Asian Journal of Microbiology, Biotechnology & Environmental Sciences Paper

BIODEGRADATION OF MONOCHLOROPHENOLS AND CRESOLS IN MIXTURES

J.B. CHAWLA AND A.O. INGLE

Abstract

Acinetobacter sp. strain A-2 was isolated from soil by enrichment technique. It was found to utilize all the three isomers of monochlorophenols and cresols. The relative rates of degradation of m onochlorophenols were 4-chlorophenol (4-CP) > 3-chlorophenol (3-CP) > 2-chlorophenol (2-CP); while degradation of cresols occurred in the order p-cresol > m-cresol > o-cresol. Contrary to the several reported findings it was 2-CP and not 3-CP which exhibited a significant resistance during degradation. p-cresol was preferentially utilized when present along with 2-CP in the medium. However preferential utilization of 3- CP/4-CP was observed when incorporated along with p-cresol in mixtures. In the mixture containing 25011M 3-CP/4-CP and 200pM p-cresol the degradation rate of 3-CP/4-CP as well as p-cresol slowed down. Incorporation of o-cresol/m-cresol in the medium containing 4-CF also resulted in slower degradation of 'total phenols'. Inclusion of yeast extract in the medium increased the biomass concentration and accelerated the degradation rates of monochlorophenols as well as cresols in most of the cases.