title: Nitrate-Mediated Microbially Enhanced Oil Recovery (N-MEOR) from model upflow bioreactors.
abstract: Microbially Enhanced Oil Recovery (MEOR) can enhance oil production with less energy input and less costs than other technologies. The present study used different aqueous electron donors (acetate, glucose, molasses) and an aqueous electron acceptor (nitrate) to stimulate growth of heterotrophic nitrate reducing bacteria (hNRB) to improve production of oil. Initial flooding of columns containing heavy oil (viscosity of 3400cP at 20°C) with CSBK (Coleville synthetic brine medium) produced 0.5 pore volume (PV) of oil. Bioreactors were then inoculated with hNRB with 5.8g/L of molasses and 0, 10, 20, 40, 60 or 80mM nitrate, as well as with 17mM glucose or 57mM acetate and 80mM nitrate. During incubations no oil was produced in the bioreactors that received 5.8g/L of molasses and 0, 10, 20, 40 or 60mM nitrate. However, the bioreactors injected with 5.8g/L of molasses, 17mM glucose or 57mM acetate and 80mM nitrate produced 13.9, 11.3±3.1 and 17.8±6.6% of residual oil, respectively. The significant production of oil from these bioreactors may be caused by N2-CO2gas production. Following continued injection with CSBK without nitrate, subsequent elution of significant residual oil (5-30%) was observed. These results also indicate possible involvement of fermentation products (organic acids, alcohols) to enhance heavy oil recovery.
authors.affiliation: Petroleum Microbiology Research Group, Department of Biological Sciences, University of Calgary, Calgary, Alberta T2N 1N4, Canada. Electronic address: fgassara@ucalgary.ca.
authors.forename: Fatma
authors.initials: F
authors.lastname: Gassara
authors.affiliation: Petroleum Microbiology Research Group, Department of Biological Sciences, University of Calgary, Calgary, Alberta T2N 1N4, Canada. Electronic address: nksuri@ucalgary.ca.
authors.forename: Navreet
authors.initials: N
authors.lastname: Suri
authors.affiliation: Petroleum Microbiology Research Group, Department of Biological Sciences, University of Calgary, Calgary, Alberta T2N 1N4, Canada. Electronic address: voordouw@ucalgary.ca.
authors.forename: Gerrit
authors.initials: G
authors.lastname: Voordouw
mesh_terms: D001419:Bacteria; D019149:Bioreactors; D004583:Electrons; D004655:Emulsions; D052836:Heterotrophic Processes; D007220:Industrial Waste; D008965:Molasses / Q000382:microbiology; D009566:Nitrates / Q000378:metabolism*; D010084:Oxidation-Reduction; D010578:Petroleum / Q000378:metabolism*; D013500:Surface Tension; D014783:Viscosity
chemical_list: D004655:Emulsions; D007220:Industrial Waste; D009566:Nitrates; D010578:Petroleum
keywords: Glucose; Heterotrophic nitrate reducing bacteria; Microbially Enhanced Oil Recovery; Molasses; acetate