Abstract

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Soil and sediment samples collected from crude oil impacted sites at Ogale-Eleme, Rivers State, and five water samples from effluent discharge points at five different flow stations in Delta State, all in the Niger Delta area of Nigeria respectively were analyzed for the presence of hydrocarbon utilizing bacteria using Bushnell-Haas agar, followed by dioxygenase screening. A total of sixty bacterial species under eleven genera were isolated, characterized and identified as Acinetobacter, Alcaligenes, Bacillus, Edwardsiella, Entervbacter, Flavobacterium, Klebsiella, Micrococcus, Proteus, Pseudomonas and Staphylococcus. Out of the sixty bacteria characterized, only four isolates from the water sample obtained from Ahia flow station in Delta State and sediment sample E identified as Pseudomonas spp. were found to possess the enzyme dioxygenase. This was detected using indigo production by putative hydrocarbon utilizing bacteria. Indigo is produced as an intermediate in indole metabolism by dioxygenases via the meta-cleavage pathway. Bacteria possessing dioxygenases reduced indole to indigo while colonies of such isolates turned navy blue. The findings demonstrate that autochthonous hydrocarbon utilizing bacteria associated with crude oil polluted sites in Niger Delta may probably possess the natural propensity to degrade aromatic hydrocarbons in crude oil.

Keywords: Dioxygenases, indole, meta-cleavage pathway, hydrocarbon utilizing bacteria, Niger Delta.