摘 要：为了获得高产马铃薯生淀粉糖化酶的菌株，本实验从土壤中分离得到菌株86株, 并对这些产酶菌株进行了产酶的初步测定，选出一株产酶量较高的strain（M55）进行进一步的实验。通过单因素实验和正交实验对M55的发酵条件进行了优化最后确定最佳发酵培养基组成为：糊化马铃薯淀粉0。2%、氯化铵0。3%、鱼粉蛋白胨0。2%、K2HPO4 0。1%、NaCl 0。1%、(NH4)SO4 0。2%、K2HPO4 0。15%、MgSO4·7H2O 0。05%、FeSO4·7H2O 0。001%、CaCl2 0。01%。最后通过硫酸铵对酶进行初步的纯化，同时对酶的性质进行了研究，发现本霉菌所产生的淀粉糖化酶在较宽泛的pH值下酶活都保持较高，且最适pH为5。0，酶发挥催化作用的最适温度在40℃，镁离子对酶活具有最高的促进作用。90738

毕业论文关键词：生淀粉糖化酶，菌种筛选，发酵优化，酶学性质

Abstract: In order to obtain potato raw starch-digesting glucoamylase high yield strains，86 strains of glucoamylase-producing strains were isolated from soil。We have selected a higher yield of (M55) for further experiments by made a preliminary determination of these enzymes on level of producing enzyme in this experiment。 The fermentation conditions of glucoamylase-producing strain were optimized by single factor experiment and orthogonal experiment，we have determined the optimal fermentation conditions that 0。2% Gelatinized potato starch, 0。3% ammonium chloride, 0。2% Fish meal peptone, 0。1% K2HPO4, 0。1% NaCl, 0。2% (NH4)SO4, 0。15% K2HPO4, 0。05% MgSO4·7H2O, 0。001% FeSO4·7H2O , 0。001% CaCl2。 The enzyme was purified by ammonium sulfate, and the properties of the enzyme were studied,  the enzyme activity of glucoamylase all was higher under a wide range of pH values and the optimum pH was 5。0。 The optimum temperature of the enzyme was 40℃。 Under certain conditions, the activity of enzyme was promoted by Magnesium ion。源G于J优L尔V论N文M网WwW。youeRw。com 原文+QQ75201`8766

Keywords: Raw Starch Glucoamylase, Screening of strains, Fermentation optimization,  Enzymatic  properties

目录

1  前言 5

2  材料与方法 5

2。1  材料 5

2。1。1  菌种 6

2。1。2  培养基 6

2。2  方法 6

2。2。1  菌株筛选步骤 6

2。2。2  碳源优化 6

2。2。3  无机氮源优化 6

2。2。4  有机氮源优化 7

2。2。5  正交试验 7

2。2。6  酶活测定 7

2。2。7  最适pH的测定 7

2。2。8  最适温度的测定 7

2。2。9  金属离子对酶活影响的测定 7

3  结果与讨论 7

3。1  菌株筛选结果 7

3。2  发酵优化结果 8

3。2。1  不同碳源对酶活的影响 8

3。2。2   不同无机氮源对酶活的影响 8

3。2。3  不同有机氮源对酶活的影响 9

3。3  正交试验结果