Bioremediation Effects of Bacillus subtilis and Pseudomonas aeruginosa in Crude Oil Spill Affected Soils in Owaza Community, Abia State, Nigeria

The study analyzed the bioremediation effects of Bacillus subtilis and Pseudomonas aeruginosa in crude oil spill affected soils in Owaza community in Abia State, Nigeria. The point sampling method whereby soil samples were collected at random locations within the crude oil spill affected soils was employed for the study. The biodegradation experiments were carried out for 25 days in a nursery shed under natural environmental conditions. The experiments were carried out in four sets. Each of the sets had a control which was not with Cow dung or bacterial inoculation. The entire experimental setup were done in duplicates so that the collection of the samples will not disturb the degradation. The laboratory experiments involved well-structured series of analysis on the different soil samples inoculated with Bacillus subtilis and Pseudomonas aeruginosa. Descriptive statistics in form of Tables was employed for data presentation while Excel work sheet 2010 was employed for data analysis. Findings of the study revealed that at the end of the 25 days of the experiment, the mean population densities of Bacillus subtilis increased and recorded a total hydrocarbon content reduction of 54.4%. Similarly, the mean population densities of Pseudomonas aeruginosa increased at the end of the 25 days and recorded a total hydrocarbon content reduction of 54.71%. Findings further revealed that the combination of Bacillus subtilis and Pseudomonas aeruginosa significantly increased the population densities of bacteria isolates and recorded a total hydrocarbon contents reduction rates of 69.75%. The study concluded that Bacillus subtilis and Pseudomonas aeruginosa can lead to significant reduction in hydrocarbon contents in crude oil spill affected soils overtime, especially when more days can be deployed for the experiment. The study recommends that research expansion is therefore needed in this area for effective bioremediation techniques in cases of crude oil spill effects on soil quality.