期刊
PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES
卷 368, 期 1616, 页码 -出版社
ROYAL SOC
DOI: 10.1098/rstb.2012.0326
关键词
Shewanella; tetrachloroethene; trichloroethene; reductive dehalogenase; marine sediment
类别
资金
- Strategic Environmental Research Defense Project (SERDP) [ER-1588]
- ENI grant
- German Research Foundation (Deutsche Forschungsgemeinschaft) [Lo 1597/1-1]
The genome sequence of psychrophilic Shewanella sediminis revealed the presence of five putative reductive dehalogenases (Rdhs). We found that cell extracts of pyruvate/fumarate-grown S. sediminis cells catalysed reduced methyl viologen-dependent reductive dechlorination of tetrachloroethene (PCE) to trichloroethene (TCE) at a specific activity of approximately 1 nmol TCE min(-1) (mg protein)(-1). Dechlorination of PCE followed Michaelis-Menten kinetics with an apparent K-m of 120 mu M PCE. No PCE dechlorination was observed with heat-denatured extract or when cyanocobalamin was omitted from the growth medium; however, the presence of PCE in the growth medium increased PCE transformation rates. Analysis of mutants carrying in-frame deletions of all five Rdhs encoding genes showed that only deletion of Ssed_3769 resulted in the loss of PCE dechlorination activity suggesting that Ssed_3769 is a functional Rdh. This is the first study to show reductive dechlorination activity of PCE in a sediment-dwelling Shewanella species that may be important for linking the flux of organohalogens to organic carbon via reductive dehalogenation in marine sediments.
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