常压室温等离子诱变选育L-色氨酸高产菌株

Breeding of L-tryptophan high-yield strain by ARTP mutagenesis

为了提升发酵法产L-色氨酸的生产效率,使用常压室温等离子(atmospheric and room temperature plasma,ARTP)诱变育种技术,并结合结构类似物抗性定向筛选的方法,选育高产色氨酸菌株。将出发菌Escherichia coli AC-1042经过ARTP诱变处理后,在抗性培养基平板上筛选具有5-甲基色氨酸、对氟苯丙氨酸抗性的突变菌株,选取产酸高、遗传稳定的菌株重复进行ARTP诱变处理和抗性筛选,不断提高菌株对结构类似物的抗性水平。经过多次ARTP诱变处理和抗性筛选,获得1株色氨酸高产菌株ACTRP104,经过30 L发酵罐培养44 h后L-色氨酸质量浓度可以达到61.65 g/L,葡萄糖转化率达到20.64%,比出发菌分别提高了20.69%和17.81%。结果表明,ARTP诱变和结构类似物抗性筛选相结合,可以有效地获得色氨酸高产突变菌株,大大提高色氨酸的发酵生产技术水平,获得的色氨酸高产菌株ACTRP104具有较好的工业化应用前景。

To improve the efficiency of L-tryptophan production,atmospheric and room temperature plasma(ARTP)mutagenesis combined with analogue resistance screening was used to obtain high-yield L-tryptophan production strain.Escherichia coli AC-1042 was mutated by ARTP mutagenesis,and the L-tryptophan genetic stable high-yield strain was selected by 5-methyltryptophan(5-MT)and p-fluorophenylalanine(PFP)resistance.After multiple ARTP mutagenesis processing and improving the analogue resistance screening,a genetic stable high-yield tryptophan strain ACTRP104 was obtained.The tryptophan mutant ACTRP104 produced 61.65 g/L L-tryptophan at a yield of 20.64%of glucose in the 30 L fermentation tank at 44 h,which was increased by 20.69%and 17.81%compared with the original strain,respectively.These results suggested that it was effective to improve the production capacity of tryptophan strains by combining of ARTP mutagenesis with analogue resistance screening.The tryptophan high-yield mutant ACTRP104 has a great potential for industrial application.