Biodegradation of natural bitumen by Providencia stuartii isolated from heavy oil contaminated soil

Abundance and availability of unconventional petroleum has led to intensified exploitation and exploration of the bitumen reserves. This has however led to environmental pollution. This study investigated the ability of Providencia stuartii isolated from heavy oil polluted soil to degrade natural bitumen. Temperature, pH and incubation period were independent variables used for optimization of degradation while optical density was used as dependent variable. Optical density was measured using a UV-Vis spectrophotometer. Residual bitumen/degradation products were analyzed using gas chromatography- mass spectrometry (GC-MS). Optical densities obtained ranged from 0.002 to 0.408. Optimum optical density of 0.408 was obtained at 40 oC and pH 7 after 13 days of incubation. There were significant changes in the composition of bitumen after analysis with GC-MS with detection of new compounds due to degradation. The GC-MS results showed the presence of some degradation products such as benzene (1-butylhexyl), benzene (1-propylheptyl) and 23, 28-bisnor-17.β.(h)-hopane. This study revealed the excellent ability of P. stuartii in degrading bitumen contaminated environment.