应用基因组重排技术提高普那霉素产量

将普那霉素产生菌——始旋链霉菌ND-23的孢子和原生质体经紫外线诱变后获得高产突变菌株,其中高产突变株SP-S73的产量达到356 mg/L,比出发菌株提高了31%.在上述增产突变株中选取4株作为基因组重排的出发亲本,对它们进行了4轮基因组重排育种,筛选得到了高产重排菌株,其中1株重排菌株G-211的普那霉素产量为832 mg/L,比产量最高的亲本菌株提高了134%,比原始出发菌株ND-23(272 mg/L)提高了206%.通过研究高产菌株和出发菌株ND-23在5 L罐上的发酵过程,发现普那霉素产生菌的生物合成属于非生长耦合型；其高产菌株G-211在合成产物的时期对还原糖和氨基氮的消耗量均大于原始菌株ND-23,这些结果将为高产菌株发酵条件优化和发酵放大研究提供有价值的参考.

Enhanced production of pristinamycin fermentation by genome shuffling

A series of high pristinamycin-producing mutants were screened after spores and protoplasts of Streptomyces pristinaespiralis ND-23, a producer of pristinamycin, were treated by UV mutagenesis. The pristinamycin production of the highest producer mutant reached 356 mg/L, which was increased by 31% compared with that of the original strain. Genome shuffling was applied to improve pristinamycin production of Streptomyces pristinaespiralis by utilizing the four highest strains derived from the above UV mutants as the starting population. A recombinant Streptomyces pristinaespiralis G-211 with improved phenotype was obtained by four rounds of genome shuffling, and its production reached 832 mg/L, which was increased by 134% and 206% compared with that of the highest parent strain and the original strain, respectively. Fermentation experiments by Streptomyces pristinaespiralis G-211 and ND-23 were conducted in 5 L fermentor. Results show that the biosynthesis of pristinamycins is not coupled to cell growth of Streptomyces pristinaespiralis.The consumption rate of glucose and amino nitrogen of the strain G-211 is more rapid than that of the initial strain ND-23. The results can be useful for medium optimization and scale-up of pristinamycin fermentation.