An investigation on the ability of microorganisms to utilize phenol as a carbon source for growth was carried out using standard microbiological techniques. The sample used in this investigation was a petroleum polluted soil which was serially diluted and plated out on sabouraud dextrose, nutrient and cetrimide agar. The Total Heterotrophic bacteria and fungi that grew on petroleum polluted soil were: Staphylococcus spp, Bacillus spp, Lactobacillus spp, Clostridium spp, Micrococcus spp and Pseudomonas spp for the bacterial species and the fungal species were, Aspergillus niger, Penicillium spp, Rhizopus spp, Aspergillus fumigatus and Trichophyton spp. A control sample was used to check for the occurrence of these organisms found in the polluted soil. The bacterial species isolated were: Staphylococcus spp, Bacillus spp, Lactobacillus spp, Clostridium spp, Micrococcus spp and the fungal species found were; Aspergillus niger, Penicillium spp, Rhizopus spp, Aspergillus fumigatus and Trichophyton spp. This showed that these organisms can exist also in the control sample. These organisms were tested for their ability to utilize phenol as a sole carbon source by spreading 0.1ml of the isolated organism on mineral salt agar, and adding varying concentrations of phenol, 100ppm, 200ppm, 500ppm and 1000ppm as sole carbon source. It was deduced that Staphylococcus spp, Bacillus spp, Pseudomonas spp and Aspergillus niger were the best fitted organisms that utilize phenol. Statistical analysis using ANOVA showed that in terms of phenol concentration, 100ppm, 20pp, 500ppm and 1000ppm; there was a significant difference in the growth rate of the organisms in comparison with the different days (2,3,4,5,6and 7) observed during this study.
