High production of 2,3-butanediol from biodiesel-derived crude glycerol by metabolically engineered Klebsiella oxytoca M1.
High production of 2,3-butanediol from biodiesel-derived crude glycerol by metabolically engineered Klebsiella oxytoca M1.
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DOI：
10.1186/s13068-015-0336-6
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发表时间：
2015
影响因子：
6.3
通讯作者：
Um Y
中科院分区：
文献类型：
--
作者：
Cho S;Kim T;Woo HM;Kim Y;Lee J;Um Y
2,3-丁二醇（2,3-BDO）因其广泛的工业应用而成为一种很有前景的生物基化学品。先前关于微生物生产 2,3-BDO 的研究主要集中在糖发酵上。或者，生物柴油衍生的粗甘油可用作 2,3-BDO 生产的廉价资源；然而，甘油发酵中 1,3-丙二醇 (1,3-PDO) 的大量形成以及 2,3-BDO 的浓度、生产率和产量较低是其局限性。在这里，我们报告使用工程化的产酸克雷伯菌 M3 从粗甘油中高产 2,3-BDO，其中 pduC（编码甘油脱水酶大亚基）和 ldhA（编码乳酸脱氢酶）被删除，以减少 1,3-PDO 和乳酸的形成。在母株 K. oxytoca M1 的补料分批发酵中，粗甘油作为碳源在 2,3-BDO 生产（59.4 vs. 73.8 g/L）和副产物减少（1,3-PDO，8.9 vs. 3.7 g/L；乳酸，18.6 vs. 9.8 g/L）方面比纯甘油更有效。当双突变体用于纯甘油补料分批发酵时，细胞生长和甘油消耗显着增强，2,3-BDO 产量比亲本菌株高 1.9 倍（59.4 vs. 115.0 g/L），其中 1,3-PDO 6.9 g/L 和少量乳酸（0.7 g/L）。值得注意的是，当提供粗甘油时，双突变体显示出不含 1,3-PDO 的 2,3-BDO 产量，具有高浓度 (131.5 g/L)、生产率 (0.84 g/L/h) 和产量 (0.44 g/g 粗甘油)。这一结果是迄今为止甘油发酵中 2,3-BDO 产量的最高结果。通过破坏 K. oxytoca M1 中的 pduC 和 ldhA 基因，从甘油中生产 2,3-BDO 得到显着增强，并且通过使用双突变体和粗制甘油实现了不含 1,3-PDO 的 2,3-BDO 生产。本研究中获得的 2,3-BDO 产量与糖发酵生产的 2,3-BDO 相当，证明了使用粗甘油经济工业化生产 2,3-BDO 的可行性。本文的在线版本 (doi:10.1186/s13068-015-0336-6) 包含补充材料，可供授权用户使用。
2,3-Butanediol (2,3-BDO) is a promising bio-based chemical because of its wide industrial applications. Previous studies on microbial production of 2,3-BDO has focused on sugar fermentation. Alternatively, biodiesel-derived crude glycerol can be used as a cheap resource for 2,3-BDO production; however, a considerable formation of 1,3-propanediol (1,3-PDO) and low concentration, productivity, and yield of 2,3-BDO from glycerol fermentation are limitations. Here, we report a high production of 2,3-BDO from crude glycerol using the engineered Klebsiella oxytoca M3 in which pduC (encoding glycerol dehydratase large subunit) and ldhA (encoding lactate dehydrogenase) were deleted to reduce the formation of 1,3-PDO and lactic acid. In fed-batch fermentation with the parent strain K. oxytoca M1, crude glycerol was more effective than pure glycerol as a carbon source in 2,3-BDO production (59.4 vs. 73.8 g/L) and by-product reduction (1,3-PDO, 8.9 vs. 3.7 g/L; lactic acid, 18.6 vs. 9.8 g/L). When the double mutant was used in fed-batch fermentation with pure glycerol, cell growth and glycerol consumption were significantly enhanced and 2,3-BDO production was 1.9-fold higher than that of the parent strain (59.4 vs. 115.0 g/L) with 6.9 g/L of 1,3-PDO and a small amount of lactic acid (0.7 g/L). Notably, when crude glycerol was supplied, the double mutant showed 1,3-PDO-free 2,3-BDO production with high concentration (131.5 g/L), productivity (0.84 g/L/h), and yield (0.44 g/g crude glycerol). This result is the highest 2,3-BDO production from glycerol fermentation to date. 2,3-BDO production from glycerol was dramatically enhanced by disruption of the pduC and ldhA genes in K. oxytoca M1 and 1,3-PDO-free 2,3-BDO production was achieved by using the double mutant and crude glycerol. 2,3-BDO production obtained in this study is comparable to 2,3-BDO production from sugar fermentation, demonstrating the feasibility of economic industrial 2,3-BDO production using crude glycerol. The online version of this article (doi:10.1186/s13068-015-0336-6) contains supplementary material, which is available to authorized users.