Laboratory metabolic evolution improves acetate tolerance and growth on acetate of ethanologenic Escherichia coli under non-aerated conditions in glucose-mineral medium
Laboratory metabolic evolution improves acetate tolerance and growth on acetate of ethanologenic Escherichia coli under non-aerated conditions in glucose-mineral medium
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DOI：
10.1007/s00253-012-4177-y
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发表时间：
2012-12-01
影响因子：
5
通讯作者：
Martinez, A.
中科院分区：
文献类型：
--
作者：
Fernandez-Sandoval, M. T.;Huerta-Beristain, G.;Martinez, A.
在这项工作中，大肠杆菌MG 1655被改造为生产乙醇，并在实验室过程中进化，以获得一种称为MS 04（E. coli MG 1655：Δ pflB，Δ adhE，Δ frdA，Δ xylFGH，Δ ldhA，PpflB：：pdc（Zm）-adhB（Zm），进化的）。菌株MS 04的生长和乙醇生产动力学在矿物培养基中测定，主要是在非通气条件下，在pH 7.0的不同浓度的乙酸钠存在下和在不同的酸性pH值和恒定浓度的乙酸钠（2g/l）下补充有葡萄糖。结果显示，在中等浓度的乙酸钠（2-10 g/l）下，除了对乙酸盐的高耐受性之外，比生长速率、细胞团形成和乙醇体积生产率增加，因为它能够在高达40 g/l的乙酸钠存在下生长并产生高产率的乙醇。Delta pflB进化菌株的基因组分析鉴定了27.3kb的染色体缺失在MG 1655 Delta pflB衍生菌株中产生改善的生长和乙酸盐耐受性。这种缺失包括与硝酸盐呼吸、烷基化DNA修复和编码孔蛋白C、细胞色素C、硫胺素和结肠酸的ompC基因的合成相关的基因。菌株MS 04有利于从含有乙酸盐的半纤维素水解产物生产乙醇。
In this work, Escherichia coli MG1655 was engineered to produce ethanol and evolved in a laboratory process to obtain an acetate tolerant strain called MS04 (E. coli MG1655: Delta pflB, Delta adhE, Delta frdA, Delta xylFGH, Delta ldhA, PpflB::pdc (Zm) -adhB (Zm) , evolved). The growth and ethanol production kinetics of strain MS04 were determined in mineral medium, mainly under non-aerated conditions, supplemented with glucose in the presence of different concentrations of sodium acetate at pH 7.0 and at different values of acid pH and a constant concentration of sodium acetate (2 g/l). Results revealed an increase in the specific growth rate, cell mass formation, and ethanol volumetric productivity at moderate concentrations of sodium acetate (2-10 g/l), in addition to a high tolerance to acetate because it was able to grow and produce a high yield of ethanol in the presence of up to 40 g/l of sodium acetate. Genomic analysis of the Delta pflB evolved strain identified that a chromosomal deletion of 27.3 kb generates the improved growth and acetate tolerance in MG1655 Delta pflB derivative strains. This deletion comprises genes related to the respiration of nitrate, repair of alkylated DNA and synthesis of the ompC gene coding for porin C, cytochromes C, thiamine, and colonic acid. Strain MS04 is advantageous for the production of ethanol from hemicellulosic hydrolysates that contain acetate.