摘要
采用紫外线与亚硝基胍(NTG)两种诱变方法获得用于基因组重组的出发菌株,应用灭活的多亲原生质体再融合获得活性融合子的方法,有效地提高了基因组改组后的筛选效率。采用低pH值平板和碳酸钙平板连续筛选的方法,筛选得到干酪乳杆菌改组菌株,具有较强耐酸性能,够在pH3.6MRS平板上生长繁殖,产酸量为原始菌株的3.4倍,发酵温度提高到40℃,摇瓶发酵结果表明,改良菌株的代谢途径未发生变化。
In this study, wild-type Lactobacillus rhamnosus was treated respectively by ultraviolet （UV） irradiation and nitrosoguanidine （NTG） to obtain mutant strains, and then they were subjected to recursive protoplast fusing. The acid tolerance and thermotolerance of the wild-type Lactobacillus rhamnosus are improved by genome shuffling. A library that is more likely to yield positive results was created by using fusing the lethal protoplasts obtained from the strains treated by both UV irradiation and heat. After three rounds of genome shuffling, the strains that could grow at pH 3.6 were obtained. The L-lactic acid production is 3.4 times of that of the wild-type strain and the temperature is increased to 40 ℃. The results of shake-flask fermentation showed that the shuffled strains have the same pathway producing L-lactic acid as the wild-type one.
出处
《食品科学》
EI
CAS
CSCD
北大核心
2008年第10期395-398,共4页
Food Science
关键词
L-乳酸
干酪乳杆菌
基因组改组
L-lactic acid
LactobaciUus rhamnosus
genome shuffling
