A thin layer chromatographic comparison of raw and soluble starch hydrolysis patterns of some α-amylases from Bacillus sp. isolated in Serbia

Abstract

Several natural isolates of Bacillus strains namely 5B, 12B, 16B, 18 and 24B were grown on two different temperatures in submerged fermentation for the raw-starch-digesting a-amylases production. All strains except Bacillus sp. 18 produced more α-amylase on 37ºC. The hydrolysis of raw corn starch followed same pattern. Efficient hydrolysis was obtained with α-amylases from Bacillus sp. 5B, 12B, 16B and 24B grown on 37ºC and Bacillus sp. 18 grown on 50ºC. Zymography after isoelectric focusing shown that α-amylases were produced in multiple forms, from 2 to 6, depending on the strain when they were growing at 37 ºC, while growing at 50ºC induced only 1 or 2 isoforms. TLC analysis of hydrolysis products of raw corn and soluble starch by α-amylases revealed production of various mixtures of oligosaccharides. In most cases G3 was the most dominant product from soluble starch while G2, G3 and G5 were the main products of raw starch hydrolysis. This indicates that obtained a-amylases can be used for starch liquefying or short-chain-oligosaccharide forming, depending on what type of starch (raw or soluble) was used for the hydrolysis. [Projekat Ministarstva nauke Republike Srbije, br. 172048]

Keywords

• bacterial amylase
• raw starch digestion
• TLC
• zymogram