Culture-Dependent and Metagenomic Profiling of Eukaryal Diversity in Petroleum Hydrocarbon-Polluted Soil from B-Dere, Gokana, Rivers State, Nigeria

Abstract

B-Dere is one of the communities in Ogoniland and a major oil producing area in Rivers State where oil exploration and production activities commenced 50 years ago and is now characterized by oil fields and installations that have remained dormant for several decades. Past spills, lack of maintenance, oil trapping and damage to oil infrastructures have been common sight in this region and the environment has been without remediation over the years. B-Dere community has suffered surface water pollution throughout its creeks with massive hydrocarbons for years without remediation. The aim of this study was to determine the Culture- dependent and Metagenomic studies of fungal diversity in petroleum polluted soils in B-Dere community in Gokana LGA of Rivers State, Nigeria. This is to profile fungal communities through next-generation techniques by shotgun sequencing of total DNA isolates directly from the oil polluted environment. Soil samples were collected aseptically with hand auger at a depths of 0-15 and 15-30 cm and made up to a composite sample and transported to the laboratory for analysis using standard microbiological methods for culture- dependent analysis while the Metagenomic studies was carried out at the Microbial Insights, Incorporated; United State of America. In this study next-generation sequencing techniques by shotgun sequencing of total DNA methods were used for identification of fungal isolates from the crude oil polluted soils in B-Dere. Deoxyribonucleic acid (DNA) extraction from crude oil polluted soil samples was performed using ZymoBiomics DNA extraction kits (Zymo Research, Inc; USA). DNA sequencing was performed by the next generation sequencing technique to determine the nucleotide sequence of all eukaryal community structure present in the polluted soil sample using ITS region. Results of the culture-dependent technique showed that only two fungal genera namely Penicillium sp and Aspergillus sp were isolated and identified while the soil was mainly dominated by the genera Penicillium (73.33%), followed by the Rhodotorula (6.54%), Dactylellina(5.09%), Kalmanozyma(2.56%), Fereydounia(1.89%), Xerochrysium(1.36%), Arthrobotrys (1.14%) and Diutina (0.77%) by the metagenomic analysis. However the three major groups were classified as Ascomycota, Basidiomycota and Mucoromycota with Ascomycota having the highest taxonomic reads of 86.76%. However, a total of 60 eukaryal species were identified, in the metagenomic study. In conclusion, these fungal strains can be used in bioremediation process and oil pollution reduction in soil ecosystems because of their high activity in aliphatic hydrocarbon degradation and cell surface hydrophobicity. The next-generation techniques by shotgun sequencing assays appear to be suitable alternatives for rapid identification of the above mentioned fungal isolates.