Electron carriers in microbial sulfate reduction inferred from experimental and environmental sulfur isotope fractionations.

ABSTRACT: Dissimilatory sulfate reduction (DSR) has been a key process influencing the global carbon cycle, atmospheric composition and climate for much of Earth's history, yet the energy metabolism of sulfate-reducing microbes remains poorly understood. Many organisms, particularly sulfate reducers, live in low-energy environments and metabolize at very low rates, requiring specific physiological adaptations. We identify one such potential adaptation-the electron carriers selected for survival under energy-limited conditions. Employing a quantitative biochemical-isotopic model, we find that the large S isotope fractionations (>55‰) observed in a wide range of natural environments and culture experiments at low respiration rates are only possible when the standard-state Gibbs free energy (ΔG'°) of a

SUBMITTER: Wenk CB 

PROVIDER: S-EPMC5776465 | biostudies-literature | 2018 Feb

REPOSITORIES: biostudies-literature