PEP群易位
色氨酸
大肠杆菌
化学
发酵
生物化学
工业发酵
食品科学
磷酸烯醇丙酮酸羧激酶
氨基酸
酶
基因
作者
Tao Wu,Jinjin Zhao,Xianjun Mao
出处
期刊:PubMed
日期:2017-11-25
卷期号:33 (11): 1877-1882
被引量:5
标识
DOI:10.13345/j.cjb.160460
摘要
L-tryptophan, one of the aromatic amino acids, is widely used in the fields of medicine, food and feed additives. The phosphoenolpyruvate-carbohydrate phosphotransferase system (PTS) plays an important role in glucose transport and phosphorylation in Escherichia coli. PTS-mediated regulation dominates the carbohydrates' uptake and metabolism in E. coli. We constructed L-tryptophan-producing bacteria containing two typical PTS mutations (ptsHIcrrglf⁻ glk⁺ and ptsG⁻) by Red homologous recombination system, and studied in 50 L jar fermenter using fed-batch fermentation. Both PTS system mutants had a great impact on the biomass (increasing 47.0% and 17.6%, respectively), L-tryptophan production (increasing 25.9% and 9.4%, respectively), glucose conversion rate (increasing 26.5% and 17.4%, respectively) and byproduct acetic acid generation (slightly increased and decreased,respectively).L-色氨酸是芳香族氨基酸的一种,被广泛应用于医药、食品和饲料等领域。大肠杆菌磷酸烯醇式丙酮酸-糖磷酸转移酶系统 (PTS 系统) 在葡萄糖转运和磷酸化过程中起重要作用,是糖代谢基因表达调控的核心。利用Red 同源重组系统,构建包含两类典型PTS 系统突变 (ptsHIcrr⁻ glf-glk⁺和ptsG⁻) 的L-色氨酸生产菌,并对相关菌株进行补料分批发酵研究。结果表明,不同类型PTS 系统突变对菌体生长、L-色氨酸产量、糖酸转化率及副产物生成均有较大影响。与出发菌相比,ptsHIcrr⁻ glf-glk⁺突变株最高OD600 达到125,提高47.0%,产酸38.5 g/L,提高25.9%,糖酸转化率16.7%,提高26.5%,乙酸生成略有增加;ptsG⁻突变株最高OD₆₀₀ 达到100,提高17.6%,产酸33.4 g/L,提高9.4%,糖酸转化率15.5%,提高17.4%,乙酸生成略有减少。对葡萄糖转运系统的进一步研究将为大肠杆菌合成L-色氨酸效率的提升提供帮助。.
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