Journal of Bioremediation & Biodegradation

Abstrait

Aromatic Hydrocarbon Degrading Fungi Inhabiting the Phyllosphere ofOrnamental Plants on Roadsides of Urban Areas in Sri Lanka

Undugoda LJS, Kannangara S and Sirisena DM

The phyllosphere of Ixora chinensis, Ervatamia divaricata, Hibiscus rosa-sinensis and Amaranthus cruentus, which are highly abundant on roadsides of five polluted areas in Sri Lanka (Colombo Fort, Maradana, Orugodawattha, Panchikawattha and Sapugaskanda) were rich in aromatic hydrocarbon (AH) degrading phyllosphere fungi compared to the plants from the less polluted site. HPLC results revealed significantly higher concentrations of phenanthrene, naphthalene, toluene and xylene concentrations in the phyllosphere of these plants collected from the five polluted sites, promoting the colonization of AH degrading fungal population. In fact, the phyllosphere of Ixora chinensis collected from Colombo Fort had the highest AH degrading fungal population. Also the phyllosphere of these plants had the highest phenanthrene (96.1 ng/g), naphthalene (160 ng/g), toluene (85.66 ng/g) and xylene (54.39 ng/g) concentrations. Thirty eight such fungal strains were isolated from the leaves of four ornamental plants collected from the above five polluted sites. Plate assay results showed, out of them twenty four phyllosphere fungal strains had at least one AH compound utilization ability. However, according to the HPLC and colorimetric assays, only nineteen fungal strains had the AH degradation ability. Then the best AH degrading phyllosphere fungi were identified into species levels (Penicillium oxalicum, Aspergilllus aculeatus, Aspergillus oryzea and Colletrotrichum siamense) using molecular techniques followed by PCR amplification, amplicons sequencing and BLASTN search. Penicillium oxalicum was the best naphthalene and phenanthrene degrader with 80% and 96% degradation abilities respectively. Significantly higher toluene degradation was demonstrated by Aspergilllus aculeatus. Colletrotrichum siamense showed the significantly highest xylene degradation ability (68.9%). These fungi were the dominant species in the highly polluted sites, Maradana and Colombo Fort.