Screening and Characterization of Polycyclic Aromatic Hydrocarbons Tolerant Fungi from Petrochemical Refinery Effluent

Abstract

Fungi were isolated from effluent released by petrochemical refinery and screened for their tolerance to 50 mg/L concentration of naphthalene, phenanthrene and pyrene under agitation condition of 150 rpm and ambient temperature over a period of 21 days. Samples were analysed for residual PAH concentrations using HPLC and tolerance ability were calculated in percentages. Fungal growth in mineral salt medium supplemented with PAH was measured in dry weight of mycelial biomass was used as index for assessing their tolerance ability. Out of the 22 fungi isolated, only four were identified as Aspergillus, Talaromyces, Fusarium and Trichoderma species to exhibit tolerance to naphthalene (94.6, 96.9, 99.7 and 99.8%), phenanthrene (91.1, 92.2, 99.5 and 99.8%) and pyrene (89.4, 90.5, 92,6 and 94.2%) respectively. Low molecular weight PAHs (naphthalene and phenanthrene) were better tolerated compared to high molecular weight pyrene. Based on findings made in this study, the four isolates with higher tolerance to PAHs could be recommended for bioremediation of PAH contaminated environments.