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Applied and Environmental Microbiology, August 2000, p. 3535-3542, Vol. 66, No. 8
Department of Civil and Environmental
Engineering, University of Illinois, Urbana, Illinois
61808,1 and Department of Environmental
Engineering and Science, Clemson University, Clemson, South Carolina
296342
Received 18 October 1999/Accepted 8 June 2000
An aerobic enrichment culture was developed by using vinyl chloride
(VC) as the sole organic carbon and electron donor source. VC
concentrations as high as 7.3 mM were biodegraded without apparent inhibition. VC use did not occur when nitrate was provided as the
electron acceptor. A gram-negative, rod-shaped, motile isolate was
obtained from the enrichment culture and identified based on
biochemical characteristics and the sequence of its 16S rRNA gene as
Pseudomonas aeruginosa, designated strain MF1. The observed yield of MF1 when it was grown on VC was 0.20 mg of total suspended solids (TSS)/mg of VC. Ethene, acetate, glyoxylate, and glycolate also
served as growth substrates, while ethane, chloroacetate, glycolaldehyde, and phenol did not. Stoichiometric release of chloride
and minimal accumulation of soluble metabolites following VC
consumption indicated that the predominant fate for VC is
mineralization and incorporation into cell material. MF1 resumed
consumption of VC after at least 24 days when none was provided, unlike
various mycobacteria that lost their VC-degrading ability after brief periods in the absence of VC. When deprived of oxygen for 2.5 days, MF1
did not regain the ability to grow on VC, and a portion of the VC was
transformed into VC-epoxide. Acetylene inhibited VC consumption by MF1,
suggesting the involvement of a monooxygenase in the initial step of VC
metabolism. The maximum specific VC utilization rate for MF1 was 0.41 µmol of VC/mg of TSS/day, the maximum specific growth rate was
0.0048/day, and the Monod half-saturation coefficient was 0.26 µM. A
higher yield and faster kinetics occurred when MF1 grew on ethene. When
grown on ethene, MF1 was able to switch to VC as a substrate without a
lag. It therefore appears feasible to grow MF1 on a nontoxic substrate
and then apply it to environments that do not exhibit a capacity for
aerobic biodegradation of VC.
0099-2240/00/$04.00+0
Copyright © 2000, American Society for Microbiology. All rights reserved.
Characterization of an Isolate That Uses Vinyl
Chloride as a Growth Substrate under Aerobic Conditions

*
Corresponding author. Mailing address: Department of
Environmental Engineering and Science, Box 349019, Clemson University, Clemson, SC 29634-0919. Phone: (864) 656-5566. Fax: (864) 656-0672. E-mail: dfreedm{at}clemson.edu.
Present address: Department of Environmental Engineering and
Science, Clemson University, Clemson, SC 29634.
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