Health & Environmental Research Online (HERO)


Print Feedback Export to File
5472024 
Journal Article 
Biodegradation of Xenobiotics by Specific Bacteria: Research and Applications 
Keuning, S; Janssen, DB; Witholt, B 
1989 
HAZARDOUS MATERIALS CONTROL RESEARCH INST 
GREENBELT 
109-117 
English 
WOS:A1989BQ17R00017 
Investigations of the enzymology, genetics, and physiology of the bacterial degradation of xenobiotics should contribute significantly to the development of practical biotreatment. The utilization of a given pollutant by an organism which has the necessary genetic information to express relevant enzymes to degrade the pollutant may be limited by local environmental conditions. Genetic engineering experiments may result in addition bacterial stains capable of degrading priority pollutants. A critical step in the microbial metabolism of chlorinated compounds is dehalogenation. Five dehalogenation mechanisms have been observed in aerobic bacteria. Hydrolytic dehalogenation is well documented for the conversion of 2-halocarboxylic acids by bacteria that utilize chloropropionate or chloroacetate for growth. Some dehalogenases have been isolated and produced in synthetic form. Compounds with vinylic halogens, trihalomethanes, and several other highly chlorinated aliphatics may be degraded by oxidative conversion mediated by monooxygenases produced by methanotrophic bacteria. Pollutants that are not presently biodegradable may be recalcitrant due to lack of necessary bacterial enzymes to utilize the pollutant, or accumulation of toxic intermediates which inhibit degrading microorganisms. An important goal of research on the biodegradation of chlorinated hydrocarbons will be to achieve biological removal of chlorinated hydrocarbons by microorganisms that rely on cometabolic conversion. Anaerobic conversions that cause dechlorination have been described for several highly chlorinated compounds, such as carbon tetrachloride, perchloroethylene, and 1,1,1- trichloroethane. These conversions could become very important for removing chlorinated aliphatics at low redox potential in anaerobic subsurface environments. (See also W91-03097) (Geiger-PTT) 
Water Resources Abstracts; Bacteria Biodegradation Dehalogenation Microbial degradation; Priority pollutants Waste treatment Wastewater treatment; Biological wastewater treatment Chlorinated hydrocarbons Genetic; engineering Oxidation 
0-944989-93-4 
2ND NATIONAL CONF ON BIOTREATMENT : THE USE OF MICROORGANISMS IN THE TREATMENT OF HAZARDOUS MATERIALS AND HAZARDOUS WASTES 
WASHINGTON, DC