凡纳滨对虾肠道益生菌的分离· 筛选· 鉴定

目的]获得具有拮抗常见病原菌活性、消化酶活性且具有安全性的凡纳滨对虾肠道内源性益生菌。方法]从健康凡纳滨对虾肠道中经过初步分离与纯化得到1 220株细菌,对分离的菌株进行拮抗试验,并对产蛋白酶、淀粉酶和脂肪酶能力进行定量和定性研究。对筛选的13株细菌进行了溶血试验和药敏试验,以评价其生物安全性。结果]共筛选出13株抑菌活性强、产酶能力强且产酶种类多的菌株,最终确定了2株候选益生菌。菌株的16 S rDNA分子鉴定及Biolog系统鉴定结果表明,细菌3号与霍氏肠杆菌(Enterobacter hormaechei strain WW2,JN993998.1)相似性达到98%,细菌6号与乳酸菌(Lactic acid bacterium ZJGS0109,KC748440.1)相似性达100%。结论]研究结果为今后益生菌制剂的开发和应用奠定了基础。

Isolation,Screening and Identification of Intestinal Probiotics of Litopenaeus vannamei

Objective]To obtain endogenous probiotics in the intestine of Litopenaeus vannamei with antagonistic activity to common pathogenic bacteria,digestive enzyme activity and safety.Method]1 220 strains of bacteria were preliminarily separated and purified from the intestine of healthy L.vannamei to make an antagonistic test.The quantitative and qualitative experiments were made on the abilities of producing protease, amylase and lipase of the separated strains.The hemolysis test and drug susceptibility test were made on 13 screened strains and its biosecurity was evaluated.Result]13 strains with strong antibacterial activity,high enzyme-producing activity and many kinds of enzyme were screened out, and finally 2 strains of candidate probiotics were determined.The results of 16S rDNA molecular identification and Biolog system identification showed that the similarity between No.3 strain and Enterobacter hormaechei strain WW2(JN993998.1)was 98%,and the similarity between No. 6 strain and Lactic acid bacterium ZJGS0109(KC748440.1)was 100%.Conclusion]The research results laid the foundation for the develop-ment and application of probiotic preparations in future.