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Research has been conducted on the aerobic bacterium which can grow on cis-dichloroethene using it as an energy and carbon source. The isolation of this bacterium has been carried out via enrichment culture and the results indicate that cis-dichloroethene contains enough energy to support aerobic bacterium growth.

Summary: Chemoautotrophic bacteria from the SUP05 clade often dominate anoxic waters within marine oxygen minimum zones (OMZs) where they use energy gained from the oxidation of reduced sulfur to fuel carbon fixation. Some of these SUP05 bacteria are facultative aerobes that can use either nitrate or oxygen as a terminal electron acceptor making them ideally suited to thrive at the boundaries of OMZs where they experience fluctuations in dissolved oxygen (DO). SUP05 metabolism in these regions, and therefore the biogeochemical function of SUP05, depends largely on their sensitivity to oxygen. We evaluated growth and quantified differences in gene expression in Ca. T. autotrophicus strain EF1 from the SUP05 clade under high DO (22 μM), anoxic, and low DO (3.8 μM) concentrations. We show that strain EF1 cells respire oxygen and nitrate and that cells have higher growth rates, express more genes, and fix more carbon when oxygen becomes available for aerobic respiration. Evidence that facultatively aerobic SUP05 are more active and respire nitrate when oxygen becomes available at low concentrations suggests that they are an important source of nitrite across marine OMZ boundary layers. [ABSTRACT FROM AUTHOR]

Polychlorinated biphenyls (PCBs) contaminate 19% of US Superfund sites and represent a serious risk to human and environmental health. One promising strategy to remediate PCB-contaminated sediments utilizes organohalide-respiring bacteria (OHRB) that dechlorinate PCBs. However, functional genes that act as biomarkers for PCB dechlorination processes (i.e., reductive dehalogenase genes) are poorly understood. Here, we developed anaerobic sediment microcosms that harbor an OHRB community dominated by the genus Dehalococcoides. During the 430-day microcosm incubation, Dehalococcoides 16S rRNA sequences increased two orders of magnitude to 107 copies/g of sediment, and at the same time, PCB118 decreased by as much as 70%. In addition, the OHRB community dechlorinated a range of penta- and tetra-chlorinated PCB congeners including PCBs 66, 70 + 74 + 76, 95, 90 + 101, and PCB110 without exogenous electron donor. We quantified candidate reductive dehalogenase (RDase) genes over a 430-day incubation period and found rd14, a reductive dehalogenase that belongs to Dehalococcoides mccartyi strain CG5, was enriched to 107 copies/g of sediment. At the same time, pcbA5 was enriched to only 105 copies/g of sediment. A survey for additional RDase genes revealed sequences similar to strain CG5's rd4 and rd8. In addition to demonstrating the PCB dechlorination potential of native microbial communities in contaminated freshwater sediments, our results suggest candidate functional genes with previously unexplored potential could serve as biomarkers of PCB dechlorination processes. [ABSTRACT FROM AUTHOR]

The vinyl chloride (VC) adaptation in two variants (JS623-E and JS623-T) of the ethene-oxidizing Mycobacterium strain JS623 was explored to understand the mutations in the alkene/epoxide catabolic genes responsible for VC adaptation. The study results provide insight into the genetic change associated with the transition from cometabolic to growth-linked VC oxidation in bacteria.

A bioinformatic and phenotypic analysis is described that has revealed diverse metabolic capabilities of JS666 that might be useful for bioremediation and biocatalysis. The roles of mobile genetic elements in shaping the genome and metabolic abilities of the bacterium are described.

A peptide mass fingerprinting (PMF) approach is used to identify enzymes expressed in response to vinyl chloride, ethene, and epoxyethane by Nocardioides sp. strain JS614. It is found that PMF extends the use of matrix-assisted laser desorption-ionization time of flight mass spectrometry as a tool to enhance characterization of biodegradation pathways.