Balancing cellular redox metabolism in microbial electrosynthesis and electro fermentation – A chance for metabolic engineering

Kracke, Frauke; Lai, Bin; Yu, Shiqin; Krömer, Jens O.

doi:10.1016/j.ymben.2017.12.003

Cited by 87 publications

(64 citation statements)

References 160 publications

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“…In both the MESs, current generation under 0.8 V applied voltage confirms electron consumption on the cathode by microorganisms and possible biotransformation of CO 2 to the organic acids. [45] In addition, when the substrate was added to the reactors, the current generation increased rapidly and then decreased with the days of operation followed by the utilization of CO 2 by the microorganisms present on the cathodic biofilm. This is a typical current production profile of a biological fuel cells as reported in the earlier studies.…”

Section: Current Generation Profile Of Messmentioning

confidence: 99%

Highly Porous Fe_xMnO_y Microsphere as an Efficient Cathode Catalyst for Microbial Electrosynthesis of Volatile Fatty Acids from CO₂

Noori¹,

Min²

2019

ChemElectroChem

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Microbial electrosynthesis (MES) can efficiently convert CO2 into valuable chemicals. A biocathode, which plays central role in MES process, is expected to have very high surface area and catalytic activity to derive the cathodic reaction flawlessly. In this study, a highly porous bimetallic FexMnOy (x=1, 2 and y=3, 4) microsphere was synthesized and applied as cathode catalyst in a single chamber MES. MES having FexMnOy exhibited higher net acetate production rate (204 mM/m2d) and coulombic efficiency (58 %) than the MES without catalyst (180 mM/m2d and 34 %). The excellent performance of MES with FexMnOy was attributed to the high Brunauer‐Emmett‐Teller (BET) surface area (around 278 m2/g) with rough surface and efficient electron transfer from cathode to microorganism promoted by FexMnOy complex. The cathode with FexMnOy reduced charge transfer resistance by ∼70 % and enhanced the exchange current density by 7.2‐times compared to plain cathode. This study suggests that FexMnOy can be used as the highly efficient and low‐cost catalyst on cathode of scaled up MESs.

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Section: Current Generation Profile Of Messmentioning

confidence: 99%

Highly Porous Fe_xMnO_y Microsphere as an Efficient Cathode Catalyst for Microbial Electrosynthesis of Volatile Fatty Acids from CO₂

Noori¹,

Min²

2019

ChemElectroChem

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“…Despite these accomplishments, these strategies couple the redox state of the electrode to multiple intracellular redox biomolecules, resulting in off-target effects, cellular toxicity, and poor control of biosynthesis 1,3,4 . To achieve precise electrochemical control of a biological process, a strategy that couples an electrode to a specific intracellular redox pool is still needed 12,13 .…”

Section: Figurementioning

confidence: 99%

Precise electronic control of redox reactions insideEscherichia coliusing a genetic module

Baruch

Tejedor-Sanz²,

Su³

et al. 2020

Preprint

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18Microorganisms regulate the redox state of different biomolecules to precisely control 19 biological processes. These processes can be modulated by electrochemically coupling 20 intracellular biomolecules to an external electrode, but current approaches afford only 21 limited control and specificity. Here we describe specific electrochemical control of the 22 Microorganisms accomplish important biological functions such as conserving energy, 32 regulating gene expression, and powering biosynthesis using different redox-active 33 biomolecules. To enable control of these processes in any microorganism, researchers have 34 coupled the redox state of these biomolecules to an external electrode using membrane-35 permeable, small molecule redox mediators 1-5 , redox polymers 6 , and membrane-36 intercalated nanostructures 7,8 . These approaches can allow cells to produce electrical 37 current or consume it, resulting in either oxidation or reduction of intracellular redox species, 38 respectively. Bioelectrochemical devices can then be used to drive biosynthetic reactions 39 1,4,5 , perform bioelectronic sensing 9 , actuate gene expression 3 , and modulate cellular growth 40 10,11 within the microorganism of interest. Despite these accomplishments, these strategies 41 Results 75E. coli consume current using mtr and native oxidoreductases 76 We first sought to determine if the Mtr pathway could allow cathodic electrons to 77 directly enter a heterologous host upon addition of an electron acceptor. Since E. coli has 78 two MK-linked fumarate reductases, FrdABCD and SdhABCD, we hypothesized that the Mtr 79 pathway in E. coli could deliver cathodic electrons via these native proteins to fumarate 80 ( Figure 1A). To probe the specific role of the Mtr pathway, we compared the behavior of 81 several strains: E. coli expressing only the cytochrome c maturation (ccm) genes (abbrev. 82Ccm-E.coli) 17 , E. coli expressing ccm and mtrCAB (abbrev. Mtr-E. coli) 15 , and E. coli 83 expressing ccm and cymAmtrCAB (abbrev. CymAMtr-E. coli) 17 . The ccm genes are required 84 to make cytochromes c in the C43(DE3) parental background. 85To prepare E. coli for cathodic conditions, individual strains were first grown 86 aerobically, incubated in potentiostatic-controlled bioreactors under anaerobic, anodic 87 conditions (∆V=+200 mV Ag/AgCl ) for at least one day. Under these conditions, the CymAMtr-88 E. coli strain produced a significant steady-state current, while Ccm-E. coli and Mtr-E. coli 89 produced much lower currents (Figure 2A), reinforcing that CymA is important for current 90 production [16][17][18] . As anaerobic conditions were maintained, the electrode bias was then 91 switched to cathodic conditions (∆V= -560 V Ag/AgCl ), fumarate was added, and current 92 consumption was measured. In the absence of E. coli, neither current consumption nor 93 fumarate reduction was observed (Figure S1A). Likewise, the Ccm-E. coli strain did not 94 consume significant levels of current (Figure 2B). In contrast, both the Mtr-E. coli and t...

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“…Metabolic engineering of EAB, e.g., S. oneidensis MR-1, has been examined mainly for the purpose of producing valued chemicals in MES with the aid of electric energy (Kracke et al 2018). On the other hand, since electricity generation in MFCs has mostly been attempted in association with the treatment of organic wastes, naturally occurring microbiomes rather than pure cultures of EAB have been exploited in MFCs.…”

Section: Metabolic Engineering In Combination With Electrochemistrymentioning

confidence: 99%

Understanding and engineering electrochemically active bacteria for sustainable biotechnology

Hirose

Kasai

Koga

et al. 2019

Bioresour. Bioprocess.

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Electrochemically active bacteria (EAB) receive considerable attention in sustainable biotechnology, since they are essential components in microbial fuel cells (MFCs) that are able to generate electricity from biomass wastes. EAB are also expected to be applied to the production of valued chemicals in microbial electrosynthesis systems (MESs) with the supply of electric energy from electrodes. It is, therefore, important to deepen our understanding of EAB in terms of their physiology, genetics and genomics. Knowledge obtained in these studies will facilitate the engineering of EAB for developing more efficient biotechnology processes. In this article, we summarize current knowledge on Shewanella oneidensis MR-1, a representative EAB extensively studied in the laboratory. Studies have shown that catabolic activities of S. oneidensis MR-1 are well tuned for efficiently conserving energy under varied growth conditions, e.g., different electrode potentials, which would, however, in some cases, hamper its application to biotechnology processes. We suggest that understanding of molecular mechanisms underlying environmental sensing and catabolic regulation in EAB facilitates their biotechnological applications.

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Balancing cellular redox metabolism in microbial electrosynthesis and electro fermentation – A chance for metabolic engineering

Cited by 87 publications

References 160 publications

Highly Porous Fe_xMnO_y Microsphere as an Efficient Cathode Catalyst for Microbial Electrosynthesis of Volatile Fatty Acids from CO₂

Highly Porous Fe_xMnO_y Microsphere as an Efficient Cathode Catalyst for Microbial Electrosynthesis of Volatile Fatty Acids from CO₂

Precise electronic control of redox reactions insideEscherichia coliusing a genetic module

Understanding and engineering electrochemically active bacteria for sustainable biotechnology

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Balancing cellular redox metabolism in microbial electrosynthesis and electro fermentation – A chance for metabolic engineering

Cited by 87 publications

References 160 publications

Highly Porous FexMnOy Microsphere as an Efficient Cathode Catalyst for Microbial Electrosynthesis of Volatile Fatty Acids from CO2

Highly Porous FexMnOy Microsphere as an Efficient Cathode Catalyst for Microbial Electrosynthesis of Volatile Fatty Acids from CO2

Precise electronic control of redox reactions insideEscherichia coliusing a genetic module

Understanding and engineering electrochemically active bacteria for sustainable biotechnology

Contact Info

Product

Resources

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Highly Porous Fe_xMnO_y Microsphere as an Efficient Cathode Catalyst for Microbial Electrosynthesis of Volatile Fatty Acids from CO₂

Highly Porous Fe_xMnO_y Microsphere as an Efficient Cathode Catalyst for Microbial Electrosynthesis of Volatile Fatty Acids from CO₂