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Isolation of novel bacteria within the Chloroflexi capable of reductive dechlorination of 1,2,3‐trichloropropane
Author(s) -
Yan J.,
Rash B. A.,
Rainey F. A.,
Moe W. M.
Publication year - 2009
Publication title -
environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.954
H-Index - 188
eISSN - 1462-2920
pISSN - 1462-2912
DOI - 10.1111/j.1462-2920.2008.01804.x
Subject(s) - reductive dechlorination , dehalogenase , biology , dehalococcoides , 16s ribosomal rna , vinyl chloride , desulfovibrio , electron acceptor , bacteria , microbiology and biotechnology , medicinal chemistry , chemistry , organic chemistry , biochemistry , biodegradation , gene , genetics , copolymer , polymer
Summary Two strictly anaerobic bacterial strains were isolated from contaminated groundwater at a Superfund site located near Baton Rouge, LA, USA. These strains represent the first isolates reported to reductively dehalogenate 1,2,3‐trichloropropane. Allyl chloride (3‐chloro‐1‐propene), which is chemically unstable, was produced from 1,2,3‐trichloropropane, and it was hydrolysed abiotically to allyl alcohol and also reacted with the sulfide‐ and cysteine‐reducing agents in the medium to form various allyl sulfides. Both isolates also dehalogenated a variety of other vicinally chlorinated alkanes (1,2‐dichloropropane, 1,2‐dichloroethane, 1,1,2‐trichloroethane, 1,1,2,2‐tetrachloroethane) via dichloroelimination reactions. A quantitative real‐time PCR (qPCR) approach targeting 16S rRNA genes indicated that both strains couple reductive dechlorination to cell growth. Growth was not observed in the absence of hydrogen (H 2 ) as an electron donor and a polychlorinated alkane as an electron acceptor. Alkanes containing only a single chlorine substituent (1‐chloropropane, 2‐chloropropane), chlorinated alkenes (tetrachlorothene, trichlorothene, cis ‐dichloroethene, trans ‐dichloroethene, vinyl chloride) and chlorinated benzenes (1‐chlorobenzene and 1,2‐dichlorobenzene) were not dechlorinated. Phylogenetic analysis based on 16S rRNA gene sequence data showed these isolates to represent a new lineage within the Chloroflexi . Their closest previously cultured relatives are ‘Dehalococcoides’ strains, with 16S rRNA gene sequence similarities of only 90%.