Isolation and Characterization of Hydrocarbon-utilizing Bacteria from Petroleum Sludge Samples obtained from Crude Oil Processing Facility in Nigeria

The isolation and characterization of hydrocarbon-utilizing bacteria from petroleum oily sludge collected from crude oil processing plant in Rivers State, Nigeria was carried out. Microbiological analysis of the sludge sample showed that the microbial load consisted average of 2.5 x 106 cfu/g total heterotrophic bacterial (THB) count, while the hydrocarbon utilizing bacterial (HUB) count was average of 2.0 x 103 cfu/g. Phenotypic characteristics and phylogenetic analysis of the 16S rRNA gene sequence of the isolates revealed that they were related to members of the species Klebsiella pneumonia, Klebsiella oxytoca and Alcaligenes faecalis. The 16S rRNA of the isolates showed percentage similarities to the type strains (99% sequence similarities) of the following; Klebsiella pneumonia strain B21 (gi: 922317936), Klebsella pneumonia strain ICB-C183 (gi: 908478837), Klebsella oxytoca strain BCNAI (gi: 846993354), Klebsella oxytoca strain BC4 (gi: 884060138), Alcaligenes faecalis strain IOU PMR (gi: 686028963) and Alcaligenes faecalis strain AQ-I (gi: 816845513). Of the six hydrocarbon utilizing bacteria identified, 4(67%) were Klebsiella species while 2(33%) were identified as Alcaligenes sp of different strains. The result suggest that these isolated organisms from the petroleum sludge can be explored and used to promote environmentally friendly technology clean-up of petroleum hydrocarbon polluted sites in the Niger Delta region of Nigeria.Keywords: Hydrocarbon -utilizing bacteria, Petroleum sludge, 16S rRNA, Phylogenetic, Gene sequence