Assessment of the stoichiometry and efficiency of CO2 fixation coupled to reduced sulfur oxidation
Klatt, Judith M.; Polerecky, Lubos
(2015) Frontiers in Microbiology, volume 6
(Article)
Abstract
Chemolithoautotrophic sulfur oxidizing bacteria (SOB) couple the oxidation of reduced sulfur compounds to the production of biomass. Their role in the cycling of carbon, sulfur, oxygen, and nitrogen is, however, difficult to quantify due to the complexity of sulfur oxidation pathways. We describe a generic theoretical framework for linking the
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stoichiometry and energy conservation efficiency of autotrophic sulfur oxidation while accounting for the partitioning of the reduced sulfur pool between the energy generating and energy conserving steps as well as between the main possible products (sulfate vs. zero-valent sulfur). Using this framework, we show that the energy conservation efficiency varies widely among SOB with no apparent relationship to their phylogeny. Aerobic SOB equipped with reverse dissimilatory sulfite reductase tend to have higher efficiency than those relying on the complete Sox pathway, whereas for anaerobic SOB the presence of membrane-bound, as opposed to periplasmic, nitrate reductase systems appears to be linked to higher efficiency. We employ the framework to also show how limited rate measurements can be used to estimate the primary productivity of SOB without the knowledge of the sulfate-to-zero-valent-sulfur production ratio. Finally, we discuss how the framework can help researchers gain new insights into the activity of SOB and their niches.
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Keywords: Carbon cycle, Chemolithoautotrophy, Energy conservation efficiency, Stoichiometry, Sulfur cycle, Sulfur oxidation pathways, adenosine diphosphate, adenosine triphosphate, ferredoxin, flavine adenine nucleotide, glyceraldehyde 3 phosphate, nicotinamide adenine dinucleotide, reduced nicotinamide adenine dinucleotide, sulfur, activity coefficient, article, carbon dioxide fixation, chemical reaction kinetics, chemolithoautotroph, citric acid cycle, conceptual framework, electron transport, energy conservation, factorial analysis, gibbs free energy, microbiological parameters, nonhuman, oxidation, sensitivity analysis, stoichiometry, sulfide oxidation, sulfur oxidizing bacterium, temperature, thermodynamics
ISSN: 1664-302X
Publisher: Frontiers Media S.A.
(Peer reviewed)
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