产CLA植物乳杆菌P8的离子束诱变与筛选

THE LNDUCEMENT BY N^+ LON BEAM LMPLANTATION AND SCREENING OF A CLA PRODUCING LACTOBACILLUS PLANTARUM P8

本实验以植物乳杆菌P8为出发菌株,采用N+离子注入的方法进行诱变处理,注入能量为50keV,注入剂量为30、50、70、901、10、1301、50、1701、90×2.6×1013N+/cm2。结果显示,菌体的存活率随离子注入剂量的增加呈"马鞍型"曲线,"鞍脊"出现在70×2.6×1013N+/cm2～110×2.6×1013N+/cm2之间,此时菌体的存活率在21%～50%之间。综合考虑存活率、总突变率和突变幅度等因素,推荐90×2.6×1013N+/cm2作为离子注入植物乳杆菌P8的适宜诱变剂量。此菌株经N+离子束诱变,得到产共轭亚油酸(Conjugated linoleic acid,CLA)正突变菌株共36株,负突变菌株共66株,其中最高产CLA正突变菌株CLA浓度为0.2751mg/ml,转化率为27.51%。最低产CLA负突变株CLA浓度为0.0330mg/ml,转化率为3.30%。菌株的遗传稳定性正在进一步鉴定,若可以稳定遗传,将为研究植物乳杆菌P8产CLA的分子机理和生产出营养价值更高的保健食品奠定基础。

The initial lactobacillus plantarum P8 was treated by N＋ ions implantation of 50 keV with doses of 30,50,70,90,110,130,150,170,190×2.6×1013N＋/cm2.The survival curve showed asaddle model,and the high survival rate was 21 %~50 % from the treatments of 70×2.6×1013N＋/cm2 and 110 ×2.6×1013N＋/cm2 implantation.Considering the survival rate,positive mutation and range of mutation rate,N＋ implantation of 90×2.6×1013 N＋/cm2 was recommended for mutation breeding of lactobacillus plantarum.After the strain was induced by N＋ ion beam,the total number of positive mutants is 36 and the total number of negative mutants is 66,in which the most CLA productive mutant,the CLA concentration is 0.2751 mg/ml,the LA conversion rate is 27.51%.in which the lowest CLA productive mutant,the CLA concentration is 0.0330 mg/ml,the LA conversion rate of them is 3.30%.Genetic stability of the mutants are further identified,if possible,it will be able to lay the foundation for studying the molecular mechanism of lactobacillus plantarum producing CLA and producing higher nutritional value and health food.