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Analysis and comparison of the microbial community structures of two enrichment cultures capable of reductively dechlorinating TCE and cis-DCE.
- Source :
-
Environmental microbiology [Environ Microbiol] 2004 Jan; Vol. 6 (1), pp. 45-54. - Publication Year :
- 2004
-
Abstract
- In order to study the effect of different chloroethenes (electron acceptors) on the bacterial composition of dechlorinating communities, two reductive dechlorinating enrichment cultures were developed that were able to reduce trichloroethene (TCE) and cis-1,2-dichloroethene (cis-DCE) to ethene using hydrogen as electron donor, respectively. The inoculum for the cultures was material from a methanogenic fluidized bed reactor (FBR), which was originally seeded with digester sludge and showed a stable capacity for tetrachloroethene (PCE) reduction to ethene for over six years. Molecular methods were used to determine and compare the microbial communities of these two enrichment cultures. A clone library of bacterial 16S rRNA genes was generated for each enrichment. The clones were screened into different groups by restriction fragment length polymorphism (RFLP) analysis using two different four base pair recognition restriction enzymes. A total of 12 sequence types were identified by phylogenetic analysis of nearly complete 16S rDNA sequences ( approximately 1450 bp). The sequences were affiliated with six recognized phyla of the domain Bacteria: Firmicutes (low G+C Gram-positives), Chloroflexi (green non-sulphur bacteria), Actinobacteria (high G+C Gram-positives), Bacteroidetes (Cytophaga-Flexibacter-Bacteroides), Nitrospira and Spirochaetes. The results led to the identification of an organism closely related to Dehalococcoides ethenogenes to be the presumptive dechlorinator in both enrichments. Different electron acceptors affected the bacterial diversity and the community profiles of the two enrichments. Most of the sequences identified in our dechlorinating enrichments shared high similarities with sequences previously obtained from other enriched dechlorinating cultures and chlorinated-compound-contaminated sediments or aquifers, suggesting these bacteria may have direct or indirect roles in reductive dechlorination.
- Subjects :
- Anaerobiosis
Biodegradation, Environmental
DNA Fingerprinting
DNA, Bacterial chemistry
DNA, Bacterial isolation & purification
DNA, Ribosomal chemistry
Ecosystem
Molecular Sequence Data
Oxidation-Reduction
Phylogeny
Polymorphism, Restriction Fragment Length
RNA, Ribosomal, 16S genetics
Sequence Analysis, DNA
Sewage microbiology
Bacteria classification
Bacteria metabolism
Chloroflexi classification
Chloroflexi metabolism
Dichloroethylenes metabolism
Tetrachloroethylene metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 1462-2912
- Volume :
- 6
- Issue :
- 1
- Database :
- MEDLINE
- Journal :
- Environmental microbiology
- Publication Type :
- Academic Journal
- Accession number :
- 14686940
- Full Text :
- https://doi.org/10.1046/j.1462-2920.2003.00525.x