Abstract

Polycyclic Aromatic Hydrocarbons (PAH) are organic compounds and the United State Environmental Protection Agency has classified 16 PAHs as toxic, mutagenic and carcinogenic. Phenanthrene is among the 16 PAH compound and it serves as an indicator compound to detect PAH contamination. This study investigated the population of total fungi and the presence of potential Phenanthrene utilizing fungi in surface water and sediment samples of Orashi River in Rivers State, Nigeria using standard methods. Potential phenanthrene utilizing fungi were cultivated using mineral salt medium (MSM) with phenanthrene as the carbon source which was supplied onto the medium using incorporation technique. Samples were inoculated onto MSM using spread plate technique and incubated for 10 days. Extraction of pure cultured Phenanthrene Utilizing Fungi DNA was done using ZR fungal bacterial DNA Prep extraction kit and the extracted DNA was subjected to polymerase chain reaction (PCR). Amplicons was sequenced using Big Dye Terminator Kit. Internal transcribed spacer (ITS) sequences were downloaded into the database of National Centre for Biotechnology Information (NCBI) using Basic Alignment Search Tool – Nucleotide (BLASTN) algorithm. Results revealed that, total fungal counts in the surface water samples of Orashi River ranged from 6.5±0.64×10²CFU/ml to 2.77±3.01×10⁴CFU/ml while the total fungal counts in the sediment samples ranged 1.20±1.13×10⁴ – 2.30±2.40×10⁴CFU/g. However, potential Phenanthrene utilizing fungi were not recovered from the surface water samples. While potential Phenanthrene utilizing fungi counts in the sediment samples ranged from 6.5±0.64×10²CFU/g to 4.70±4.67×10³CFU/g. Query sequences of Potential Phenanthrene utilizing fungi all showed 100% relatedness to Aspergillus flavus OR569681, Penicillium citrinum OR237252 and Aspergillus fumigatus OR095908. The query sequences were assigned the Accession number PV642586, PV642585 and PV642584 respectively. These potential phenanthrene utilizing fungi can be harnessed as inoculum in metabolizing polycyclic aromatic hydrocarbon contaminated environment during mycoremediation.