Publication Date:
2022-05-26
Description:
Author Posting. © American Society for Microbiology, 2002. This article is posted here by permission of American Society for Microbiology for personal use, not for redistribution. The definitive version was published in Applied and Environmental Microbiology 68 (2002): 1728-1734, doi:10.1128/AEM.68.4.1728-1734.2002.
Description:
The strain Burkholderia cepacia G4 aerobically mineralized trichloroethene (TCE) to CO2 over a time period of ~20 h. Three biodegradation experiments were conducted with different bacterial optical densities at 540 nm (OD540s) in order to test whether isotope fractionation was consistent. The resulting TCE degradation was 93, 83.8, and 57.2% (i.e., 7.0, 16.2, and 42.8% TCE remaining) at OD540s of 2.0, 1.1, and 0.6, respectively. ODs also correlated linearly with zero-order degradation rates (1.99, 1.11, and 0.64 µmol h-1). While initial nonequilibrium mass losses of TCE produced only minor carbon isotope shifts (expressed in per mille {delta}13CVPDB), they were 57.2, 39.6, and 17.0{per thousand} between the initial and final TCE levels for the three experiments, in decreasing order of their OD540s. Despite these strong isotope shifts, we found a largely uniform isotope fractionation. The latter is expressed with a Rayleigh enrichment factor, {varepsilon}, and was -18.2 when all experiments were grouped to a common point of 42.8% TCE remaining. Although, decreases of {varepsilon} to -20.7 were observed near complete degradation, our enrichment factors were significantly more negative than those reported for anaerobic dehalogenation of TCE. This indicates typical isotope fractionation for specific enzymatic mechanisms that can help to differentiate between degradation pathways.
Description:
This work was conducted with finances from the German
Academic Exchange Service (DAAD), the Swiss National Science
Foundation, and EPSRC grants (GR/M26374 and GR/L85183), as
well as support of the Department of Education (Northern Ireland)
and the QUESTOR Industrial Board.
Keywords:
Burkholderia cepacia G4
;
Trichloroethene
;
Degradation pathways
Repository Name:
Woods Hole Open Access Server
Type:
Article
Format:
523832 bytes
Format:
application/pdf
Permalink
