α-葡萄糖苷酶高产菌株HB-9-5的选育及产酶条件的优化

Study on Screening and Fermentation Conditions of Highα-glucosidase-producing Strain HB-9-5

从土壤中筛选出一株高产α-葡萄糖苷酶的细菌HB-09-5,对其粗酶液进行研究发现,最适反应pH为6.0,最适反应温度为50℃,pH在4.0-7.0,温度在55℃以下保持酶活力相对稳定。通过对产酶条件进行优化,单因素试验表明,最佳碳源为可溶性淀粉,最佳氮源为牛肉膏,Mg2+和Ca2+对产酶有促进作用。优化发酵条件后,菌株HB-09-5产酶水平可达到20.95U/mL,比出发菌酶活提高了2.3倍。

A HB-09-5 strain with higher activity ofα-glucosidase was screened from soil.The results showed that enzyme had an optimum activity at 50℃and pH6.0.It was active below 55℃and stable at pHs ranging from 4.0 to 7.0.Through improving the conditions for the enzyme production,the single factor experiment showed that the optimal carbon source was soluble starch,and the optimal nitrogen source was beef extract.Theα-glucosidase was activated by Ca 2＋ and Mg 2＋ ion.After the fermentation medium was optimized,the enzyme activity arrived 20.95 U/mL,which was 2.3 times of the original strain.