ORIGINAL PAPERMicrobial degradation of petroleum hydrocarbons in a pollutedtropical streamSunday A. Adebusoye Æ Matthew O. Ilori ÆOlukayode O. Amund Æ Olakunle D. Teniola ÆS. O. OlatopeReceived: 2 August 2006/Accepted: 8 December 2006/Published online: 24 January 2007? Springer Science+Business Media B.V. 2007SummaryCrude oil degradation was observed inwater samples from three sites along the course of apolluted stream in Lagos, Nigeria. Consistent increaseand decrease in the total viable counts (TVCs) ofindigenous organisms occurred in the test and controlexperiments, respectively. Enrichments of the watersamples with crude oil resulted in the isolation of ninebacteria belonging to seven genera. A mixed culturewas developed from the assemblage of the nine species.The defined microbial consortium utilized a wide rangeof pure HCs including cycloalkane and aromatic HCs.Utilization of crude oil and petroleum cuts, i.e., kero-sene and diesel resulted in an increase in TVC (till day10) concomitant with decreases in pH and residual oilconcentration. Crude oil, diesel and kerosene weredegraded by 88, 85 and 78%, respectively, in 14 days.Substrate uptake studies with axenic cultures showedthat growth was not sustainable on either cyclohexaneor aromatics while degradation of the petroleum frac-tions fell below 67% in spite of extended incubationperiod (20 day). From the GC analysis of recoveredoil, while reductions in peaks of n-alkane fractions andinbiomarkersnamelyn-C17/pristaneandn-C18/phytane ratios were observed in culture fluids of purestrains, complete removal of all the HC components ofkerosene, diesel and crude oil including the isoprenoidswas obtained with the consortium within 14 days.KeywordsBacteria ? Degradation ? Hydrocarbons ?Phytane ? Pristane ? Residual oilIntroductionContinual crude oil spills in the Niger Delta area ofNigeria due to pipeline bursting and due to oil tankeraccidents and similar occurrences elsewhere havedrawn attention to the problem of petroleum hydro-carbon (PHC) contamination in the environment.Whatever the origin of contamination, some petroleumor decomposition products may reach groundwaterreserves, lakes or water courses providing water fordomestic and industrial use. Apart from possible haz-ards to health such as liver damage and skin problems(Okonkwo 1984), such contamination is objectionablebecause of the very low concentration at which PHCsand associated materials can be detected by their smelland taste (Anyaegbu 1987; Nwankwo and Irrechukwu1987). This problem is most serious in areas which relyon groundwater and rivers as major sources of drinkingwater; as constantly experienced in Lagos and theNiger Delta areas of Nigeria. The pollutant may alsoinhibit some microbial communities that are importantin some biogeochemical cycles of that ecosystem andthis affects the productivity of such ecosystems(Rhodes and Hendricks 1990).The present-day methods of ridding the environ-ment of spilled oil, most especially in Nigeria includeS. A. Adebusoye (&) ? M. O. Ilori ?O. O. AmundFaculty of Science, Department of Botany andMicrobiology, University of Lagos, Akoka, Yaba, Lagos,Nigeriae-mail: sadebusoye@yahoo.comO. D. Teniola ? S. O. OlatopeBiotechnology Division, Federal Institute of IndustrialResearch, Oshodi, Lagos, NigeriaO. D. Teniolae-mail: olakunleteniola@yahoo.com123World J Microbiol Biotechnol (2007) 23:1149–1159DOI 10.1007/s11274-007-9345-3
