[Characterization of Reductive Dechlorination of Chlorinated Ethylenes by Anaerobic Consortium].
Huan Jing Ke Xue
; 45(2): 1080-1089, 2024 Feb 08.
Article
em Zh
| MEDLINE
| ID: mdl-38471945
ABSTRACT
Tetrachloroethylene ï¼PCEï¼ and trichloroethylene ï¼TCEï¼ are typical volatile halogenated organic compounds in groundwater that pose serious threats to the ecological environment and human health. To obtain an anaerobic microbial consortium capable of efficiently dechlorinating PCE and TCE to a non-toxic end product and to explore its potential in treating contaminated groundwaterï¼ an anaerobic microbial consortium W-1 that completely dechlorinated PCE and TCE to ethylene was obtained by repeatedly feeding PCE or TCE into the contaminated groundwater collected from an industrial site. The dechlorination rates of PCE and TCE were ï¼120.1 ±4.9ï¼ µmol·ï¼L·dï¼-1 and ï¼172.4 ±21.8ï¼ µmol·ï¼L·dï¼-1 in W-1ï¼ respectively. 16S rRNA gene amplicon sequencing and quantitative PCR ï¼qPCRï¼ showed that the relative abundance of Dehalobacter increased from 1.9% to 57.1%ï¼ with the gene copy number increasing by 1.7×107 copies per 1 µmol Cl- released when 98.3 µmol of PCE was dechlorinated to cis-1ï¼2-dichloroethylene ï¼cis-1ï¼2-DCEï¼. The relative abundance of Dehalococcoides increased from 1.1% to 53.8% when cis-1ï¼2-DCE was reductively dechlorinated to ethylene. The growth yield of Dehalococcoides gene copy number increased by 1.7×108 copies per 1 µmol Cl- released for the complete reductive dechlorination of PCE to ethylene. The results indicated that Dehalobacter and Dehalococcoides cooperated to completely detoxify PCE. When TCE was used as the only electron acceptorï¼ the relative abundance of Dehalococcoides increased from ï¼29.1 ±2.4ï¼% to ï¼7.7 ±0.2ï¼%ï¼ and gene copy number increased by ï¼1.9 ±0.4ï¼×108 copies per 1 µmol Cl- releasedï¼ after dechlorinating 222.8 µmol of TCE to ethylene. The 16S rRNA gene sequence of Dehalococcoides LWT1ï¼ the main functional dehalogenating bacterium in enrichment culture W-1ï¼ was obtained using PCR and Sanger sequencingï¼ and it showed 100% similarity with the 16S rRNA gene sequence of D. mccartyi strain 195. The anaerobic microbial consortium W-1 was also bioaugmented into the groundwater contaminated by TCE at a concentration of 418.7 µmol·L-1. The results showed that ï¼69.2 ±9.8ï¼% of TCE could be completely detoxified to ethylene within 28 days with a dechlorination rate of ï¼10.3 ±1.5ï¼ µmol·ï¼L·dï¼-1. This study can provide the microbial resource and theoretical guidance for the anaerobic microbial remediation in PCE or TCE-contaminated groundwater.
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Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Tetracloroetileno
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Tricloroetileno
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Chloroflexi
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Dicloretos de Etileno
Limite:
Humans
Idioma:
Zh
Revista:
Huan Jing Ke Xue
Ano de publicação:
2024
Tipo de documento:
Article
País de afiliação:
China