Alkaline Amylase from Bacillus sp. SS-8 and Its Properties

Abstract

Selection of alkaliphilic Bacillus from 27 isolates which produced alkaline amylase based onthe maximum capacity of amylase to hydrolyse raw starch was conducted. The effect of detergentson enzyme efficiency was also investigated. Bacillus sp. SS-8 was the best strain among all theisolates. Maximum amylase activity was achieved in a medium containing 1.5 g/100 ml raw cassavastarch as the carbon source with the initial pH of 11, at 37 ÌC. The culture was harvested between 42-60 hours in the stationary phase. As both alkaline amylase and protein productions, increased alongwith the cell growth, amylase production from this stain should be growth-associated enzyme. Nocontamination occurred although the medium was not sterilized. The optimum pH and temperaturefor starch hydrolysis were between pH 7-12 and 50 ÌC and the crude enzyme was stable in the broadpH range of 7-10 and 30-50 ÌC for 1 hour. It could digest raw-starch granules of wheat higher thanthose of rice, corn and cassava. However, canna and sago granules were hardly hydrolyzed by theenzyme.

Keywords : Alkaline Amylase / Alkaliphilic Bacillus sp. / Cassava Starch / Raw Starch /Starch Binding Amylase