Improvement of Hydrogen Production Yield by Rebalancing NADPH/NADH Ratio in a Recombinant Escherichia coli
Improvement of Hydrogen Production Yield by Rebalancing NADPH/NADH Ratio in a Recombinant Escherichia coli
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DOI：
10.1166/jno.2011.1182
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发表时间：
2011-08-01
影响因子：
0.6
通讯作者：
Park, Jong Moon
中科院分区：
文献类型：
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作者：
Cho, Han-Saem;Kim, Young Mi;Park, Jong Moon
与甲酸氢裂解酶(FHL)相比，NAD(P)H或铁氧还蛋白依赖的产氢途径在提高其产量方面具有巨大的潜力。为了通过这一途径提高产氢效率，除了通过减少竞争途径来提高NAD(P)H池外，基于辅因子偏好的NADPH/NADH重新平衡是重要的。NADPH：铁还蛋白氧化还原酶与[FeFe]-氢酶偶联较好地利用NADPH作为电子供体。因此，需要指导NADPH来提高产氢率。为了平衡NADPH/NADH比率，烟酰胺核苷酸转氢酶起着关键作用，而大肠杆菌有两种转氢酶，PntAB和SthA。在本研究中，构建了几个重组体，以上调pntAB或下调竞争/DHA缺失的大肠杆菌表达[FeFe]-氢酶系统中的sthA。结果，在pntAB过表达和sthA缺失的菌株中观察到大约3.9倍的产氢量。因此，通过转氢酶工程将IDHA下调和NADPH/NADH比值再平衡相结合，可以提高依赖NADPH或铁氧还蛋白的产氢途径的产氢量。
The NAD(P)H- or ferredoxin-dependent hydrogen production pathway is known to have a huge potential for improving its production yield compared to the formate hydrogen lyase (FHL) route. To improve the hydrogen production yield through this pathway, rebalancing the NADPH/NADH ratio based on the cofactor preference is important, in addition to enhancing the NAD(P)H pool by reducing the competing pathways. NADPH:ferredoxin oxidoreductase coupled with [FeFe]-hydrogenase preferably utilizes NADPH as an electron donor. Therefore, directing NADPH should be required to improve the hydrogen production yield. For balancing the NADPH/NADH ratio, nicotinamide nucleotide transhydrogenase has a key role, and Escherichia coli has the two transhydrogenases, PntAB and SthA. In this study, several recombinants were constructed to up-regulate pntAB or to down-regulate sthA in the competing-/dhA-deleted E. coli expressing [FeFe]-hydrogenase system. As a result, an about 3.9-fold increased hydrogen yield was observed in the pntAB-overexpressed and sthA-deleted strain. Therefore, the combination of IdhA down-regulation and NADPH/NADH ratio rebalancing via transhydrogenase engineering can improve the hydrogen production yield in the NADPH- or ferredoxin-dependent hydrogen production pathway.