scholarly journals Elementary Flux Mode Analysis of Acetyl-CoA Pathway in Carboxydothermus hydrogenoformans Z-2901

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Rajadurai Chinnasamy Perumal ◽  
Ashok Selvaraj ◽  
Gopal Ramesh Kumar
Keyword(s):  
Carbon Monoxide ◽  
Hydrogen Production ◽  
Gene Knockout ◽  
Mode Analysis ◽  
Hydrogen Yield ◽  
Acetyl Coa ◽  
Elementary Flux Mode ◽  
Acetyl Coa Pathway ◽  
Carboxydothermus Hydrogenoformans ◽  
Flux Mode

Carboxydothermus hydrogenoformans is a carboxydotrophic hydrogenogenic bacterium species that produces hydrogen molecule by utilizing carbon monoxide (CO) or pyruvate as a carbon source. To investigate the underlying biochemical mechanism of hydrogen production, an elementary mode analysis of acetyl-CoA pathway was performed to determine the intermediate fluxes by combining linear programming (LP) method available in CellNetAnalyzer software. We hypothesized that addition of enzymes necessary for carbon monoxide fixation and pyruvate dissimilation would enhance the theoretical yield of hydrogen. An in silico gene knockout of pyk, pykC, and mdh genes of modeled acetyl-CoA pathway allows the maximum theoretical hydrogen yield of 47.62 mmol/gCDW/h for 1 mole of carbon monoxide (CO) uptake. The obtained hydrogen yield is comparatively two times greater than the previous experimental data. Therefore, it could be concluded that this elementary flux mode analysis is a crucial way to achieve efficient hydrogen production through acetyl-CoA pathway and act as a model for strain improvement.

scholarly journals Metabolomics integrated elementary flux mode analysis in large metabolic networks

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Matthias P. Gerstl ◽  
David E. Ruckerbauer ◽  
Diethard Mattanovich ◽  
Christian Jungreuthmayer ◽  
Jürgen Zanghellini
Keyword(s):  
Metabolic Networks ◽  
Mode Analysis ◽  
Elementary Flux Mode ◽  
Flux Mode

Thermodynamic Analysis of Hydrogen Production from Ethanol in Supercritical Water Oxidation

2011 ◽  
Vol 110-116 ◽  
pp. 77-82
Author(s):  
Nawadee Srisiriwat
Keyword(s):  
Carbon Dioxide ◽  
Carbon Monoxide ◽  
Hydrogen Production ◽  
Thermodynamic Analysis ◽  
Supercritical Water ◽  
Water Oxidation ◽  
Equilibrium Composition ◽  
Operating Conditions ◽  
Molar Ratio ◽  
Hydrogen Yield

A thermodynamic analysis was performed for hydrogen production from ethanol reforming and oxidation in supercritical water (SCW) conditions. The minimization of Gibbs free energy was used to calculate the equilibrium composition to investigate the effect of operating conditions, pressure, temperature, H2O2:EtOH molar ratio and H2O:EtOH molar ratio, on product yields. The theoretical results indicated that the yields of hydrogen and carbon monoxide decreased as the pressure increased but a H2/CO ratio at atmospheric pressure was lower than that at SCW conditions. High temperatures increased the efficiency of hydrogen production although the amount of carbon monoxide also increased. The presence of oxygen led to great decreases in methane oxidized to carbon dioxide and water. The spending of some hydrogen oxidized to water resulting in a lower hydrogen yield. High H2O:EtOH ratios increased the yields of hydrogen and carbon dioxide but decreased the methane and carbon monoxide production. It is possible to conclude that high temperature, high H2O:EtOH ratio and low addition of oxygen should lead to best results in the SCWO of ethanol.

Autothermal Reforming of Ethanol for Hydrogen Production: Thermodynamic Analysis

2013 ◽  
Vol 415 ◽  
pp. 658-665 ◽  
Author(s):  
Nawadee Srisiriwat ◽  
Chananchai Wutthithanyawat
Keyword(s):  
Carbon Monoxide ◽  
Hydrogen Production ◽  
Thermodynamic Analysis ◽  
Equilibrium Composition ◽  
Product Distribution ◽  
Autothermal Reforming ◽  
Hydrogen Yield ◽  
Molar Ratios ◽  
Carbon Monoxide Formation ◽  
Gibbs Free Energy Minimization

This work presents the autothermal reforming (ATR), or called oxidative steam reforming (OSR), of ethanol for hydrogen production. A thermodynamic analysis of product distribution for ATR from ethanol has been performed by using the method of Gibbs free energy minimization. The effect of steam-to-carbon (S:C) and air-to-carbon (A:C) molar ratios under adiabatic temperature of ATR reactor on chemical equilibrium composition of hydrogen rich stream is investigated. An increase of S:C ratio increases an efficiency of hydrogen production while carbon monoxide formation decreases but, however, more energy consumption for preheating reactants is also needed. An increase of A:C ratio in the range between 0 and 1.75 causes an increase of hydrogen yield but at greater A:C ratio, a decrease of hydrogen production and more water formation can be found. The results of the thermodynamic equilibrium show that the predicted hydrogen composition in the reaction of fuel-water-air system at constant temperature is higher than that obtained from experiment in both the absence and presence of catalysts in the OSR reaction when the temperature is fixed at 700 °C. The predicted carbon monoxide is lower than that obtained from the results of non-catalytic reaction but higher than that attained from the presence of catalyst in process.

scholarly journals Deconstructing Methanosarcina acetivorans into an acetogenic archaeon

2022 ◽  
Vol 119 (2) ◽  
pp. e2113853119
Author(s):  
Christian Schöne ◽  
Anja Poehlein ◽  
Nico Jehmlich ◽  
Norman Adlung ◽  
Rolf Daniel ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Energy Conservation ◽  
Carbon Fixation ◽  
Coenzyme A ◽  
Methanogenic Archaea ◽  
Methanosarcina Acetivorans ◽  
Acetyl Coa ◽  
Acetyl Coenzyme A ◽  
Acetyl Coenzyme ◽  
Acetyl Coa Pathway

The reductive acetyl-coenzyme A (acetyl-CoA) pathway, whereby carbon dioxide is sequentially reduced to acetyl-CoA via coenzyme-bound C1 intermediates, is the only autotrophic pathway that can at the same time be the means for energy conservation. A conceptually similar metabolism and a key process in the global carbon cycle is methanogenesis, the biogenic formation of methane. All known methanogenic archaea depend on methanogenesis to sustain growth and use the reductive acetyl-CoA pathway for autotrophic carbon fixation. Here, we converted a methanogen into an acetogen and show that Methanosarcina acetivorans can dispense with methanogenesis for energy conservation completely. By targeted disruption of the methanogenic pathway, followed by adaptive evolution, a strain was created that sustained growth via carbon monoxide–dependent acetogenesis. A minute flux (less than 0.2% of the carbon monoxide consumed) through the methane-liberating reaction remained essential, indicating that currently living methanogens utilize metabolites of this reaction also for anabolic purposes. These results suggest that the metabolic flexibility of methanogenic archaea might be much greater than currently known. Also, our ability to deconstruct a methanogen into an acetogen by merely removing cellular functions provides experimental support for the notion that methanogenesis could have evolved from the reductive acetyl-coenzyme A pathway.

Predicting genetic engineering targets with Elementary Flux Mode Analysis: a review of four current methods

2015 ◽  
Vol 32 (6) ◽  
pp. 534-546 ◽  
Author(s):  
David E. Ruckerbauer ◽  
Christian Jungreuthmayer ◽  
Jürgen Zanghellini
Keyword(s):  
Genetic Engineering ◽  
Mode Analysis ◽  
Elementary Flux Mode ◽  
Flux Mode
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