Chloroethene degradation and expression of Dehalococcoides dehalogenase genes in cultures originating from Yangtze sediments

Abstract

The anaerobic Dehalococcoides spp. is the only microorganism known to completely dechlorinate the hazardous compounds tetrachloroethene (PCE) or trichloroethene (TCE) via dichloroethene (DCE) and vinyl chloride (VC) to the terminal product, ethene. In this study, growth of Dehalococcoides spp. (DHC) and the expression of DHC dehalogenase genes were demonstrated for Yangtze enrichment cultures. Reductive dechlorination of chloroethenes occurred in Yangtze sediment without the addition of any external auxiliary substrates. All Yangtze enrichment cultures completely dechlorinated PCE and cis-DCE to ethene. To investigate expression of the dehalogenase genes pceA, tceA, vcrA, and bvcA, a protocol for messenger RNA (mRNA) extraction followed by reverse transcription and quantitative PCR analysis was established. During dechlorination, an increase in gene copy numbers of pceA, tceA, and vcrA was observed. However, temporary formation of mRNA was only measured in the case of the dehalogenase genes tceA and vcrA. Comparison of DHC dehalogenase patterns indicated that the Yangtze DHC community does not match any of the previously published enrichment cultures that were obtained from contaminated areas in the USA or Europe.

A study of chlorinated solvent contamination of the aquifers of an industrial area in central Italy: a possibility of bioremediation

“…Many studies demonstrated that Dehalococcoides spp. is a bacterial genus known to completely dechlorinate the hazardous compounds PCE and TCE via DCE and VC to the terminal product, ethane ( Aktaş et al, 2012 ; Löffler et al, 2013 ; Kranzioch et al, 2015 ). Recently, Cichocka et al (2010) investigated on reductive dechlorination (RD) of tetrachloroethene to ethene.…”

“…During dechlorination, an increase in gene copy numbers of pceA, tceA , and vcrA , was observed ( Poritz et al, 2013 ; Kranzioch et al, 2015 ).…”

Since 2015 the SinoGerman research project SIGN supports water quality improvement in the Taihu region, China

“…Biodegradation of organic pollutants and nitrogen-containing compounds (nitrate, nitrite, ammonia) as beneficial ecosystem services is investigated by using modern PCR-techniques [19, 20] as well as by isotope fractionation [26–28] within laboratory degradation studies with original Taihu materials. Powerful PCR methods are also used to detect microorganisms having harmful effects such as bacteria with antibiotic resistance genes [29] as well as pathogenic viruses and bacteria, originating e.g.…”

Thematic Issue: Water of the Taihu Lake

“…DDT is a typical organic compound characterized by high bioaccumulability, toxicity, and persistence aquatic environments and is, therefore, important to many lakes. The microbiological transformation of chlorinated pollutants in Yangtze River sediments has been demonstrated recently (Kranzioch et al 2013(Kranzioch et al , 2015. Huang et al (2014a) modeled the effects of environmental variables on short-term spatial changes in phytoplankton biomass in the Lake Taihu.…”