In vitro degradation of bitumen by microorganisms isolated around bitumen deposit at Agbabu was investigated. The microorganisms were isolated from soil sample collected around bitumen deposit and bitumen itself. The ability of individual isolates to utilize bitumen as sole carbon source in mineral salt medium was investigated. The results showed a decrease in the pH of the medium with an increase in the bacteria cell densities within the period of incubation, thereby confirming activities of the isolates in the medium. Bacillus subtilis (29.15%) caused highest weight loss from the bitumen, while Pseudomonas aeruginosa (12.03%) caused the least among the bacteria isolate. Other bacteria isolated were Acinetobacter sp. and Staphylococcus aureus. Both also caused weight loss from the bitumen. For moulds, Arthrobotrys oligospora caused higher percentage weight loss (19.13%), than Aspergillus niger in 28 days of incubation. By the 56 days of incubation, Bacillus subtilis was still responsible for highest weight loss (49.50%), while Pseudomonas aeruginosa exhibited the lowest percentage (23.17%). For the moulds, Arthrobotrys oligospora still had the higher weight loss (42.83%) while Aspergillus niger had 37.33%. Thus, this established that the microorganisms isolated from the soil around the Agbabu bitumen and the bitumen itself could degrade bitumen from tar sand, hence their potential usefulness in remediation of bitumen polluted environment when the exploitation of the resource commenced.
Key words: Bitumen; Bacteria; Mould; Hydrocarbon
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