Comparative study on the rate of biodegradation of crude oil by bacteria and fungi isolates was carried out using growth and biodegradation indices in an oil supplemented mineral salt medium. The bacterial genera that were isolated from oil-polluted sample from location 1 of Shell Petroleum Development Company (SPDC), at Ukwugba Village in Egbema include: Bacillus, Pseudomonas, Micrococcus and Acinetobacter, while the genera of fungi include: Trichosporon, Aspergillus and Mucor. Bacillus sp. and Trichosporon sp. were used for the comparative study. The microbial growth was monitored by UV spectrophotometer (Astell UV- Vis Grating, 752W) at absorbance (OD520nm) while degradation was monitored by gas chromatography (model HP 5890 series II; GC Injection and detector temperature: 65°C and 275°C; Column: Capillary Column (HP5) -30m length, 0.32mm internal diameter, 0.25 µm film diameter; and Detector: Flame Ionization Detector) . An increased growth from 0.17 - 0.53% was recorded for Bacillus sp. and 0.11 – 0.45% for Trichosporon sp. The degradation analysis showed quantitative reductions in the total petroleum hydrocarbons (TPHs) which ranged from 12, 405 to 122mg/1 and 12, 405 to 712mg/1 for Bacillus sp. and Trichosporon sp. respectively during the 21 days incubation period. Statistically, significant differences were detected in the growth and degradation parameters measured between Bacillus sp. and Trichosporon sp. Observations of the study conclude that both Bacillus and Trichosporon species have potentials for degradation of Bonny light crude oil, however, comparatively Bacillus species are better utilizers and degraders of Bonny light crude oil than Trichosporon species.
