耐酸性α-淀粉酶产生菌的筛选及其产酶条件优化

摘要

为了分离得到饲料用耐酸性α-淀粉酶的菌株,从食堂排污口取土样,筛选到一株耐酸(pH=4)且产α-淀粉酶的菌株,并对其形态特征、培养特征、生理生化特征、酶学性质及产酶条件进行研究。结果表明：菌体呈杆状,革兰氏染色阳性,胞内形成异染粒和PHB,接触酶、淀粉水解、卵磷脂酶试验呈阳性,反硝化试验、荧光色素呈阴性。根据菌体形态、菌落特征及部分生理生化特性,将其初步鉴定为芽孢杆菌属,即Bac illus sp.SD-1。通过单因素试验对菌株的最适产酶温度及pH进行优化,培养温度为43℃,pH为4.5,发酵60 h,酸性α-淀粉酶活力达到74.6 U/mL。%In order to obtain acid resistant strains producing α-amylase for the application in feed industrial field. Clear circle was used to initially screen desired strains at pH 4.SD-1 was chosen as experimental strain owning to its high-er ratio of dissolving circle diameter to colony diameter.Strain SD-1 was rod,G+.Test results of metachromatic granule staining,PHB,catalase,amylolysis,lecithinase were positive.Test results of denitrification and fluorchrome were negative. According to its cell and colony morphology,physiological and biochemical properties,strain SD-1 belongs to genus Bacil-lus,namely Bacillus sp.SD-1.Optimization of higherα-amylase production conditions:43℃,pH 4.5,fermentation for 60 h, the activity ofα-amylase was up to 74.6 U/mL.