Affiliation:
1. Division of Environmental Science and Engineering, National University of Singapore, Singapore 117576, Republic of Singapore
Abstract
ABSTRACT
In an attempt to understand the microorganisms involved in the generation of
trans
-1,2-dichloroethene (
trans
-DCE), pure-culture “
Dehalococcoides
” sp. strain MB was isolated from environmental sediments. In contrast to currently known tetrachloroethene (PCE)- or trichloroethene (TCE)-dechlorinating pure cultures, which generate
cis
-DCE as the predominant product,
Dehalococcoides
sp. strain MB reductively dechlorinates PCE to
trans
-DCE and
cis
-DCE at a ratio of 7.3 (±0.4):1. It utilizes H
2
as the sole electron donor and PCE or TCE as the electron acceptor during anaerobic respiration. Strain MB is a disc-shaped, nonmotile bacterium. Under an atomic force microscope, the cells appear singly or in pairs and are 1.0 μm in diameter and ∼150 nm in depth. The purity was confirmed by culture-based approaches and 16S rRNA gene-based analysis and was corroborated further by putative reductive dehalogenase (RDase) gene-based, quantitative real-time PCR. Although strain MB shares 100% 16S rRNA gene sequence identity with
Dehalococcoides ethenogenes
strain 195, these two strains possess different dechlorinating pathways. Microarray analysis revealed that 10 putative RDase genes present in strain 195 were also detected in strain MB. Successful cultivation of strain MB indicates that the biotic process could contribute significantly to the generation of
trans
-DCE in chloroethene-contaminated sites. It also enhances our understanding of the evolution of this unusual microbial group,
Dehalococcoides
species.
Publisher
American Society for Microbiology
Subject
Ecology,Applied Microbiology and Biotechnology,Food Science,Biotechnology
Cited by
100 articles.
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