α- 淀粉酶产生菌的分离筛选及酶学性质研究

目的]获得在某些方面性能优良（如耐高温、耐强酸、耐强碱等）的α-淀粉酶产生菌。方法]对α-淀粉酶产生菌进行分离筛选,并对其酶学性质进行了研究。结果]从稀释样品涂布的淀粉筛选平板上筛选出10株有明显淀粉水解圈的单个菌株,又从中得到3株α-淀粉酶酶活力较高的菌株：X6、X8和X10。这3株菌的最适pH值均在中性范围内,最适温度均为60℃。Ca2＋能提高酶的热稳定性,X6和X8在Ca2＋浓度为0.02～0.04 mol/L时,酶的热稳定性最高;X10在Ca2＋浓度为0.03～0.04 mol/L时,酶的热稳定性最高;当Ca2＋浓度继续增大时,酶的热稳定性反而降低。结论]为满足不同行业对不同特征α-淀粉酶的需求提供了理论依据。

Studies on the Isolation and Screening of α-amylase Producing Strain and Their Enzymatic Properties

Objective] The aim was to obtain α-amylase producing strains with some excellent properties like high temperature resistance,strong acid resistance,strong alkali resistance,etc..Method] α-amylase producing strains were isolated and screened,furthermore their enzymatic properties were studied.Result] 10 strains with an obvious starch hydrolysis cycle were screened out from starch screening plate coated by diluted sample,from which 3 strains with higher α-amylase activity were screened out,that was X6,X8 and X10.As for X6,X8 and X10,their optimum pH values all belonged to neutral,and their optimum temperatures were all 60 ℃.Meanwhile,Ca2+ could increase their enzyme thermal stability.When the concentration of Ca2+ was 0.02-0.04 mol/L,the enzyme thermal stability of X6 and X8 reached the highest;When the concentration of Ca2+ was 0.03-0.04 mol/L,that of X10 reached the highest;When the concentration of Ca2+ was increased continuously,those of the 3 strains all decreased.Conclusion] The research provides theoretical basis for satisfying the demands of different industries for α-amylase with different characteristics.