Hydrocarbon Degradation Potential of Heterotrophic Bacteria Isolated from Oil Polluted Sites in Sakpenwa Community in Rivers State

Abstract

In this study, hydrocarbon degradation potentials of heterotrophic bacteria isolated from oil-polluted soil were examined. Samples were collected from Sakpenwa, an oil producing community in Tai LGA of Rivers State, Nigeria and analyzed for physicochemical and microbiological properties using standard techniques. Hydrocarbon utilizing bacteria (HUB) were isolated by vapour phase transfer method using mineral salt medium. The biodegradation study was carried out on a standard laboratory shaker for 30 days in Bushnell -Haas agar supplemented with 5% of crude oil. Fifteen (15) bacterial isolates were screened for hydrocarbon degradation potentials of which five isolates exhibited high hydrocarbon degradability.  The following parameters were monitored using each of the five isolates and a consortium during the biodegradation study: Colour change, Optical density (OD), pH, Total Petroleum Hydrocarbon (TPH), Total Hydrocarbon Contents (THC) and Total Cuturable Heterotrophic Bacterial Counts (TCHBC). The mean TCHBC ranged from 1.65×107 to 2.27×108cfu/ml while the mean Total Culturable Hydrocarbon Utilizing Bacterial Counts ranged from 1.09×104 to 3.9×105. The optical density varied from 0.09±0.02 - 2.57±0.00 and pH ranged from 2.98±0.09 - 6.98±0.09. The optical density varied to .09±0.02 - 2.57±0.00 and pH ranged from 2.98±0.09 -0.98±0.09. The gravimetric analysis showed that Bacillus sp., Pseudomonas sp. Alcaligenes sp. and Acinetobacter sp. were able to degrade 96.90%, 99.60%, 99.20% and 99.70% of the hydrocarbons respectively. This study demonstrated that indigenous bacterial species were highly efficient in the biodegradation of petroleum hydrocarbons.