高产淀粉酶菌株的筛选及产酶条件优化的探究

Study of the screening and optimizing enzyme-producing conditions of high amylase-producing bacterial strains

目的:从土壤中分离筛选高产淀粉酶菌株,进行产酶条件优化,提高酶产量。方法:通过比较水解圈与菌落的直径比值大小、碘比色法及DNS显色法所测酶活性高低,从土壤中分离筛选到高产淀粉酶的菌株;通过菌落形态、镜下观察、生化特性对该菌株进行鉴定;从氮源、碳源两方面优化产酶条件,并测定酶促反应的最适温度和pH。结果:从土壤中筛选到一株高产的淀粉酶菌株,其D/d为4.20,酶活性经碘比色法测得为347.2U,DNS显色法测得为1906.2 U/L。经鉴定此菌株为地衣芽孢杆菌。该菌株产酶的最适氮源浓度为2.50%、碳源浓度为0.35%,酶促反应的最适温度为45℃,最适pH为7.0。结论:该菌株为地衣芽孢杆菌,是产淀粉酶的好材料,具有一定的应用开发前景。

Objective：To isolate and screen high amylase-producing bacterial strains from the soil and optimize its enzyme-producing conditions to increase the yield of enzyme.Methods： High amylase-producing bacterial strains were isolated from the soil and screened by the enzyme activity analyzed from the ratio of the diameter of the hydrolytic circle to the diameter of the colony,iodine colorimetry and DNS colorimetry;The bacterial strains were identified by colonial morphology,microscopic observation and biochemical characteristics;enzyme-producing conditions were optimized by carbon and nitrogen concentrations and optimized temperature and pH of the enzyme catalyzed reaction were detected as well.Results： One high amylase-producing bacterial strain was isolated from the soil,its D/d was 4.20,enzyme activity was 347.2 U by iodine colorimetry and 1906.2 U/L by DNS colorimetry.This strain was identified as Bnfillus Licheniformis. As for the optimized enzyme-producing conditions,the optimized nitrogen concentration was 2.50%,carbon concentration was 0.35%,enzyme catalyzed reaction temperature was 45℃ and pH was 7.0.Conclusion： The bacteria isolated was Bnfillus Licheniformis which was one kind of good material for amylase-producing and had good future for application and development.