Transformation capacities of chlorinated organics by mixed cultures enriched on methane, propane, toluene, or phenol
Article first published online: 19 FEB 2004
Copyright © 1995 John Wiley & Sons, Inc.
Biotechnology and Bioengineering
Volume 45, Issue 5, pages 440–449, 5 March 1995
How to Cite
Chang, H.-L. and Alvarez-Cohen, L. (1995), Transformation capacities of chlorinated organics by mixed cultures enriched on methane, propane, toluene, or phenol. Biotechnol. Bioeng., 45: 440–449. doi: 10.1002/bit.260450509
- Issue published online: 19 FEB 2004
- Article first published online: 19 FEB 2004
- Manuscript Accepted: 9 NOV 1994
- Manuscript Received: 30 JUN 1994
- transformation capacity;
- product toxicity;
- oxygenase enzymes;
- chlorinated organics;
The degradation of trichloroethylene (TCE), chloroform (CF), and 1,2-dichloroethane (1,2-DCA) by four aerobic mixed cultures (methane, propane, toluene, and phenol oxidizers) grown under similar chemostat conditions was measured. Methane and propane oxidizers were capable of degrading both saturated and unsaturated chlorinated organics (TCE, CF, and 1,2-DCA). Toluene and phenol oxidizers degraded TCE but were not able to degrade CF, 1,2-DCA, or other saturated organics. None of the cultures tested were able to degrade perchloroethylene (PCE) or carbon tetrachloride (CC4). For the four cultures tested, degradation of each of the chlorinated organics resulted in cell inactivation due to product toxicity. In all cases, the toxic products were rapidly depleted, leaving no toxic residues in solution. Among the four tested cultures, the resting cells of methane oxidizers exhibited the highest transformation capacities (Tc) for TCE, CF, and 1,2-DCA. The Tc for each chlorinated organic was observed to be inversely proportional to the chlorine carbon ratio (Cl/C). The addition of low concentrations of growth substrate or some catabolic intermediates enhanced TCE transformation capacities and degradation rates, presumably due to the regeneration of reducing energy (NADH); however, addition of higher concentrations of most amendments reduced TCE transformation capacities and degradation rates. Reducing energy limitations and amendment toxicity may significantly affect Tc measurements, causing a masking of the toxicity associated with chlorinated organic degradation. © 1995 John Wiley & Sons, Inc.