Optimization of ethylene glycol production from (D)-xylose via a synthetic pathway implemented in Escherichia coli.
Optimization of ethylene glycol production from (D)-xylose via a synthetic pathway implemented in Escherichia coli.
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通过（d） - 木糖通过大肠杆菌实施的合成途径优化乙二醇生产。
DOI：
10.1186/s12934-015-0312-7
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发表时间：
2015-09-04
影响因子：
6.4
通讯作者：
Walther T
中科院分区：
文献类型：
--
作者：
Alkim C;Cam Y;Trichez D;Auriol C;Spina L;Vax A;Bartolo F;Besse P;François JM;Walther T
乙二醇(EG)是一种大宗化学品，主要用作防冻剂和合成塑料的原料。目前，商用EG的生产完全依赖于利用化石资源进行化学合成。从可再生资源中生化生产乙二醇可能更具可持续性。在此，描述了一种合成途径，该合成途径通过(D)-木糖异构酶、(D)-木糖-1-激酶、(D)-木糖-1-磷酸缩醛酶和乙醇醛还原酶的作用在大肠杆菌中产生EG。这些反应分别由内源性木糖异构酶(XylA)、异源表达的人己糖激酶(KHK-C)和醛缩酶(Aldo-B)以及内源性乙醇醛还原酶活性(YQhD编码)催化。通过删除编码(D)-木糖-5激酶(XylB)和乙醇醛脱氢酶(Alda)的基因，以及过表达候选的乙醇醛还原酶YqhD、GldA和FucO，对生产菌株进行了优化。在摇瓶培养条件下，FucO高产菌株产乙二醛的摩尔产量为0.94g/L，好氧条件下在受控生物反应器中的乙二醛产量为20g/L，摩尔产量为0.91g/(L.h)，产率为0.37g/(L.h)。我们已经证明了在大肠杆菌中通过合成途径从(D)-木糖合成EG的可行性，其产率约为理论产率的90%。本文的在线版本(doi：10.1186/s12934-0150312-7)包含补充材料，授权用户可以使用。
Ethylene glycol (EG) is a bulk chemical that is mainly used as an anti-freezing agent and a raw material in the synthesis of plastics. Production of commercial EG currently exclusively relies on chemical synthesis using fossil resources. Biochemical production of ethylene glycol from renewable resources may be more sustainable. Herein, a synthetic pathway is described that produces EG in Escherichia coli through the action of (d)-xylose isomerase, (d)-xylulose-1-kinase, (d)-xylulose-1-phosphate aldolase, and glycolaldehyde reductase. These reactions were successively catalyzed by the endogenous xylose isomerase (XylA), the heterologously expressed human hexokinase (Khk-C) and aldolase (Aldo-B), and an endogenous glycolaldehyde reductase activity, respectively, which we showed to be encoded by yqhD. The production strain was optimized by deleting the genes encoding for (d)-xylulose-5 kinase (xylB) and glycolaldehyde dehydrogenase (aldA), and by overexpressing the candidate glycolaldehyde reductases YqhD, GldA, and FucO. The strain overproducing FucO was the best EG producer reaching a molar yield of 0.94 in shake flasks, and accumulating 20 g/L EG with a molar yield and productivity of 0.91 and 0.37 g/(L.h), respectively, in a controlled bioreactor under aerobic conditions. We have demonstrated the feasibility to produce EG from (d)-xylose via a synthetic pathway in E. coli at approximately 90 % of the theoretical yield. The online version of this article (doi:10.1186/s12934-015-0312-7) contains supplementary material, which is available to authorized users.