甲基营养菌MB200中mutL基因的突变及高耐甲醇菌株的筛选  

Mutation of mutL gene in methylotrophic bacteria MB200 and screening of highly methanol-tolerant strains

作　　者：闻东明 黄罗冬 杨青山 申佩弘[1] WEN Dongming;HUANG Luodong;YANG Qingshan;SHEN Peihong(University of Guangxi for Life Science and Technology,Nanning 530004,China)

机构地区：[1]广西大学生命科学与技术学院,广西南宁530004

出　　处：《工业微生物》2020年第4期15-20,共6页Industrial Microbiology

摘　　要：甲基营养菌M.sp.MB200是本实验室保存的一株可以利用甲醇为碳源的甲基营养菌,具有利用甲醇作为底物生产L-丝氨酸的能力。提高其耐底物浓度的能力,有利于L-丝氨酸的转化。以M.sp.MB200野生菌株作为出发菌株,通过三亲本结合进行同源单交换构建突变修复基因mutL插入突变菌株MB200mTB,该突变株无法修复菌体在繁殖传代过程中产生的各种随机突变,以甲醇为碳源进行环境压力筛选,具有甲醇耐受突变的菌株可以在甲醇浓度不断升高的环境中生长,而其余突变方向菌株在高甲醇环境下不能生长,进而筛选出甲醇耐受方向的突变株。对耐高浓度甲醇的菌株使用三亲本结合回补mut L基因,得到了7株可以在甲醇浓度为7%的基础培养基中生长性状优异的突变株。在含7%甲醇的基础培养基中,MB200mHB1号突变株较出发菌株M.sp.MB200甲醇耐受性提升近4倍,菌体生长量增加2.2倍。Methanol is an important organic chemical raw material with low price and high carbon reduction.Methylobacterium sp.MB200 is a kind of methylotrophic bacteria preserved in our laboratory,which can use methanol as carbon source and has the ability to produce l-serine by using methanol as substrate.It is beneficial to the transformation of L-serine by improving its ability of tolerance to substrate concentration.MB200 wild strain was used as the starting strain to construct mutL insertion mutant through homologous single exchange by triparental mating.Random mutations were introduced by continuous passage and directed evolution.The mutant was screened by pressure with methanol as carbon source.Seven mutant strains with excellent growth characteristics were obtained in the basic medium with a methanol concentration of 7%.In the basic medium containing 7%methanol,the methanol tolerance of MB200 mHB1 mutant was nearly 4 times higher than that of the original MB200 strain,and the growth capacity of MB200 mHB1 mutant was 2.2 times higher than that of the original MB200 strain.

关 键 词：M.sp MB200 mutL插入突变 甲醇耐受 三亲本结合 

分 类 号：Q939.9[生物学—微生物学]