Energy generation from the CO oxidation-hydrogen production pathway in Rubrivivax gelatinosus.
When incubated in the presence of CO gas, Rubrivivax gelatinosus CBS induces a CO oxidation-H2 production pathway according to the stoichiometry CO + H2O --> CO2 + H2. Once induced, this pathway proceeds equally well in both light and darkness. When light is not present, CO can serve as the sole carbon source, supporting cell growth anaerobically with a cell doubling time of nearly 2 days. This observation suggests that the CO oxidation reaction yields energy. Indeed, new ATP synthesis was detected in darkness following CO additions to the gas phase of the culture, in contrast to the case for a control that received an inert gas such as argon. When the CO-to-H2 activity was determined in the presence of the electron transport uncoupler carbonyl-cyanide m-chlorophenylhydrazone (CCCP), the rate of H2 production from CO oxidation was enhanced nearly 40% compared to that of the control. Upon the addition of the ATP synthase inhibitor N,N'-dicyclohexylcarbodiimide (DCCD), we observed an inhibition of H2 production from CO oxidation which could be reversed upon the addition of CCCP. Collectively, these data strongly suggest that the CO-to-H2 reaction yields ATP driven by a transmembrane proton gradient, but the detailed mechanism of this reaction is not yet known. These findings encourage additional research aimed at long-term H2 production from gas streams containing CO.
Maness
Pin-Ching
PC
National Renewable Energy Laboratory, 1617 Cole Blvd., Golden, Colorado 80401-3393, USA. pinching_maness@nrel.gov
Huang
Jie
J
Smolinski
Sharon
S
Tek
Vekalet
V
Vanzin
Gary
G
D000255:Adenosine Triphosphate / Q000378:metabolism*; D000693:Anaerobiosis; D020562:Betaproteobacteria / Q000254:growth & development / Q000378:metabolism*; D002245:Carbon Dioxide / Q000378:metabolism; D002248:Carbon Monoxide / Q000378:metabolism*; D003470:Culture Media; D003624:Darkness; D004734:Energy Metabolism; D006859:Hydrogen / Q000378:metabolism*; D008027:Light; D010084:Oxidation-Reduction
D003470:Culture Media; D002245:Carbon Dioxide; D002248:Carbon Monoxide; D006859:Hydrogen; D000255:Adenosine Triphosphate