Investigation of crude oil anaerobic biodegradation in microcosms by microbiota from Brazilian oil reservoir samples

Abstract

Most of the world petroleum reserves are biodegraded and strong indirect evidences suggest that anaerobic microorganisms, mainly sulfate reducers and methanogens are responsible for biodegradation in oil fields. Therefore, anaerobiosis is considered a dominant process for in-reservoir hydrocarbon degradation and for other different oil-polluted environments. Several laboratory enrichments have been performed to study microbial communities and the extent of hydrocarbon degradation under anaerobic conditions. However, little information has been available on oil samples from petroleum reservoirs and even less about the effect of some physicochemical characteristics of the reservoir rock on the crude oil biodegradation rate and the microbial mechanisms employed for in-reservoir hydrocarbon degradation. This proposal aims to investigate the effect of a range of physicochemical conditions on petroleum biodegradation in anaerobic microcosms, as well as to monitor the functional and phylogenetic dynamics of the microbial community during oil biodegradation. The assay will be harnessed with molecular tools which will allow us to describe the most probable mechanisms involved with the hydrocarbon degradation. Results will certainly contribute to the clarification not only the physico-chemical factors governing the degradation of oil in Brazilian petroleum reservoirs, but also, the microorganisms and metabolic processes involved. This experience will be extremely enriching for our research group, since it will enable the learning of techniques to work with oil degradation under methanogenic and sulphate-reducing (anaerobic) conditions for future implementation in our laboratory. (AU)