Research Article
Kannangara S, Undugoda L, Raja
Abstract
Application of aromatic hydrocarbon degrading fungi to bioremediate aromatic hydrocarbonic (AH) pollutants is a current trend and many research on the use of such fungi to remediate aromatic hydrocarbonic pollutants in temperate situations have been reported. Bioremediation of these hydrocarbons is through an array of lignolitic and non lignolitic extra cellular enzymes. Therefore, the present investigation attempts to assess lignolytic and non lignolytic enzyme activities of selected phyllosphere aromatic hydrocarbon degrading fungi during the aromatic hydrocarbon degradation. In a previous research aromatic hydrocarbon degrading fungi were isolated from ornamental leaf samples collected from highly urbanized and industrialized areas of Sri Lanka. These fungal species were then selected to evaluate their enzyme activities when degrading aromatic hydrocarbons. They were screened for their manganese dependent peroxidases (Mnp), Lignin peroxidases (Lip) and laccases enzyme activities. Most efficient naphthalene degrading fungi showed Mnp and Lip enzyme activities. The best naphthalene degrader, Penicillium oxalicum showed significantly higher Mnp (26 Uml-1 min-1) activity during naphthalene degradation process. However, phenanthrene degrading phyllosphere fungal strains showed higher laccase activities. Penicillium oxalicum showed significantly higher laccase activity during the phenanthrene degradation showing the same fungal species had different enzyme predominant pathways for different xenobiotics. Same fungal species performed differently for different AH substrates. Mnp was the predominantly used enzyme in the most efficient naphthalene degrading fungal species and phenanthrene degradation of them was manipulated by laccases. The promising results of the present investigation will broaden the perspective of ecofriendly practical application of the above fungal strains at environmental sites where contamination is caused by AHs especially, phenanthrene, naphthalene, toluene and xylene. Also this opens many avenues for conducting future research in the field of bioremediation and biodegradation.