复合诱变法选育生产乳果糖高产菌株的研究复合诱变法选育生产乳果糖高产菌株的研究

Study on breeding of high-yield strains for production of lactulose by compound mutation

选育生产乳果糖的高产菌株,为生物法(酶法)合成乳果糖提供技术保障。以乳酸克鲁维酵母变种(JN-187)为出发菌,经紫外线诱变选育出水解活性最高的JU74-09突变菌株;然后以JU74-09菌株为出发菌,经亚硝基胍(NTG)诱变选育出转糖基活性最高的JN91-08突变菌株;该菌株经7次传代实验,显示出良好的遗传稳定性。说明紫外线诱变与亚硝基胍(NTG)复合诱变是一种行之有效的用于生产乳果糖菌株选育的诱变方法。

High-yield strains for production of lactulose were bred by compound mutation, with a view of providing technical support for the biological （enzymatic） synthesis of lactulose. By using Kluyveromyceslactis （JN-187） as the original strain, UV mutagenesis was performed to breed Mutant Strain JU74-09 with the highest hydrolysis activity; then, with Mutant Strain JU74- 09 as the original strain, nitrosoguanidine（NTG） mutagenesis was performed to breed Mutant Strain JN91-08 with the highest transglycosylation activity. The results of 7 passage experiments showed that Mutant Strain JN91-08 had good genetic stability. All these proved that UV mutagenesis combined with nitrosoguanidine（NTG） mutagenesis is an effective mutation method of breeding strains for production of lactulose.