常温常压等离子体诱变选育高产L-异亮氨酸大肠杆菌

旨在选育L-异亮氨酸高产大肠杆菌。以大肠杆菌K12(Met^-)为出发菌株,经常温常压等离子体(ARTP)诱变,通过微生物高通量液滴培养系统(MMC)筛选,以α-氨基丁酸(α-AB)抗性为筛选标记,得到一株高产L-异亮氨酸的突变菌株大肠杆菌NXU12,并对其遗传稳定性进行了研究。结果表明,出发菌株大肠杆菌K12(Met^-)经过ARTP诱变处理180 s后,通过单因素多水平实验、适应性进化实验、发酵培养复筛、遗传稳定性验证等选育出一株高产L-异亮氨酸诱变大肠杆菌NXU12。该菌株在发酵培养40 h后,L-异亮氨酸产量达到17.462 8 g/L,比原始菌株10.830 9 g/L提高61.23%,且遗传性状稳定。

Breeding High-yield L-isoleucine Escherichia coli by ARTP Mutagenesis

This work aims to breed high-yield L-isoleucine-producing Escherichia coli.Using E.coli K12(Met^-)as the original strain,regular temperature and atmospheric pressure plasma(ARTP)was for mutagenesis,combined with microbial high-throughput droplet culture system(MMC)was for screening,with α-aminobutane acid(α-AB)resistance was used as a selection marker to obtain a mutagenic E.coli NXU12 producing high yield of L-isoleucine and its genetic stability was studied.The results showed that after the original strain K12(Met^-)was subjected to ARTP mutagenesis for 180 s,a strain of high-yield L-isoleucine mutagenesis,E.coli NXU12,was selected through single-factor multi-level experiments,adaptive evolution experiments,fermentation culture re-screening,and genetic stability verification.After 40 hof fermentation and culture,the L-isoleucine yield of this strain reached 17.462 8 g/L,which was 61.23% higher than that by original strain 10.830 9 g/L,and the genetic traits were stable.