CLASSICAL AND NEW ASPECTS IN DEGRADATION OF AROMATIC XENOBIOTICS

Organic chemical mixtures are prevalent in waste waters from industrial and municipal sources as well as in contaminated groundwater. Phenols are pollutants found in wastewaters from oil refineries, chemical plants, explosives, resins and coke manufacture, coal conversion, pesticide and textile industries. The main contaminants of refinery wastewater include phenols, polycyclic aromatic hydrocarbons (PAHs) as well as heavy metals. Among these toxic pollutants, phenols are considered to be the most hazardous ones, and they are certainly the most difficult to remove. Phenolic compounds are toxic at relatively low concentration. Because of these low concentrations the most suitable methods for their removal are the microbial ones. The present work is a review of biodegradation of phenol. Degradation of phenol occurs as a result of the activity of a large number of microorganisms including bacteria, fungi and actinomycetes. There are reports on ma33ny microorganisms capable of degrading phenol through the action of variety of enzymes. These enzymes may include oxygenases, hydroxylases, peroxidases, tyrosinases, oxidases etc. Batch experiments were carried out in a different bioreactors. Biodegradation of organic chemicals by microbes using pure cultures can produce toxic intermediates. This problem may be overcome by the use of mixed cultures that have a wider spectrum of metabolite degradation properties. In this revew we described also some new technology for biodegradation of phenol like: different immobilization, FISH (Fluorescence in-situ hybridization) analysis, nanobiotechnologies and etc. Key words: phenol, biodegradation, microorganisms, enzymes, immobilization, FISH analysis, nanobiotechnologies