Electricity active cells (EAC) generate electrons by organic substrate metabolism and transfer them through extracellular transport to an electrode surface in Microbial fuel cell (MFCs). Therefore, genetic modifications that increase the amount of electrons in EAC is one of feasibilities to optimize the electricity power output of MFCs.
Intracellular redox state of electricity active cells (EAC) is one of the most important physiological traits of extracellular electron transfer efficiency. In particular, the NAD<sup>+</sup>(H) pool size plays a central role of most metabolic pathways. By overexpressing the NAD synthetase, encoded be gene nadE and catalyzes the final step in de novo synthesis and salvage pathway of NAD biosynthesis (Fig. 1), the NAD+ level is increased thereby up-regulating genes whose products catalyze NADH synthesis. Therefore the augmented pool size of NAD<sup>+</sup>(H) result in promotion of NADH(the carrier of electrons)level, leading to high generation of intracellular releasable electrons and better electricity performance of EAC. <sup>[1]</sup>
<strong>Fig. 1 De novo synthesis and salvage pathway of NAD biosynthesis.</strong>
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<h4>HUST-China 2023</h4>
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We codon optimized the sequence of nadE for <i>S. oneidensis</i> MR-1 and determined its effect on intracellular NAD(H/+) concentration when co-expressed with nadD[BBa_K4595014], nadM[BBa_K4595015], and the experimental results proved that it could effectively increase the intracellular NAD(H/+) concentration.
<figcaption>Fig.2 The NAD(H/+) concentration of <i>S. oneidensis</i> MR-1, <i>S. oneidensis</i> MR-1(ycel-pncB), <i>S. oneidensis</i> MR-1(nadE-nadD-nadM).</figcaption>
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We Compared to the wild type, the total amount of NAD(H/+) in <i>S. oneidensis</i> MR-1(nadD-nadE-nadM) increased by 27.34%. This indicates that, <i>S. oneidensis</i> MR-1(nadD-nadE-nadM) facilitates more efficient electron transfer.
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Recent studies have proved that the intracellular redox state of EAC is one of the most important physiological traits of extracellular electron transfer efficiency. Particularly, the NAD+(H) pool size plays a central role of most metabolic pathways. In this study, we aim that, overexpression of gene nadE which encodes a NAD synthetase and catalyzes the final step in de novo synthesis and salvage pathway of NAD biosynthesis (Fig. 1), may increase the NAD+ level. Therefore the augmented pool size of NAD+(H) result in promotion of NADH (the carrier of electrons) level, leading to high generation of intracellular releasable electrons and better electricity performance of EAC.
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In addition, we also determined the effect of nadE on the electroproduction capacity of <i>S. oneidensis</i> MR-1 when co-expressed with nadD and nadM, and the results showed that the three co-expression could effectively increase the electroproduction efficiency of<i>S. oneidensis</i> MR-1
<figcaption>Fig.3 The out put voltage of S.oneidensis MR-1, S.oneidensis MR-1(ycel-pncB), S.oneidensis MR-1(nadD-nadE-nadM) when the anoditic solution is M9 buffer and 18mM lactate.</i>
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===Functional Parameters===
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The results showed that <i>S. oneidensis</i> MR-1(nadD-nadE-nadM) significantly higher discharge peak and prolonged high-efficiency discharge duration compared to the wild type. The highest out put voltage was up to 150.7 mV, with a 42.32% increase in the hightest power output . It is speculated that this could be attributed to the ability of<i>S. oneidensis</i> MR-1(nadD-nadE-nadM) to accelerate intracellular NADH synthesis, resulting in a higher power output.
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Latest revision as of 14:45, 12 October 2023
This part encodes NAD synthetase
Open reading frame of nadE
Intracellular redox state of electricity active cells (EAC) is one of the most important physiological traits of extracellular electron transfer efficiency. In particular, the NAD+(H) pool size plays a central role of most metabolic pathways. By overexpressing the NAD synthetase, encoded be gene nadE and catalyzes the final step in de novo synthesis and salvage pathway of NAD biosynthesis (Fig. 1), the NAD+ level is increased thereby up-regulating genes whose products catalyze NADH synthesis. Therefore the augmented pool size of NAD+(H) result in promotion of NADH(the carrier of electrons)level, leading to high generation of intracellular releasable electrons and better electricity performance of EAC. [1]
Fig. 1 De novo synthesis and salvage pathway of NAD biosynthesis.
HUST-China 2023
We codon optimized the sequence of nadE for S. oneidensis MR-1 and determined its effect on intracellular NAD(H/+) concentration when co-expressed with nadD[BBa_K4595014], nadM[BBa_K4595015], and the experimental results proved that it could effectively increase the intracellular NAD(H/+) concentration.
Fig.2 The NAD(H/+) concentration of S. oneidensis MR-1, S. oneidensis MR-1(ycel-pncB), S. oneidensis MR-1(nadE-nadD-nadM).
We Compared to the wild type, the total amount of NAD(H/+) in S. oneidensis MR-1(nadD-nadE-nadM) increased by 27.34%. This indicates that, S. oneidensis MR-1(nadD-nadE-nadM) facilitates more efficient electron transfer.
In addition, we also determined the effect of nadE on the electroproduction capacity of S. oneidensis MR-1 when co-expressed with nadD and nadM, and the results showed that the three co-expression could effectively increase the electroproduction efficiency ofS. oneidensis MR-1
Fig.3 The out put voltage of S.oneidensis MR-1, S.oneidensis MR-1(ycel-pncB), S.oneidensis MR-1(nadD-nadE-nadM) when the anoditic solution is M9 buffer and 18mM lactate.
The results showed that S. oneidensis MR-1(nadD-nadE-nadM) significantly higher discharge peak and prolonged high-efficiency discharge duration compared to the wild type. The highest out put voltage was up to 150.7 mV, with a 42.32% increase in the hightest power output . It is speculated that this could be attributed to the ability ofS. oneidensis MR-1(nadD-nadE-nadM) to accelerate intracellular NADH synthesis, resulting in a higher power output.
Fig. 1 De novo synthesis and salvage pathway of NAD biosynthesis.
