ANAEROBIC BIODEGRADABILITY OF ALKYLBENZENES AND PHENOL BY LANDFILL DERIVED MICROORGANISMS

The objectives of this research were to evaluate the anaerobic biodegr adability of benzene, toluene, ethylbenzene, xylenes, phenol and p-cre sol by microorganisms present in decomposing refuse and to study the e ffects of environmental conditions, pertinent to landfills, on the ana erobic degradation of phenol and p-cresol by refuse derived microbial consortia. Microbial inocula were derived from refuse from both landfi lls and laboratory reactors. While toluene biodegradation was only mea sured with one inoculum, broad degradation for phenol and p-cresol was measured. Cultures enriched on refuse were then derived from two samp les to evaluate conservation of degradative activity against phenol. I n one enrichment, phenol degrading activity was maintained after 6 mon ths, while this activity decreased in a second culture. Phenol and p-c resol enrichment cultures also exhibited activity against other hydrox yl-substitute aromatics but not mono-chlorinated phenols. Cellulosic c arbon and soluble trace constituents extracted from Fresh refuse stimu lated phenol degradation with one enrichment. However; the cellulosic carbon was inhibitory to the other phenol and p-cresol enrichment cult ures. The pH optima for all cultures were between 6.5 and 7.0, Finally , a high concentration of acetate prevented the efficient removal of b enzoate and consequently inhibited phenol degradation, Landfills were shown to be a habitat harboring anaerobic microbial populations capabl e of degrading toluene and hydroxyl-substitute aromatics, suggesting t hat contaminant degradation may be maximized with proper landfill mana gement. (C) 1998 Federation of European Microbiological Societies. Pub lished by Elsevier Science B.V.