Journal of Bioscience and Biotechnology Discovery

The bacteriological and physicochemical changes of automobile workshop polluted soil in Lokoja, Kogi State, Nigeria, amended with varying concentrations of fish pond sludge (10%, 20% and 40%) was studied for six months. The bacteria population was assessed using serial dilution and plate counts after 24 hours of incubation on nutrient agar. Pure isolates were Gram-stained and subjected to molecular analysis. Physicochemical properties of the soil, such as pH, moisture content, organic carbon, organic matter content, nitrate and phosphate, were analysed using standard procedures. Molecular analysis of the isolates showed the presence of Bacillus cereus, Bacillus subtilis, Corynebacterium xerosis, Lysinbacillus fusiformis, Micrococcus luteus, Paenibacillus polymyxa and Rhodococcus erythropolis. The physicochemical analysis revealed the range of 5.78 ± 0.40- 7.20 ± 0.20 for pH, 6.47±1.03 to 12.72±1.91 % for moisture content, 0.24 ± 0.04 to 0.67 ± 0.17mg/kg for nitrate and 13.25 ± 2.50 to 20.22 ± 3.17mg/kg for phosphate. There were no significant differences in the phosphate level of the soil undergoing bioremediation at 0.05 probability limits. However, significant differences were observed in the pH, moisture content, organic carbon, organic matter content and nitrate concentration of the automobile workshop polluted soil fused with fish pond sludge at 95% confidence interval. The findings from this study revealed that automobile workshop soil treated with 40% sludge (M+40%) had higher bacterial population and rate of utilisation of organic carbon, organic matter content, nitrate and phosphate compared to other treatments. This study recommends the use of organic waste in the bioremediation of automobile workshop-polluted soil.