg2+ and Na2+. The decline in activity was observed by adding SDS and EDTA.