title: Bioremediation of 1,2-dichloroethane contaminated groundwater: Microcosm and microbial diversity studies.
abstract: In this study, the effectiveness of bioremediating 1,2-dichloroethane (DCA)-contaminated groundwater under different oxidation-reduction processes was evaluated. Microcosms were constructed using indigenous bacteria and activated sludge as the inocula and cane molasses and a slow polycolloid-releasing substrate (SPRS) as the primary substrates. Complete DCA removal was obtained within 30 days under aerobic and reductive dechlorinating conditions. In anaerobic microcosms with sludge and substrate addition, chloroethane, vinyl chloride, and ethene were produced. The microbial communities and DCA-degrading bacteria in microcosms were characterized by 16S rRNA-based denatured-gradient-gel electrophoresis profiling and nucleotide sequence analyses. Real-time polymerase chain reaction was applied to evaluate the variations in Dehalococcoides spp. and Desulfitobacterium spp. Increase in Desulfitobacterium spp. indicates that the growth of Desulfitobacterium might be induced by DCA. Results indicate that DCA could be used as the primary substrate under aerobic conditions. The increased ethene concentrations imply that dihaloelimination was the dominate mechanism for DCA biodegradation.
authors: Institute of Environmental Engineering, National Sun Yat-Sen University, Kaohsiung, Taiwan.
authors: S Y
authors: SY
authors: Wang
authors: Institute of Environmental Engineering, National Sun Yat-Sen University, Kaohsiung, Taiwan.
authors: Y C
authors: YC
authors: Kuo
authors: Bioenvironmental Engineering Department, Chung Yuan University, Chung Li, Taiwan.
authors: Y Z
authors: YZ
authors: Huang
authors: Deaprtment of Biological Science, National Sun Yat-Sen University, Kaohsiung, Taiwan.
authors: C W
authors: CW
authors: Huang
authors: Institute of Environmental Engineering, National Sun Yat-Sen University, Kaohsiung, Taiwan. Electronic address: jkao@mail.nsysu.edu.tw.
authors: C M
authors: CM
authors: Kao
mesh_terms: D001673:Biodegradation, Environmental; D041862:Chloroflexi / Q000378:metabolism*; D045858:Desulfitobacterium / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D005018:Ethyl Chloride / Q000378:metabolism; D005025:Ethylene Dichlorides / Q000378:metabolism*; D005030:Ethylenes / Q000378:metabolism; D060587:Groundwater; D010084:Oxidation-Reduction; D012336:RNA, Ribosomal, 16S; D012722:Sewage / Q000382:microbiology; D014752:Vinyl Chloride / Q000378:metabolism; D014874:Water Pollutants, Chemical / Q000378:metabolism*
chemical_list: D005025:Ethylene Dichlorides; D005030:Ethylenes; D012336:RNA, Ribosomal, 16S; D012722:Sewage; D014874:Water Pollutants, Chemical; D005018:Ethyl Chloride; C024565:ethylene dichloride; C036216:ethylene; D014752:Vinyl Chloride
keywords: 1,2-Dichloroethane (DCA); Bioremediation; Groundwater contamination; Real-time polymerase chain reaction (PCR)