离子注入诱变植物乳杆菌选育CLA高产突变株的研究

以A6-1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1×1013、3×1013、5×1013、8×1013、10×1013、30×1013、50×1013、80×1013、100×1013ion/cm2,真空度为10-3Pa。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30×1013ions/cm2～50×1013ions/cm2之间,此时菌体的存活率在20%～35%之间。综合考虑存活率、总突变率、正突变率和突变幅度等因素,推荐30×1013ions/cm2作为离子注入植物乳杆菌的适宜诱变剂量。从所有的注入处理中挑选CLA转化能力提高了50%以上的突变株进行传代稳定性试验,发现F菌株经8次传代后产CLA的稳定性最好。该突变株各代的产量平均为162.5μg/ml,比出发菌株提高了69.87%,将此突变菌株命名为A6-1F。

SCREENING OF A Lactobacillus plantarum MUTANT WITH HIGH CLA PRODUCTIVITY INDUCED BY N~+ IMPLANTATION

The initial lactic acid bacteria strain A6-1 was treated by N~+ ions implantation of 50 keV with doses of 1 × 10~(13).3×10~(13),5 × 10~(13),8 × 10~(13),10 × 10~(13),30 × 10~(13),50 × 10~(13),80 × 10~(13),and 100 × 10~(13) ions/cm~2.The survival curve showed a saddle model,and the high survival rate was 20%～35%from the treatments of 30 × 10~(13) ions/cm~2 and 50 × 10~(13) ions/cm~2 implantation.Considering the survival rate,positive mutation and range of mutation rate,N~+ ions implantation of 30 × 10~(13)ions/cm~2 was recommended for mutation breeding of lactic acid bacteria.Selected mutants with high ability of producing CLA after fermentation.Generic stable was observed until 8 generations of F mutant,and average yield of CLA Was 162.5 μg/ml,which Was 69.87% higher than the original stain.F mutant was named A6-1F.