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Updated: May 29, 2026
15:19
Development of Sulfidogenic Sludge from Marine Sediments and Trichloroethylene Reduction in an Upflow Anaerobic Sludge Blanket Reactor
Published on: October 15, 2015
Revisiting the dissimilatory sulfate reduction pathway.
A S Bradley1, W D Leavitt, D T Johnston
1Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA. bradley@fas.harvard.edu
Geobiology
|September 3, 2011
Summary
This study revises the biochemical network for dissimilatory sulfate reduction, revealing new insights into sulfur isotope fractionation. Understanding this complex process is key for interpreting geological sulfur isotope records.
Area of Science:
- Geochemistry
- Biochemistry
- Microbiology
Background:
- Sulfur isotopes in geological records are influenced by biological and diagenetic processes.
- Dissimilatory sulfate reduction is a key process controlling sulfur isotope fractionation.
- Existing models of sulfate reduction lack a complete understanding of its reaction network.
Purpose of the Study:
- To propose a revised network topology for sulfur flow during dissimilatory sulfate reduction.
- To integrate recent biochemical data and enzyme crystal structures into a new model.
- To better understand the relationship between sulfate-reducing bacteria physiology and sulfur isotope fractionation.
Main Methods:
- Utilized biochemical data.
- Incorporated recently solved crystal structures of key enzymes.
- Developed a revised reaction network model for sulfate reduction.
Main Results:
- The proposed network is highly branched, explaining previous observations.
- Identified two primary pathways for sulfide production: one with and one without thionate intermediates.
- Highlighted the ratio of electron supply to Dsr versus sulfite delivery as critical for isotope fractionation.
Conclusions:
- The revised network provides a more comprehensive framework for understanding dissimilatory sulfate reduction.
- This model offers a potential explanation for observed sulfur isotope fractionation patterns.
- The findings can aid geochemists in interpreting the geological sulfur isotope record.
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