The Ligninolytic and Biodegradation Potential ...

Extracellular peroxidases and laccases catalyze the breakdown of organic pollutants via free radical–mediated reactions. In this study, the ligninolytic activities of selected strains of Pleurotus ostreatus were determined in a nitrogen-sufficient liquid medium. In order to determine the effect of temperature in ligninolytic activities, the white rot fungi were incubated at different cultivation temperatures (15, 20, 25 and 30οC). The activities of manganese peroxidase and laccase were determined but no lignin peroxidase was detected for all strains. Significant differences were revealed between the strains of the same species. Degenerate primers corresponding to the copper-binding regions in N-terminal domains of known basidiomycetes were used to detect laccase gene. The strain of Pleurotus ostreatus, which showed the greatest ligninolytic potential, was used for the biodegradation of lindane in agitated liquid cultures. An orthogonal Central Composite Design of experiments was used to construct second order response surfaces with the fungus growth, final pH and lindane biodegradation as optimization parameters.