Trichloroethylene cometabolism

Aerobic biodegradation of trichloroethylene occurs by cometabolism with aromatie eompounds (Ensley 1991) and thus requires a cosubstrate such as phenol (Nelson et al. 1987, 1988) or toluene (Fan and Scow 1993). Trichloroethylene degradation by toluene-degrading baeteria has been demonstrated in the presence, but not absence, of toluene (Mu and Scow 1994). Isoprene, a structural analog of trichloroethylene, has also been used as a cosubstrate for triehloroethylene oxidation by some bacteria (Ewers et al. 1990). One source of inhibition of degradation in the absence of cosubstrate may be the toxieity of triehloroethylene itself to indigenous bacteria. 

Alvarez-Cohen L, McCarty PL. 1991b. Product toxicity and cometabolic competitive inhibition modeling of chloroform and trichloroethylene transformation by methanotrophic resting cells. Appl Environ Microbiol 57 1031-1037. 

Hopkins GD, PL McCarty (1995) Field evaluation of in situ aerobic cometabolism of trichloroethylene and three dichloroethylene isomers using phenol and toluene as primary substrates. Environ Sci Technol 29 1628-1637. 

McCarty PL, MN Goltz, GD Hopkins, ME Dolan, IP Allan, BT Kawakami, TJ Carrothers (1998) Full-scale evaluation of in situ cometabolic degradation of trichloroethylene in groundwater through toluene injection. Environ Sci Technol 32 88-100. 

Shih C-C, ME Davey, J Zhou, JM Tiedje, CS Criddle (1996) Effects of phenol feeding pattern on microbial community structure and cometabolism of trichloroethylene. Appl Environ Microbiol 62 2953-2960. Somsamak P, HH Richnow, MM Haggblom (2005) Carbon isotope fractionation during anaerobic biotransformation of methyl ferf-butyl ether and ferf-amyl methyl ether. Environ Sci Technol 39 103-109. Somsamak P, RM Cowan, MM Haggblom (2001) Anaerobic biotransformation of fuel oxygenates under sulfate-reducing conditions. EEMS Microbiol Ecol 37 259-264. 

Trichloroethylene L,G Biooxidation by cometabolization with methane or ammonium... 

Chang, W.-K., and C. S. Criddle, Experimental evaluation of a model for cometabolism Prediction of simultaneous degradation of trichloroethylene and methane by a methanotrophic mixed culture , Biotech. Bioeng., 56,492-501 (1997). 

Xenobiotic compounds are usually attacked by enzymes whose primary function is to react with other compounds, a process that provides neither carbon nor energy called cometabolism. Cometabolism usually involves relatively small modifications of the substance that is cometabolized (the secondary substrate), compared to the primary substrate. The enzymes that carry out cometabolism tend to be relatively nonspecific. As an environmentally significant example of cometabolism, at least one strain of bacteria degrades trichloroethylene with an enzyme system that acts predominantly on phenol. The enzyme activity can be induced by exposure to phenol, after which it acts on trichloroethylene. 

Hyman MR, Arp DJ (1995) Effects of ammonia on the de novo synthesis of polypeptides in cells of Nitrosomonas europaea denied ammonia as an energy source. J Bacterid 177 4974-4979 Hyman MR, Russel SA, Ely RL, Williamson KJ, Arp DJ (1995) Inhibition, inactivation, and recovery of ammonia-oxidizing activity in cometabolism of trichloroethylene by Nitrosomonas europaea. Appl Environ Microbiol 61 1480-1487 Hyman MR, Wood PM (1983) Methane oxidation by Nitrosomonas europaea. Biochem J 212 31-37... 

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