BIODEGRADATION OF DICHLOROPHENOLS BY BJERKANDERA ADUSTA AND LENTINUS SQUARROSULUS AND EXTRACELLULAR LIGNINOLYTIC ENZYME ACTIVITIES.

Dichlorophenols are a group of toxic compounds that have been widely used as biocides. Fifty fungal strains were screened for their potential to tolerance with 2,3-dichlorophenol, 2,5-dichlorophenol and 3,4-dichlorophenol on solid medium supplemented with 2% malt extract (MEA). Growth rate (mmday-1) was determined at three concentrations (0.10, 0.15 and 0.2 mM) of all the three dichlorophenols. From the fifty fungal strains only Bjerkandera adusta and Lentinus squarrosulus were able to tolerate all the three dichlorophenols (DCPs). These white-rot fungi (WRF) were chosen for liquid medium studies for the biodegradation of DCPs and ligninolytic enzyme activity at 0.10 mM concentration over the period of 20 days. Both varieties completely degrade all the three DCPs. Aryl Alcohol Oxidase (AAO) is the main oxidase enzyme in B. adusta while laccase plays important role in L. squarrosulus. MnP (Manganese peroxidase) showed good activity with both varieties. The DCPs biodegradation potential of the WRF positively correlated with their potential to express ligninolytic enzymes such as laccase, AAO, MnP and lignin peroxidase (LiP). These fungal strains were capable to degrade DCPs and could be used for bioremediation applications on large scale.