Field application of glycerol to enhance reductive dechlorination of chlorinated ethenes and its impact on microbial community
Language English Country Great Britain, England Media print-electronic
Document type Journal Article
PubMed
36181841
DOI
10.1016/j.chemosphere.2022.136640
PII: S0045-6535(22)03133-2
Knihovny.cz E-resources
- Keywords
- Bioremediation, Chlorinated ethenes, Enhanced reductive dechlorination, Glycerol, Organohalide-respiring bacteria,
- MeSH
- Bacteria genetics metabolism MeSH
- Biodegradation, Environmental MeSH
- Water Pollutants, Chemical * metabolism MeSH
- Chloroflexi * metabolism MeSH
- Glycerol metabolism MeSH
- Corrinoids * MeSH
- Microbiota * MeSH
- Oxidoreductases metabolism MeSH
- Soil MeSH
- Sulfates metabolism MeSH
- Tetrachloroethylene * metabolism MeSH
- Trichloroethylene * metabolism MeSH
- Carbon metabolism MeSH
- Vinyl Chloride * MeSH
- Publication type
- Journal Article MeSH
- Names of Substances
- Water Pollutants, Chemical * MeSH
- ethylene MeSH Browser
- Glycerol MeSH
- Corrinoids * MeSH
- Oxidoreductases MeSH
- Soil MeSH
- Sulfates MeSH
- Tetrachloroethylene * MeSH
- Trichloroethylene * MeSH
- Carbon MeSH
- Vinyl Chloride * MeSH
Chlorinated ethenes (CEs) are common and persistent contaminants of soil and groundwater. Their degradation is mostly driven by a process of bacterial reductive dechlorination (also called organohalide respiration) in anaerobic conditions. This study summarizes the outcomes of the long-term in-situ application of glycerol for the enhanced reductive dechlorination of CEs on a highly contaminated site. Glycerol injection resulted in an almost immediate increase in the abundance of fermentative Firmicutes, which produce essential sources of carbon (acetate) and electrons (H2) for organohalide-respiring bacteria (OHRB) and change groundwater conditions to be suitable for OHRB growth. The decreased redox potential of groundwater promoted also the proliferation of sulfate-reducing bacteria, which compete for electron donors with OHRB but at the same time support their growth by producing essential corrinoids and acetate. A considerable increase in the abundance of OHRB Dehalococcoides, concurrently with vinyl chloride (VC) reductase gene levels, was revealed by real time polymerase chain reaction (qPCR) method. Consistent with the shifts in bacterial populations, the concentrations of pollutants tetrachloroethylene and trichloroethylene decreased during the monitoring period, with rising levels of cis-1,2-dichloroethylene, VC, and most importantly, the final CE degradation products: ethene and ethane. Our study implies the importance of syntrophic bacterial interactions for successful and complete CE degradation and evaluates glycerol as convenient substrate to enhance reductive dechlorination and as an effective source of electrons for OHRB.
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