RESPONSE OF PHENOL-DEGRADING PSEUDOMONAS-PICTORUM TO CHANGING LOADS OF PHENOLIC-COMPOUNDS

Aromatic compounds exist in a variety of biogenic products, which are released into the environment. Toxic and hazardous chemicals like pest icides used in agriculture or those derived from industrial processes find their way into a variety of environments. Alterations in chemical structure modify the susceptibility of organic compounds to biodegrad ation. Phenol and substituted phenols are present in the wastewater ar ising from number of industries. Therefore, a detailed study was carri edout to determine the growth and tolerance limit of phenol degrading P.pictorum towards substituted phenols. In addition, the ability of P. pictorum to degrade various concentrations of other phenolic compounds was also investigated. The nature of the substituent as well as the p osition of the substituent in the benzene ring, in relation to phenoli c -OH group exerted a greater influence in deciding the degradative ab ility. 4-nitrophenol showed less growth compared to chlorophenols due to resonance effect of -NO2, which decreases induction of phenol hydro xylase. In the case of chlorophenols, the order of degradability was f ound to be 4-CP > 2-CP > 3-CP. Presence of more than one substituent i n the benzene ring exerts steric effect, there by influencing phenol d egradation. In the case of, 2-carboxy 4-sulphonyl phenol, the rate of growth was much less compared to phenol, there by reducing phenol degr adation.