Isolation, Screening and Identification of Biosurfactant-producing Bacteria from Hydrocarbon-polluted and Pristine Soils within Ogoniland, Nigeria

Aim: This study investigated the production of biosurfactant from bacteria isolated from hydrocarbon-polluted and pristine soils within Ogoniland in the Niger Delta region of Nigeria.

Methods: Baseline physicochemical parameters of the soil (total petroleum hydrocarbon (TPH), the nature of the soils, pH and temperature) were examined. The biosurfactant-producing bacteria were screened using emulsification assay, emulsification index (E24), lipase activity, haemolytic assay, oil spreading and tilted glass slide. The biosurfactant-producing bacteria were characterized by phenotypic, biochemical and molecular means.

Results: The respective baseline TPH, temperature and pH were 9,419 mg/kg, 28.5±0.4°C and 5.7±0.1 for hydrocarbon- polluted soil and 1.28 mg/kg, 27.5±0.3°C and 3.7±0.1 for pristine soil. Meanwhile, the respective soil types for the polluted and pristine were humus soil mixed with oil and ordinary humus. Six isolates (IVN-02, IVN-45, IVN-51, IVN-61, IVN-67 and IVN-74) out of forty one (41) distributed within the two different soil samples were found to produce biosurfactant. Phylogenetic analysis based on the 16S rRNA genes classified the six isolates as Pseudomonas sp. IVN02, Alcaligenes faecalis IVN45, Klebsiella pneumoniae IVN51, A. faecalis IVN61, Enterobacter sacchari IVN67 and P. aeruginosa IVN74 respectively. The isolates have been deposited at the GenBank under the accession numbers KT254065, KT254066, KT254060, KT254063, KT254061 and KT254059.

Conclusion: This study demonstrated efficient biosurfactant production from bacterial isolate from hydrocarbon-polluted and pristine soils in Ogoniland within the Niger Delta region of Nigeria. The ability of the bacterial isolates from this region to produce biosurfactant is important considering the level of pollution in Ogoniland and the need to use indigenous and ecologically friendly products in the remediation process.