Compositions of microbial communities associated with oil and water in a mesothermic oil field

Abstract

Samples of produced water and oil obtained from the Enermark field (near Medicine Hat, Alberta, Canada) were separated into oil and aqueous phases first gravitationally and then through centrifugation at 20°C in an atmosphere of 90% N(2) and 10% CO(2). Biomass that remained associated with oil after gravitational separation (1×g) was dislodged by centrifugation at 25,000×g. DNA was isolated from the aqueous and oil-associated biomass fractions and subjected to polymerase chain reaction amplification with primers targeting bacterial and archaeal 16S rRNA genes. DNA pyrosequencing and bioinformatics tools were used to characterize the resulting 16S rRNA gene amplicons. The oil-associated microbial community was less diverse than that of the aqueous phase and had consistently higher representation of hydrogenotrophs (methanogens of the genera Methanolobus and Methanobacterium and acetogens of the genus Acetobacterium), indicating the oil phase to be a primary source of hydrogen. Many known hydrocarbon degraders were also found to be oil-attached, e.g. representatives of the gammaproteobacterial genus Thalassolituus, the actinobacterial genus Rhodococcus and the alphaproteobacterial genera Sphingomonas, Brevundimonas and Stappia. In contrast, all eight representatives of genera of the Deltaproteobacteria identified were found to be associated with the aqueous phase, likely because their preferred growth substrates are mostly water-soluble. Hence, oil attachment was seen for genera acting on substrates found primarily in the oil phase.

Acetate Production from Oil under Sulfate-Reducing Conditions in Bioreactors Injected with Sulfate and Nitrate

“…Other bacteria that satisfy this criterion are Acetobacterium, Acidaminobacter, Propionibacteriaceae, Synergistetes/Thermanaerovibrio, Kosmotoga, Fusibacter, Aquabacterium, Sediminibacterium, and many others. Several of these have been found in communities degrading xenobiotic compounds or in communities derived from oil, gas, or coal fields (47)(48)(49)(50)(51). Our knowledge of anaerobic, syntrophic hydrocarbon degradation is still rudimentary, making it impossible to implicate taxa on the basis of 16S rRNA pyrosequencing surveys.…”

Anaerobic Microbial Diversity and Abundance in Xinjiang low-Temperature Water- Flooding Petroleum Reservoir

“…Additionally, mesophilic fermentative halophilic Spirochaeta smaragdinae was isolated from an African oil field [33]. Moreover, Spirochaetes were obtained in a low-salinity non-flooded 20 °C oil reservoir in water-flooding Enermark oil fields and in a non-flooded high-temperature oil reservoir [14,34,35].…”

Subsurface Petroleum Microbiology

“…The oil sand deposits comprise of at least 85 % of the total immobile bitumen in place in the world and are an important source of economically recoverable oil. Oil sands are formed through the microbial biodegradation of light oils over millions of years, resulting in increased viscosity, sulfur, resin, asphaltenes, and metal content (Kryachko et al 2012). There are three major oil sand deposits in the WCSB with exploitable bitumen reserves: Athabasca (~75,000 km 2 ; 0-500 m below ground surface), Cold Lake (~22,000 km 2 ; 985-1,970 m below ground surface), and Peace River (8,000 km 2 ; 550-700 m below ground surface).…”

“…The products of nitrate reduction include nitrite, which can inhibit sulfate reducers, but which also serves as an electron acceptor for the oxidation of organic or reduced sulfur-containing electron donors. Oil field microbial community composition, and their changes in response to the use of chemical addition, has been studied through culturing, by denaturing gradient gel electrophoresis, by sequencing of clone libraries, and, more recently, using metagenomic techniques (Bødtker et al 2009;Gittel et al 2009;van der Kraan et al 2010;Kotlar et al 2011;Ren et al 2011;Stevenson et al 2011;Hubert et al 2012;Kryachko et al 2012). Table 9.1 shows some of the microbial species isolated from petroleum oilfields (Magot et al 2000;Tang et al 2009;Ollivier and Alazard 2010).…”