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Reductive desulfurization of dibenzyldisulfide.
1Biological Sciences Department, Illinois State University, Normal, Illinois 61761.
Applied and Environmental Microbiology
|July 1, 1992
Summary
Dibenzyldisulfide degradation by sewage microbes produces toluene, with benzyl mercaptan as an intermediate. Methanogenesis inhibition did not affect toluene yields, indicating biological activity is key.
Area of Science:
- Environmental microbiology
- Biogeochemical cycling
Background:
- Dibenzyldisulfide (DBDS) is a sulfur compound found in environments.
- Understanding microbial degradation pathways is crucial for environmental remediation.
Purpose of the Study:
- To investigate the reductive degradation of dibenzyldisulfide by a methanogenic mixed culture.
- To identify the products and intermediates of DBDS degradation.
- To elucidate the role of microbial activity versus chemical reduction in the process.
Main Methods:
- Cultivation of a methanogenic mixed culture from sewage digestor sludge.
- Incubation of DBDS under anaerobic conditions with the microbial culture.
- Analysis of degradation products using gas chromatography and mass spectrometry.
- Experimental manipulation of methanogenesis using 2-bromoethane sulfonic acid and chemical reducing agents like Ti(III).
Main Results:
- Toluene was identified as a major product of DBDS reductive degradation.
- Benzyl mercaptan was observed as a transient intermediate.
- Toluene production was dependent on biological activity.
- The chemical reducing agent Ti(III) contributed to benzyl mercaptan formation.
- Methanogenesis was not required for toluene production, as evidenced by experiments with 2-bromoethane sulfonic acid.
Conclusions:
- Methanogenic consortia can reductively degrade dibenzyldisulfide to toluene.
- Benzyl mercaptan is a key intermediate in this pathway.
- Both microbial and chemical reduction processes contribute to intermediate formation.
- DBDS degradation to toluene can occur independently of methanogenesis.