scholarly journals Harnessing Escherichia coli for bio-based production of formate under pressurized H2 and CO2 gases

2021 ◽  
Author(s):  
Magali Roger ◽  
Tom C. Reed ◽  
Frank Sargent

ABSRACTEscherichia coli is gram-negative bacterium that is a workhorse of the biotechnology industry. The organism has a flexible metabolism and can perform a mixed-acid fermentation under anaerobic conditions. Under these conditions E. coli synthesises a formate hydrogenlyase isoenzyme (FHL-1) that can generate molecular hydrogen and carbon dioxide from formic acid. The reverse reaction is hydrogen-dependent carbon dioxide reduction (HDCR), which has exciting possibilities in bio-based carbon capture and storage if it can be harnessed. In this study, an E. coli host strain was optimised for the production of formate from H2 and CO2 during bacterial growth in a pressurised batch bioreactor. A host strain was engineered that constitutively produced the FHL-1 enzyme and incorporation of tungsten in to the enzyme, in place of molybdenum, helped poise the reaction in the HDCR direction. The engineered E. coli strain showed an ability to grow under fermentative conditions while simultaneously producing formate from gaseous H2 and CO2 supplied in the bioreactor. However, while a sustained pressure of 10 bar N2 had no adverse effect on cell growth, when the culture was placed at or above 4 bar pressure of a H2:CO2 mixture then a clear growth deficiency was observed. Taken together, this work demonstrates that growing cells can be harnessed to hydrogenate carbon dioxide and provides fresh evidence that the FHL-1 enzyme may be intimately linked with bacterial energy metabolism.

Author(s):  
Magali Roger ◽  
Thomas C. P. Reed ◽  
Frank Sargent

Escherichia coli is gram-negative bacterium that is a workhorse for biotechnology. The organism naturally performs a mixed-acid fermentation under anaerobic conditions where it synthesises formate hydrogenlyase (FHL-1). The physiological role of the enzyme is the disproportionation of formate in to H 2 and CO 2 . However, the enzyme has been observed to catalyse hydrogenation of CO 2 given the correct conditions, and so has possibilities in bio-based carbon capture and storage if it can be harnessed as a hydrogen-dependent CO 2 -reductase (HDCR). In this study, an E. coli host strain was engineered for the continuous production of formic acid from H 2 and CO 2 during bacterial growth in a pressurised batch bioreactor. Incorporation of tungsten, in place of molybdenum, in FHL-1 helped to impose a degree of catalytic bias on the enzyme. This work demonstrates that it is possible to couple cell growth to simultaneous, unidirectional formate production from carbon dioxide and develops a process for growth under pressurised gases. IMPORTANCE Greenhouse gas emissions, including waste carbon dioxide, are contributing to global climate change. A basket of solutions is needed to steadily reduce emissions, and one approach is bio-based carbon capture and storage. Here we present out latest work on harnessing a novel biological solution for carbon capture. The Escherichia coli formate hydrogenlyase (FHL-1) was engineered to be constitutively expressed. Anaerobic growth under pressurised H 2 and CO 2 gases was established and aqueous formic acid was produced as a result. Incorporation of tungsten in to the enzyme in place of molybdenum proved useful in poising FHL-1 as a hydrogen-dependent CO 2 reductase (HDCR).


2008 ◽  
Vol 74 (24) ◽  
pp. 7561-7569 ◽  
Author(s):  
Vasiliy A. Portnoy ◽  
Markus J. Herrgård ◽  
Bernhard Ø. Palsson

ABSTRACT Fermentation of glucose to d-lactic acid under aerobic growth conditions by an evolved Escherichia coli mutant deficient in three terminal oxidases is reported in this work. Cytochrome oxidases (cydAB, cyoABCD, and cbdAB) were removed from the E. coli K12 MG1655 genome, resulting in the ECOM3 (E. coli cytochrome oxidase mutant) strain. Removal of cytochrome oxidases reduced the oxygen uptake rate of the knockout strain by nearly 85%. Moreover, the knockout strain was initially incapable of growing on M9 minimal medium. After the ECOM3 strain was subjected to adaptive evolution on glucose M9 medium for 60 days, a growth rate equivalent to that of anaerobic wild-type E. coli was achieved. Our findings demonstrate that three independently adaptively evolved ECOM3 populations acquired different phenotypes: one produced lactate as a sole fermentation product, while the other two strains exhibited a mixed-acid fermentation under oxic growth conditions with lactate remaining as the major product. The homofermenting strain showed a d-lactate yield of 0.8 g/g from glucose. Gene expression and in silico model-based analyses were employed to identify perturbed pathways and explain phenotypic behavior. Significant upregulation of ygiN and sodAB explains the remaining oxygen uptake that was observed in evolved ECOM3 strains. E. coli strains produced in this study showed the ability to produce lactate as a fermentation product from glucose and to undergo mixed-acid fermentation during aerobic growth.


2015 ◽  
Vol 2015 ◽  
pp. 1-5 ◽  
Author(s):  
Xiao-Xing Wei ◽  
Wei-Tao Zheng ◽  
Xue Hou ◽  
Jian Liang ◽  
Zheng-Jun Li

The alcohol dehydrogenase promoterPadhEand mixed acid fermentation pathway deficient mutants ofEscherichia coliwere employed to produce poly(3-hydroxybutyrate) (P3HB) under microaerobic condition. TheE. colimutant withackA-pta, poxB, ldhA, andadhEdeletions accumulated 0.67 g/L P3HB, up to 78.84% of cell dry weight in tube cultivation. The deletion of pyruvate formate-lyase genepflBdrastically decreased P3HB production and P3HB content to 0.09 g/L and 24.44%, respectively. OverexpressingpflBvia the plasmid in its knocked out mutant restored cell growth and P3HB accumulation, indicating the importance of the pyruvate formate-lyase in microaerobic carbon metabolism. The engineeredE. coliBWapld (pWYC09) produced 5.00 g/L P3HB from 16.50 g/L glucose in 24 h batch fermentation, and P3HB production yield from glucose was 0.30 g/g, which reached up to 63% of maximal theoretical yield.


2014 ◽  
Vol 60 (8) ◽  
pp. 547-556 ◽  
Author(s):  
Lijian Ding ◽  
Juanjuan Chen ◽  
Jianding Zou ◽  
Limin Zhang ◽  
Yangfang Ye

Previously, we reported the metabolic responses of Pseudomonas sp. strain HF-1, a nicotine-degrading bacterium, to nicotine stress. However, the metabolic effects of nicotine on non-nicotine-degrading bacteria that dominate the environment are still unclear. Here, we have used nuclear magnetic resonance based metabolomics in combination with multivariate data analysis methods to comprehensively analyze the metabolic changes in nicotine-treated Escherichia coli. Our results showed that nicotine caused the changes of energy-related metabolism that we believe are due to enhanced glycolysis and mixed acid fermentation as well as inhibited tricarboxylic acid cycle activity. Furthermore, nicotine resulted in the alteration of choline metabolism with a decreased synthesis of betaine but an increased production of dimethylamine. Moreover, nicotine caused a decrease in amino acid concentration and an alteration of nucleotide synthesis. We hypothesize that these changes caused the decrease in bacterial cell density observed in the experiment. These findings provide a comprehensive insight into the metabolic response of E. coli to nicotine stress. Our study highlights the value of metabolomics in elucidating the metabolic mechanisms of nicotine action.


2005 ◽  
Vol 33 (1) ◽  
pp. 42-46 ◽  
Author(s):  
R.G. Sawers

The production of dihydrogen by Escherichia coli and other members of the Enterobacteriaceae is one of the classic features of mixed-acid fermentation. Synthesis of the multicomponent, membrane-associated FHL (formate hydrogenlyase) enzyme complex, which disproportionates formate into CO2 and H2, has an absolute requirement for formate. Formate, therefore, represents a signature molecule in the fermenting E. coli cell and factors that determine formate metabolism control FHL synthesis and consequently dihydrogen evolution.


2022 ◽  
Author(s):  
George D Metcalfe ◽  
Frank Sargent ◽  
Michael Hippler

Escherichia coli (E. coli) is a facultative anaerobe that can grow in a variety of environmental conditions. In the complete absence of O2, E. coli can perform a mixed-acid fermentation that contains within it an elaborate metabolism of formic acid. In this study, we use cavity-enhanced Raman spectroscopy (CERS), FTIR, liquid Raman spectroscopy, isotopic labelling, and molecular genetics to make advances in the understanding of bacterial formate and H2 metabolism. It is shown that, under anaerobic conditions, formic acid is generated endogenously, excreted briefly from the cell, and then taken up again to be disproportionated to H2 and CO2 by formate hydrogenlyase (FHL-1). However, exogenously added D-labelled formate behaves quite differently from the endogenous formate and is taken up immediately, independently, and possibly by a different mechanism, by the cell and converted to H2 and CO2. Our data support an anion-proton symport model for formic acid transport. In addition, when E. coli was grown in a microaerobic environment it was possible to analyse aspects of formate and O2 respiration occurring alongside anaerobic metabolism. While cells growing under microaerobic conditions generated endogenous formic acid, no H2 was produced. However, addition of exogenous formate at the outset of cell growth did induce FHL-1 biosynthesis and resulted in formate-dependent H2 production in the presence of O2.


2020 ◽  
Vol 36 (2) ◽  
pp. 3-11
Author(s):  
O.A. Zhuravliova ◽  
Т.А. Voeikova ◽  
A.Yu. Gulevich ◽  
V.G. Debabov

The plasmidless and markerless Escherichia coli succinate producing strain SGM2.0Pyc-int has been engineered and characterized. The strain has the inactivated main mixed-acid fermentation pathways due to the deletions of ldhA,poxB, ackA,pta, and adhE genes, constitutively expresses the genes of the aceEF-lpdA operon encoding components of pyravate dehydrogenase complex, and possesses the chromosomally integrated Bacillus subtilis pycA gene coding for pyruvate carboxylase. The capacity of the strain to synthesize succinic acid in course of dual-phase aerobic-anaerobic fermentation with lignocellulosic sugars as substrates was studied. The SGM2.0Pyc-int strain synthesized succinic acid from glucose, xylose, and arabinose with a molar yields of 1.41 mol/mol, 1.18 mol/mol, and 1.18 mol/mol, respectively, during the anaerobic production stage. The constructed strain has great potential for developing efficient processes for the succinic acid production from plant biomass-derived sugars. Escherichia coli, fermentation, arabinose, glucose, xylose, succinic acid. The work was supported by a Grant from the Russian Foundation for Basic Research (Project no. 18-29-14005).


2021 ◽  
Vol 104 (2) ◽  
pp. 003685042110196
Author(s):  
Brendon Mpofu ◽  
Hembe E Mukaya ◽  
Diakanua B Nkazi

Carbon dioxide has been identified as one of the greenhouse gases responsible for global warming. Several carbon capture and storage technologies have been developed to mitigate the large quantities of carbon dioxide released into the atmosphere, but these are quite expensive and not easy to implement. Thus, this research analyses the technical and economic feasibility of using calcium leached from cow bone to capture and store carbon dioxide through the mineral carbonation process. The capturing process of carbon dioxide was successful using the proposed technique of leaching calcium from cow shinbone (the tibia) in the presence of HCl by reacting the calcium solution with gaseous carbon dioxide. AAS and XRF analysis were used to determine the concentration of calcium in leached solutions and the composition of calcium in cow bone respectively. The best leaching conditions were found to be 4 mole/L HCl and leaching time of 6 h. Under these conditions, a leaching efficiency of 91% and a calcium conversion of 83% in the carbonation reaction were obtained. Other factors such as carbonation time, agitation rate, and carbonation reaction temperature had little effect on the yield. A preliminary cost analysis showed that the cost to capture 1 ton of CO2 with the proposed technique is about US$ 268.32, which is in the acceptable range of the capturing process. However, the cost of material used and electricity should be reviewed to reduce the preliminary production cost.


2014 ◽  
Vol 68 (5) ◽  
Author(s):  
Nabilah Zaini ◽  
Khairul Sozana Nor Kamarudin

Emission of carbon dioxide (CO2) becomes a major concern in combating issues of global warming. The strategy to reduce the concentration of CO2 could be achieved by executing carbon capture and storage (CCS) technology such as adsorption. This study presents the used of kenaf as a green source for CO2 adsorption material. The modification of MEA on kenaf is a novelty work to enhance the capacity of adsorbent since MEA has been proved to have potential in separating CO2 in industrial applications. In this work, 10 wt % of MEA has been impregnated on kenaf via wet impregnation method. The adsorption of CO2 study was conducted by passing CO2/N2 mixture in a ratio of 30:70 in a Pressure Swing Adsorption (PSA) system with a pressure up to 1.5 bar at ambient temperature. Result obtained via SEM analysis shows that the morphology of kenaf was affected after modification with MEA. However, the presence of MEA on kenaf has improved the CO2 adsorption capacity by 16 %. In addition, the adsorption equilibrium data for kenaf and MEA modified kenaf are well fitted in Freundlich isotherm model at low pressure and well fitted in Langmuir model at higher pressure. This study indicates that the introduction of MEA on kenaf could enhance the CO2 adsorption process.  


2021 ◽  
Author(s):  
Alan Junji Yamaguchi ◽  
Kaito Kobayashi ◽  
Toru Sato ◽  
Takaomi Tobase

Abstract The global warming is an important environmental concern and the carbon capture and storage (CCS) emerges as a very promising technology. Captured carbon dioxide (CO2) can be stored onshore or offshore in the aquifers. There is, however, a risk that stored CO2 will leak due to natural disasters. One possible solution to this is the natural formation of CO2 hydrates. Gas hydrate has an ice-like structure in which small gas molecules are trapped within cages of water molecules. Hydrate formation occurs under high pressure and low temperature conditions. Its stability under these conditions acts like a cap rock to prevent CO2 leaks. The main objective of this study is to understand how hydrate formation affects the permeability of leaked CO2 flows. The phase field method was used to simulate microscopic hydrate growth within the pore space of sand grains, while the lattice Boltzmann method was used to simulate two-phase flow. The results showed that the hydrate morphology within the pore space changes with the flow, and the permeability is significantly reduced as compared with the case without the flow.


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