Thiosulfate disproportionation by Desulfotomaculum thermobenzoicum

Area of Science:

• Microbiology
• Environmental Science
• Biochemistry

Background:

• Sulfate-reducing bacteria play crucial roles in biogeochemical cycles.
• Thiosulfate disproportionation is an energy-conserving process for some microorganisms.
• Understanding microbial metabolism is key to predicting environmental impacts.

Purpose of the Study:

• To investigate the ability of Desulfotomaculum species to grow via thiosulfate disproportionation.
• To determine the effect of acetate on thiosulfate disproportionation by Desulfotomaculum thermobenzoicum.

Main Methods:

• Cultivation of Desulfotomaculum species under anaerobic conditions.
• Growth experiments with thiosulfate as the sole electron donor.
• Analysis of sulfate and sulfide production to confirm thiosulfate disproportionation.
• Addition of acetate to assess its impact on growth and metabolism.

Main Results:

• Desulfotomaculum thermobenzoicum demonstrated growth through thiosulfate disproportionation, yielding stoichiometric sulfate and sulfide.
• Other tested Desulfotomaculum species (D. nigrificans, D. ruminis) and Desulfosporosinus orientis did not exhibit growth via this pathway.
• Sulfite was not disproportionated by the studied microorganisms.
• The presence of acetate significantly enhanced both growth and thiosulfate disproportionation by D. thermobenzoicum.

Conclusions:

• Desulfotomaculum thermobenzoicum is capable of thiosulfate disproportionation for energy and growth.
• Acetate acts as a growth promoter and enhances thiosulfate disproportionation in D. thermobenzoicum.
• This metabolic capability is specific to D. thermobenzoicum among the tested species, highlighting metabolic diversity within the Desulfotomaculum genus.