Glycine Cleavage Powers Photoheterotrophic Growth of Chloroflexus aurantiacus in the Absence of H2

He, Lian; Wang, Yaya; You, Le; Khin, Yadana; Tang, Joseph Kuo-Hsiang; Tang, Yinjie J.

doi:10.3389/fmicb.2015.01467

Cited by 6 publications

(6 citation statements)

References 21 publications

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“…As a branch of glycolysis pathway, C1 metabolic module was responsible for the production of serine and glycine, ,, in which NADH and formate were synthesized as the intracellular electron carriers. , To increase the NADH regeneration, we overexpressed the relevant genes encoding NAD + -depended enzymes in S. oneidensis , namely, serA , serB , serC , gylA and gcvT , respectively, which could convert NAD + to NADH (Figure B, left column). However, no significant increase in NADH pool was observed upon the individual overexpression of these genes under anaerobic conditions in the absence of voltage discharge (Figure B, right column).…”

Section: Results and Discussionmentioning

confidence: 99%

“…Optimization of the C1 Metabolic Module. As a branch of glycolysis pathway, C1 metabolic module was responsible for the production of serine and glycine, 63,69,70 in which NADH and formate were synthesized as the intracellular electron carriers. 61,71 To increase the NADH regeneration, we overexpressed the relevant genes encoding NAD + -depended enzymes in S. oneidensis, namely, serA, serB, serC, gylA and gcvT, respectively, which could convert NAD + to NADH (Figure 2B, left column).…”

Section: ■ Results and Discussionmentioning

confidence: 99%

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Modular Engineering Intracellular NADH Regeneration Boosts Extracellular Electron Transfer of Shewanella oneidensis MR-1

Sun

et al. 2018

ACS Synth. Biol.

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Efficient extracellular electron transfer (EET) of exoelectrogens is essentially for practical applications of versatile bioelectrochemical systems. Intracellular electrons flow from NADH to extracellular electron acceptors via EET pathways. However, it was yet established how the manipulation of intracellular NADH impacted the EET efficiency. Strengthening NADH regeneration from NAD, as a feasible approach for cofactor engineering, has been used in regulating the intracellular NADH pool and the redox state (NADH/NAD ratio) of cells. Herein, we first adopted a modular metabolic engineering strategy to engineer and drive the metabolic flux toward the enhancement of intracellular NADH regeneration. We systematically studied 16 genes related to the NAD-dependent oxidation reactions for strengthening NADH regeneration in the four metabolic modules of S. oneidensis MR-1, i.e., glycolysis, C1 metabolism, pyruvate fermentation, and tricarboxylic acid cycle. Among them, three endogenous genes mostly responsible for increasing NADH regeneration were identified, namely gapA2 encoding a NAD-dependent glyceraldehyde-3-phosphate dehydrogenase in the glycolysis module, mdh encoding a NAD-dependent malate dehydrogenase in the TCA cycle, and pflB encoding a pyruvate-formate lyase that converted pyruvate to formate in the pyruvate fermentation module. An exogenous gene fdh* from Candida boidinii encoding a NAD-dependent formate dehydrogenase to increase NADH regeneration in the pyruvate fermentation module was further identified. Upon assembling these four genes in S. oneidensis MR-1, ∼4.3-fold increase in NADH/NAD ratio, and ∼1.2-fold increase in intracellular NADH pool were obtained under anaerobic conditions without discharge, which elicited ∼3.0-fold increase in the maximum power output in microbial fuel cells, from 26.2 ± 2.8 (wild-type) to 105.8 ± 4.1 mW/m (recombinant S. oneidensis), suggesting a boost in the EET efficiency. This modular engineering method in controlling the intracellular reducing equivalents would be a general approach in tuning the EET efficiency of exoelectrogens.

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Section: Results and Discussionmentioning

confidence: 99%

Section: ■ Results and Discussionmentioning

confidence: 99%

Modular Engineering Intracellular NADH Regeneration Boosts Extracellular Electron Transfer of Shewanella oneidensis MR-1

Sun

et al. 2018

ACS Synth. Biol.

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“…By contrast, overexpression of gapA had no effect on the production of acetoin, which may be due to the fact that glyceraldehyde 3-phosphate dehydrogenase is coencoded by gapA (SO_0538 and SO_2345) and gapB (SO_2347). Although their amino acid sequences were very similar, overexpression of SO_2345 alone could not effectively improve the catalytic activity of glyceraldehyde 3-phosphate dehydrogenase. , …”

Section: Resultsmentioning

confidence: 95%

Coproduction of Bioelectricity and Acetoin by Unbalanced Fermentation of Glycerol in Shewanella oneidensis Based on a Genome-Scale Metabolic Network

Kong

Zhao

Luo

et al. 2023

ACS Sustainable Chem. Eng.

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Unbalanced fermentation is a promising innovative strategy for biotechnological production processes. Guided by the genome-scale metabolic network iLJ1162, the central carbon metabolism was rewired to enhance the synthesis of (3R)-acetoin and link it to establish efficient extracellular electron transfer through unbalanced fermentation in Shewanella oneidensis. We first successfully constructed an engineered strain using glycerol as the sole carbon source to coproduce (3R)-acetoin and bioelectricity. Key engineering targets for (3R)-acetoin synthesis and bioelectricity were predicted by iLJ1162, including the glycolysis module (gapA and pgk), the serine bypass module (glyA, serA, serB, and serC), and the pyruvate fermentation module (fdh). As a result, we discovered that the serB gene was conducive to the production of bioelectricity (35.91 ± 1.04 mW m −2 ), and serC promoted the synthesis of (3R)-acetoin (213.5 ± 6.07 mg L −1 ) in the serine bypass module. However, the low power output capacity became the bottleneck, limiting the acetoin yield. To further balance the reducing force, we developed functional electrodes composed of carbon nanotubes and graphene oxide, as well as electron shuttles for improving electricity generation. The power density and the titer of (3R)-acetoin, respectively, reached up to 149.72 ± 2.72 mW m −2 and 313.61 ± 5.48 mg L −1 , which were 5.08 and 1.00 times higher than in the control. The optical purity of the resulting (3R)acetoin surpassed 90%. This study provides a new paradigm for achieving the "balance" between high value-added products with low reducibility and electricity production in unbalanced fermentation while boosting the titer of products based on model guidance.

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“…In specific, Chloroflexus aurantiacus is a Gram-negative organism possessing exceptional characteristics, such as anoxygenic, filamentous, thermophilic, phototrophic, and gliding properties [1][2][3]. Keeping out other phototrophic anoxygenic, Chloroflexus aurantiacus sprout effectively in environments with a moderate temperature of 50-60°C [4,5]. They can mostly acclimatize in various environmental circumstances, including wetlands, river water, hot springs, and sediments containing elevated-sulfide conditions [6,7].…”

Section: Introductionmentioning

confidence: 99%

Structural and Functional Elucidation of IF-3 Protein of Chloroflexus aurantiacus Involved in Protein Biosynthesis: An In Silico Approach

Saikat

Uddin

Ahmad

et al. 2021

BioMed Research International

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Chloroflexus aurantiacus is a thermophilic bacterium that produces a multitude of proteins within its genome. Bioinformatics strategies can facilitate comprehending this organism through functional and structural interpretation assessments. This study is aimed at allocating the structure and function through an in silico approach required for bacterial protein biosynthesis. This in silico viewpoint provides copious properties, including the physicochemical properties, subcellular location, three-dimensional structure, protein-protein interactions, and functional elucidation of the protein (WP_012256288.1). The STRING program is utilized for the explication of protein-protein interactions. The in silico investigation documented the protein’s hydrophilic nature with predominantly alpha (α) helices in its secondary structure. The tertiary-structure model of the protein has been shown to exhibit reasonably high consistency based on various quality assessment methods. The functional interpretation suggested that the protein can act as a translation initiation factor, a protein required for translation and protein biosynthesis. Protein-protein interactions also demonstrated high credence that the protein interconnected with 30S ribosomal subunit involved in protein synthesis. This study bioinformatically examined that the protein (WP_012256288.1) is affiliated in protein biosynthesis as a translation initiation factor IF-3 of C. aurantiacus.

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Glycine Cleavage Powers Photoheterotrophic Growth of Chloroflexus aurantiacus in the Absence of H2

Cited by 6 publications

References 21 publications

Modular Engineering Intracellular NADH Regeneration Boosts Extracellular Electron Transfer of Shewanella oneidensis MR-1

Modular Engineering Intracellular NADH Regeneration Boosts Extracellular Electron Transfer of Shewanella oneidensis MR-1

Coproduction of Bioelectricity and Acetoin by Unbalanced Fermentation of Glycerol in Shewanella oneidensis Based on a Genome-Scale Metabolic Network

Structural and Functional Elucidation of IF-3 Protein of Chloroflexus aurantiacus Involved in Protein Biosynthesis: An In Silico Approach

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