Bioremediation of soil polluted with spent lubricating oil using bacteria isolated from soil in Abuja Metropolis

Background: The presence of spent hydrocarbon in soil is a serious problem to the environment hence study on bioremediation of soil polluted with auto-mechanic oil in Abuja Metropolis was carried out. Methods: A total of twenty (20) soil samples were collected, bacteria were isolated from the contaminated soil and identified using standard microbiological methods. The spent hydrocarbon utilization was determined using Atomic Adsorption UV Spectrometer. Results: The total viable count of the bacteria was 1.07 x 106 from Apo Mechanic village, 1.10 x 106 from Utako Mechanic workshops, 0.40 x 106 from Gwarinpa Mechanic workshops and 2.04 x 106 from Area one Mechanic workshops. The percentage occurrence of bacteria from Apo Mechanic village was Enterobacter species 40.0%, Pseudomonas synxantha 60.0%, Bacillus zanthoxyli 40.0% and Proteus vulgaris 20.0%. Utako Mechanic workshops were Enterobacter kobei 20.0%, Pseudomonas synxantha 40.0%, Bacillus zanthoxyli 20.0% and Proteus vulgaris 40.0%. Gwarinpa Mechanic workshops were Pseudomonas synxantha 20.0% and Bacillus zanthoxyli 20.0%. Area one Mechanic workshops were Enterobacter kobei 40.0% and Pseudomonas synxantha 40.0%. The effect of days on utilization of spent hydrocarbon showed that Pseudomonas synxantha had highest utilized of spent hydrocarbon 19.55mg/ml after 21 days. The effect of pH on utilization of spent hydrocarbon show that at pH 7.5, Enterobacter kobei, Bacillus zanthoxyli and Proteus vulgaris species had the highest utilization of spent hydrocarbon ranging from 5 9.33mg/ml-12.70mg/ml. Effect of temperature on utilization of spent hydrocarbon showed that at 28OC Enterobacter kobei, Pseudomonas synxantha, Bacillus zanthxyli and Proteus vulgaris had the highest utilization of spent hydrocarbon ranging from 5.51mg/ml- 11.11mg/ml. the bacteria isolated from the contaminated soil have the ability to utilized the hydrocarbon if the soil is amended with some mineral element as shown in this study. Conclusion: In conclusion bacteria isolates effectively bioremediated the automechanic oil polluted soil with a reduction of hydrocarbon pollutants.