Wang Yuhua, Li Yan, Pei Xiaolin, Yu Lei, Feng Yan
Key Laboratory for Molecular Enzymology and Engineering of Ministry of Education, Jilin University, 2519 Jiefang Road, Changchun 130023, PR China.
J Biotechnol. 2007 May 1;129(3):510-5. doi: 10.1016/j.jbiotec.2007.01.011. Epub 2007 Jan 25.
Genome shuffling is an efficient approach for the rapid improvement of industrially important microbial phenotypes. Here we improved the acid tolerance and volumetric productivity of an industrial strain Lactobacillus rhamnosus ATCC 11443 by genome shuffling. Five strains with subtle improvements in pH tolerance and volumetric productivity were obtained from the populations generated by ultraviolet irradiation and nitrosoguanidine mutagenesis, and then they were subjected for recursive protoplast fusion. A library that was more likely to yield positive colonies was created by fusing the lethal protoplasts obtained from both ultraviolet irradiation and heat treatments. After three rounds of genome shuffling, four strains that could grow at pH 3.6 were obtained. We observed 3.1- and 2.6-fold increases in lactic acid production and cell growth of the best performing at pH 3.8, respectively. The maximum volumetric productivity was 5.77+/-0.05 g/lh when fermented with 10% glucose under neutralizing condition with CaCO(3), which was 26.5+/-1.5% higher than the wild type.
基因组重排是一种有效提高具有工业重要性的微生物表型的方法。在此，我们通过基因组重排提高了工业菌株鼠李糖乳杆菌ATCC 11443的耐酸性和体积产率。通过紫外线照射和亚硝基胍诱变产生的群体中获得了五株在pH耐受性和体积产率方面有细微改善的菌株，然后对它们进行递归原生质体融合。通过融合从紫外线照射和热处理获得的致死原生质体，创建了一个更有可能产生阳性菌落的文库。经过三轮基因组重排后，获得了四株能够在pH 3.6下生长的菌株。我们观察到在pH 3.8时，表现最佳的菌株的乳酸产量和细胞生长分别增加了3.1倍和2.6倍。在用10%葡萄糖在有CaCO₃的中和条件下发酵时，最大体积产率为5.77±0.05 g/lh，比野生型高26.5±1.5%。
