Generation of zero-valent sulfur from dissimilatory sulfate reduction in sulfate-reducing microorganisms

Abstract

Dissimilatory sulfate reduction (DSR) mediated by sulfate-reducing microorganisms (SRMs) plays a pivotal role in global sulfur, carbon, oxygen, and iron cycles since at least 3.5 billion y ago. The canonical DSR pathway is believed to be sulfate reduction to sulfide. Herein, we report a DSR pathway in phylogenetically diverse SRMs through which zero-valent sulfur (ZVS) is directly generated. We identified that approximately 9% of sulfate reduction was directed toward ZVS with S 8 as a predominant product, and the ratio of sulfate-to-ZVS could be changed with SRMs’ growth conditions, particularly the medium salinity. Further coculturing experiments and metadata analyses revealed that DSR-derived ZVS supported the growth of various ZVS-metabolizing microorganisms, highlighting this pathway as an essential component of the sulfur biogeochemical cycle.

Enhanced Biogenic Sulfidation of Zero-Valent Iron in Columns: Implications for Promoting Dechlorination in Permeable Reactive Barriers

“…S 2– oxidation via surface Fe­(III) is more likely, producing S 0 to form S n 2– . , This may also explain the smaller proportion of S n 2– downgradient (15–25 cm) of the Sand–Fe 0 –SRB column, because Fe­(III) was less abundant. A recent study suggests a third possibility that S 0 can be directly generated during dissimilatory sulfate reduction, and approximately 9% of SO 4 2– reduction was directed toward S 0 . Since SRB activity was most intensive in the upgradient zone where S n 2– was observed, the production of S 0 by microbial sulfate reduction cannot be excluded.…”

Procedures from samples to sulfur isotopic data: A review

“…Sulfur isotopic composition can be used to track different processes as a fingerprint in astronomy, 27–29 Earth life evolution, 30–34 stratigraphy, 35,36 mineral deposits, 37,38 environmental sciences, 39–42 ecology, 43–46 bromatology, 47,48 archaeological science, 49 medicine, 50 and forensic research 51–53 . In addition, 35 S can be used to trace sulfur behavior in forest systems, 54 the atmosphere, 55,56 and reductions 57 (see Section 8 of supporting information). In summary, sulfur isotopic studies are a powerful approach in various types of research. $$$$ \mathrm{MSR}:{\mathrm{S}\mathrm{O}}_{4\left(\mathrm{aq}\right)}^{2-}+2{\mathrm{CH}}_2{\mathrm{O}}_{\left(\mathrm{aq}\right)}\longrightarrow {\mathrm{H}}_2{\mathrm{S}}_{\left(\mathrm{g}\right)}+2{\mathrm{H}\mathrm{CO}}_{3\left(\mathrm{aq}\right)}^{-} $$$$ $$$$ {\mathrm{S}\mathrm{O}}_{4\left(\mathrm{aq}\right)}^{2-}+2{\mathrm{H}}_{2\left(\mathrm{aq}\right)}\longrightarrow {\mathrm{H}}_2{\mathrm{S}}_{\left(\mathrm{g}\right)}+{\mathrm{H}}_2{\mathrm{O}}_{\left(\mathrm{aq}\right)}.$$…”