重离子束辐照选育高产植物乳酸菌

摘要

12C6+ ion beam was used to irradiate strains of Lactobacillus plantarum JTL, and the results showed that the strain could get the highest positive mutation rate and lethality with 34.4% and 80% at the optimal absorbed dose of 300 Gy. The strains which could produce higher lactic acid were screened by selective MRS mediums and fermentation experiments. Finally, three mutations JTL2, JTL3 and JTL5 were obtained through the two screening steps of selecting plate and fermentation, and the contents of lactic acid in this three fermentation broth were greater than the original strain by 41.29% to 49.64%. The pass-generation test indicated that the heredity character of these mutations were stable. It is demonstrated that the lactic acids produced byLactobacillus plantarum JTL were remarkably improved, and heavy ion beam is an efficient radiation resource for microorganism breeding.%采用重离子束12C6+对乳酸菌出发菌株JTL进行辐照选育.确定吸收剂量300 Gy时最优,在该吸收剂量下,出发菌种的正突变率和致死率均达到最高,分别为34.4%、80%.通过酸斑法初筛和发酵复筛法,选育出高产酸的3株突变菌株(JTL2、JTL3、JTL5),其发酵液中乳酸含量比出发菌株JTL提高了41.29%~49.64%.同时,经过传代实验证实,3株菌株具有良好的遗传稳定性.研究表明,利用重离子束12C6+辐照处理乳酸菌可以得到高产酸的突变菌株,诱变效果显著.