Isolation and identification of bacteria from engine oil polluted soil from mechanic workshops in Okija Town

Abstract

This research was conducted for the isolation and identification of bacteria from engine oil polluted soil from mechanic workshops in Okija village. Two different mechanic workshops within Okija were selected and soil samples were collected differently based on top soil and depth soil from each site. Then 0.1ml was taken from the dilution 10-3 to 10-6 diluents and inoculated into a Bushnell Haas agar (containing: (g/l) 0.2, MgSO4; 0.02, CaCl2; 1.0, KH2PO4; 1.0, K2HPO4; 1.0, NH4NO3; 0.05, FeCl3; 20.0, Agar and 5ml of fresh engine oil as sole carbon source) and was incubated at 370C for 5 -7 days. Spread plate method involving the use of serial dilutions was employed for the isolation of bacteria. The culture was examined for bacterial growth and subsequently cultured the specific bacteria growth on nutrient agar plates with 2ml of fresh engine oil for 24 hours to determine engine oil degradability by the isolated bacteria. The numbers of viable bacterial count were 20, 26, 18 and 28 as expressed in colony forming units per milliliter (cfu/ml). The bacterial count was furthermore expressed in percentage per the dilution factor 10-3; S1Top, S1Depth, S2Top and S2Depth were 21.74%, 28.26%, 19.56% and 30.44% respectively. The bacteria species isolated were Serratia, Micrococcus, Pseudomonas and Bacillus species. Bacillus was the most dominant. There was presence and activity of bacteria species in the depth soil than top soil. The bacterial species isolated were able to degrade fresh engine oil especially Bacillus species. From, the data obtained it was found that depth soil has more presence and activity of bacterial species because there is less disturbance in the depth soil than top soil. Bacillus species and Pseudomonas species are most adapted to conditions present in soils polluted with used engine oil and hence could be exploited in bioremediation activities in cases of accidental oil spillage.