Aerobic degradation of a crude oil (sample P1), collected from a deep water reservoir from the Pampo Sul Field (Campos Basin, RJ) at 82 °C and 2405-2588 m, by indigenous bacteria in the oil and formation water was monitored for 60 days. Degradation parameters, measured using gas chromatography-mass spectrometry (GC-MS) of the crude oil degraded in the laboratory for periods of 0, 30, 50 and 60 days, were compared with those of a naturally biodegraded oil (sample P2). The analyses revealed that the n-alkanes were totally depleted by the 60th day when the crude oil (P1, degradation level 2) was transformed into petroleum of biodegradation level 6 (P2). © 2008 Elsevier Ltd. All rights reserved.39812041209Bicalho, B., Chen, L.S., Grognux, J., Reymond, J.L., Marsaioli, A.J., Studies on whole cell fluorescence-based screening for epoxide hydrolases and Baeyer-Villiger monoxygenases (2004) Journal of the Brazilian Chemical Society, 15, pp. 911-916Bost, F.D., Frontera-Suau, R., McDonald, T.J., Peters, K.E., Morris, P.J., Aerobic biodegradation of hopanes and norhopanes in Venezuelan crude oils (2001) Organic Geochemistry, 32, pp. 105-114Brooks, P.W., Fower, M.G., MacQueen, R.W., Biological marker and conventional organic geochemistry of oils sands/heavy oils, Western Canada Basin (1988) Organic Geochemistry, 12, pp. 519-538Chosson, P., Connan, J., Dessort, D., Lanau, C., In vitro biodegradation of steranes and terpanes: a clue to understanding geological situations (1992) Biological Markers in Sediments and Petroleum, pp. 320-349. , Moldowan J.M., Albrecht P., and Philp R.P. (Eds), Prentice HallCoates, J.D., Woodward, J., Allen, J., Philip, P., Lovley, D.R., Anaerobic degradation of polycyclic aromatic hydrocarbons and alkanes in petroleum-contaminated marine harbor sediments (1997) Applied Environmental Microbiology, 63, pp. 3589-3593Domingues, M.R., Vazoller, R.F., Varesche, M.B., Araújo, J.C., Evaluation of thermophilic anaerobic microbial consortia using fluorescence in situ hybridization (FISH) (2002) Water Science and Technology, 45, pp. 27-33Dubourguier, H.C., Buisson, M.N., Tissier, J.P., Prensier, G., Albagnac, G., 1987. Microbiology and technology. In: Proceedings of the GASTMAR - Workshop Pudoc, Netherlands. pp. 78-86Evans, C.R., Rogers, M.A., Bailey, N.J.L., Evolution and alteration of petroleum in Western Canada (1971) Chemical Geology, 8, pp. 147-170Ghazali, F.M., Rahman, R.N.Z.A., Salleh, A.B., Basri, M., Biodegradation of hydrocarbons in soil by microbial consortium (2004) International Biodeterioration and Biodegradation, 54, pp. 61-67Grabowski, A., Blanchet, D., Jeanthon, C., Characterization of long-chain fatty-acid-degrading syntrophic associations from a biodegraded oil reservoir (2005) Research in Microbiology, 156, pp. 814-821Guardado, L.R., Gamboa, L.A.P., Lucchesi, C.F., 1989. Petroleum geology of the Campos Basin, Brazil, a model for a producing Atlantic type basin. In: Edwards, J.D., Santogrossi, P.A. (Eds.), Divergent/Passive Margin Basins. American Association of Petroleum Geologists Memoir 46. pp. 3-79Head, I.M., Martin, J.D., Larter, S.R., Biological activity in the deep subsurface and the origin of heavy oil (2003) Nature, 426, pp. 344-352Jahnert, R., França, A., Trindade, L.A.F., Quintaes, C., Santos, P., Pessoa, J., Bedregal, R.P., 1998. The petroleum system of Campos Basin. In: BGPAAPG International Conference and Exhibition, November 8-11, Rio de Janeiro, Brasil. Extended abstracts volume, 600-601Jones, D.M., Head, I.M., Gray, N.D., Adams, J.J., Rowan, A.K., Aitken, C.M., Bennett, B., Larter, S.R., Crude-oil biodegradation via methanogenesis in subsurface petroleum reservoirs (2008) Nature Letters, 451, pp. 176-181Korda, A., Santas, P., Tenente, A., Santas, R., Petroleum hydrocarbon bioremediation: sampling and analytical techniques, in situ treatments and commercial microorganisms currently used (1997) Applied Environmental Microbiology, 48, pp. 677-686Magot, M., Ollivier, B., Patel, B.K.C., Microbiology of petroleum reservoirs (2000) Antonie Van Leeuwenhoek, 77, pp. 103-116Mohiak, W.U., Mello, M.R., Karner, G.D., Dewey, J.F., Maxwell, J.R., Structural and stratigraphic evolution of the Campos Basin, offshore Brazil. Extensional tectonics and stratigraphy of North Atlantic margins: Analogs (1989) American Association of Petroleum Geologists Memoir, 46, pp. 577-598Moldowan, J.M., McCaffrey, M.A., A novel microbial hydrocarbon degradation pathway revealed by hopane demethylation in a petroleum reservoir (1995) Geochimica et Cosmochimica Acta, 59, pp. 1891-1894Peters, K.E., Walters, C.C., Moldowan, J.M., (2005) The Biomarker Guide: Biomarkers and Isotopes in Petroleum Exploration and Earth History. second ed., 2. , Cambridge University Press, New YorkPeters, K.E., Moldowan, J.M., Effects of source, thermal maturity, and biodegradation on the distribution and isomerization of homohopanes in petroleum (1991) Organic Geochemistry, 17, pp. 47-61Ponte, F.C., Asmus, H.E., Geological framework of the Brazilian continental margin (1978) Geologische Rundschau, 67, pp. 201-235Rangel, H.D., Martins, F.A.L., Esteves, F.R., Feijó, F.J., Bacia de Campos (1994) Boletim de Geociências da Petrobrás, 8, pp. 203-217Roling, W.F.M., Head, I.M., Larter, S.R., The microbiology of hydrocarbon degradation in subsurface petroleum reservoirs: perspectives and prospects (2003) Research in Microbiology, 154, pp. 321-328Seifert, W.K., Moldowan, J.M., The effect of biodegradation on steranes and terpanes in crude oils (1979) Geochimica et Cosmochimica Acta, 43, pp. 111-126van Hamme, J.D., Singh, A., Ward, O.P., Recent advances in petroleum microbiology (2003) Microbiology and Molecular Biology Reviews, 67, pp. 503-549Vazoller, R.F., Microbial aspects of thermophilic anaerobic biodigestion of vinasse (1997) Novel Trends in Biological Wastewater, Progress in Microbial Ecology, pp. 527-532. , ISMEWatson, J.S., Jones, D.M., Swannell, R.P.J., Duin, A.C.T., Formation of carboxylic acids during aerobic biodegradation of crude oil and evidence of microbial oxidation of hopanes (2002) Organic Geochemistry, 33, pp. 1153-1169Xu, J., Trimble, J.J., Steinberg, L., Logan, B.E., Chlorate and nitrate reduction pathways are separately induced in the perchlorate-respiring bacterium Dechlorosoma sp. KJ and the chlorate-respiring bacterium Pseudomonas sp. PDA (2004) Water Research, 38, pp. 673-680Zinder, S.H., Cardwell, S.C., Anguish, T., Lee, M., Koch, M., Methanogenesis in a thermophilic anaerobic digester: Methanotrix sp. as an important aceticlastic methanogen (1984) Applied Environmental Microbiology, 47, pp. 796-807