Fine-tuning of NADH oxidase decreases byproduct accumulation in respiration deficient xylose metabolic Saccharomyces cerevisiae.
Fine-tuning of NADH oxidase decreases byproduct accumulation in respiration deficient xylose metabolic Saccharomyces cerevisiae.
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微调 NADH 氧化酶可减少呼吸缺陷木糖代谢酿酒酵母中副产物的积累
DOI：
10.1186/1472-6750-14-13
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发表时间：
2014-02-14
影响因子：
3.5
通讯作者：
Bao X
中科院分区：
文献类型：
--
作者：
Hou J;Suo F;Wang C;Li X;Shen Y;Bao X
有效利用木质纤维素原料中的所有可用碳是生产经济上可行的生物燃料的主要障碍。此前，为了实现木糖利用，我们将辅因子依赖性木糖还原酶（XR）和木糖醇脱氢酶（XDH）途径或辅因子非依赖性木糖异构酶（XI）途径引入酿酒酵母中。所得菌株高效代谢木糖。然而，在这两种途径重组菌株中，辅因子失衡导致副产物甘油和/或木糖醇的积累并降低了乙醇生产效率。在本研究中，我们将乳酸乳球菌中的 NADH 氧化酶引入 XI 和 XR-XDH 途径重组菌株中。为了减少副产物积累，同时维持木糖代谢，我们通过比较不同启动子和质粒控制下的表达来优化 NADH 氧化酶的表达水平。在重组 XI 菌株中，NADH 氧化酶以不同水平表达，并受到 2 μ 质粒中的 GPD2 启动子或 TEF1 启动子的调节。 GPD2启动子控制下的表达使甘油产量减少84%，乙醇产量和比生长率分别增加8%和12%。相反，在重组XR-XDH菌株中，这样的表达水平不足以有效地减少副产物的积累。因此，测试了更高的 NADH 氧化酶表达水平。在着丝粒质粒中 TEF1 启动子控制下表达 NADH 氧化酶的菌株中，木糖醇和甘油产量分别减少了 60% 和 83%，而没有显着影响木糖消耗。通过微调 NADH 氧化酶表达，我们减少了重组 XI 和 XR-XDH 木糖代谢酵母菌株中甘油或/和木糖醇的产量。最佳 NADH 氧化酶表达水平取决于代谢途径。类似的辅因子工程策略可以最大限度地提高其他氧化还原依赖性代谢物的产量。
Efficiently utilizing all available carbon from lignocellulosic feedstock presents a major barrier to the production of economically feasible biofuel. Previously, to enable xylose utilization, we introduced a cofactor-dependent xylose reductase (XR) and xylitol dehydrogenase (XDH) pathway, or a cofactor-independent xylose isomerase (XI) pathway, into Saccharomyces cerevisiae. The resulting strains metabolized xylose with high efficiency. However, in both pathway recombinant strains, the cofactor imbalance caused accumulation of the byproducts glycerol and/or xylitol and reduced the ethanol production efficiency. In this study, we introduced NADH oxidase from Lactococcus lactis into both XI and XR-XDH pathway recombinant strains. To reduce byproduct accumulation while maintaining xylose metabolism, we optimized the expression level of NADH oxidase by comparing its expression under the control of different promoters and plasmids. In recombinant XI strains, NADH oxidase was expressed at different levels, regulated by the GPD2 promoter or TEF1 promoter in the 2 μ plasmid. The expression under the control of GPD2 promoter decreased glycerol production by 84% and increased the ethanol yield and specific growth rate by 8% and 12%, respectively. In contrast, in the recombinant XR-XDH strains, such expression level was not efficient enough to decrease the byproduct accumulation. Therefore, higher NADH oxidase expression levels were tested. In the strain expressing NADH oxidase under the control of the TEF1 promoter in the centromeric plasmids, xylitol and glycerol production were reduced by 60% and 83%, respectively, without significantly affecting xylose consumption. By fine-tuning NADH oxidase expression, we decreased the glycerol or/and xylitol production in both recombinant XI and XR-XDH xylose-metabolizing yeast strains. The optimal NADH oxidase expression levels depend on metabolic pathways. Similar cofactor engineering strategies could maximize the production of other redox dependent metabolites.
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影响因子：
8.4
作者：
Hou, Jin;Lages, Nuno F.;Vemuri, Goutham N.
通讯作者：
Vemuri, Goutham N.
最大限度地减少工业乙醇酵母中的甘油合成而不影响其发酵性能
影响因子：
8.4
作者：
Guo, Zhong-peng;Zhang, Liang;Shi, Gui-yang
通讯作者：
Shi, Gui-yang
影响因子：
6.3
作者：
Hector RE;Dien BS;Cotta MA;Mertens JA
通讯作者：
Mertens JA
影响因子：
4.4
作者：
Lee, Sun-Mi;Jellison, Taylor;Alper, Hal S.
通讯作者：
Alper, Hal S.
影响因子：
6.4
作者：
Pagliardini J;Hubmann G;Alfenore S;Nevoigt E;Bideaux C;Guillouet SE
通讯作者：
Guillouet SE