Abstract

Among different xenobiotics, phenol is a man made as well as a naturally occurring aromatic compound and an important intermediate in the biodegradation of natural and industrial aromatic compounds. The investigation was undertaken to isolate, characterize and exploit phenol degrading bacteria from sewage treatment plant (STP) (artificial ecosystem having diverse group of bacteria which are adapted to different aromatic pollutant and capable to degrade xenobiotic aromatic organic pollutants). Out of five different phenol degrading bacteria, one potent strain (IS-3) was identified as Citrobacter freundii with maximum degradation capacity of 1000 ppm phenol in three days under in vitro studies. Phenol degradation performance was greatly influenced by different physical factors like incubation temperature, supplemented glucose, nitrogen source, NaCl and pH of the growth medium. The maximum phenol degradation was observed at incubation temperature of 33°C, 7.5 pH of the medium, 0.1 gl^-1 of NaCl, 0.25 gl^-1 of glucose and 0.25 gl^-1 of ammonium sulphate. We report in this study that the identified potential strain (IS-3) can be used for treatment of phenol contaminated waste water maintaining above the mentioned optimum factors for faster degradation of the phenol contaminated industrial effluents.

Key words: Xenobiotics, phenol, bio-degradation.