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DEVELOPMENT OF MICROORGANISMS WITH IMPROVED TRANSPORT AND BIOSURFACTANT ACTIVITY FOR ENHANCED OIL RECOVERY

Description: Diverse microorganisms were screened for biosurfactant production and anaerobic growth at elevated salt concentrations to obtain candidates most suitable for microbial oil recovery. Seventy percent of the 205 strains tested, mostly strains of Bacillus mojavensis, Bacillus subtilis, Bacillus licheniformis, and Bacillus sonorensis, produced biosurfactants aerobically and 41% of the strains had biosurfactant activity greater than Bacillus mojavensis JF-2, the current candidate for oil recovery. Biosurfactant activity varied with the percentage of the 3-hydroxy-tetradecanoate isomers in the fatty acid portion of the biosurfactant. Changing the medium composition by incorporation of different precursors of 3-hydroxy tetradecanoate increased the activity of biosurfactant. The surface tension and critical micelle concentration of 15 different, biosurfactant-producing Bacillus strains was determined individually and in combination with other biosurfactants. Some biosurfactant mixtures were found to have synergistic effect on surface tension (e.g. surface tension was lowered from 41 to 31 mN/m in some cases) while others had a synergistic effect on CMD-1 values. We compared the transport abilities of spores from three Bacillus strains using a model porous system to study spore recovery and transport. Sand-packed columns were used to select for spores or cells with the best transport abilities through brine-saturated sand. Spores of Bacillus mojavensis strains JF-2 and ROB-2 and a natural recombinant, strain C-9, transported through sand at very high efficiencies. The earliest cells/spores that emerged from the column were re-grown, allowed to sporulate, and applied to a second column. This procedure greatly enhanced the transport of strain C-9. Spores with enhanced transport abilities can be easily obtained and that the preparation of inocula for use in MEOR is feasible. Tertiary oil recovery experiments showed that 10 to 40 mg/l of JF-2 biosurfactant in the presence of 0.1 mM 2,3-butanediol and 1 g/l of partially hydrolyzed polyacrylamide (PHPA) recovered 10-40% of residual oil from Berea ...
Date: May 31, 2004
Creator: McInerney, M.J.; Youssef, N.; Fincher, T.; Maudgalya, S.K.; Folmsbee, M.J.; Knapp, R. et al.
Partner: UNT Libraries Government Documents Department

DEVELOPMENT OF MICROORGANISMS WITH IMPROVED TRANSPORT AND BIOSURFACTANT ACTIVITY FOR ENHANCED OIL RECOVERY

Description: Biosurfactants enhance hydrocarbon biodegradation by increasing apparent aqueous solubility or affecting the association of the cell with poorly soluble hydrocarbon. Here, we show that a lipopeptide biosurfactant produced by Bacillus mojavensis strain JF-2 mobilized substantial amounts of residual hydrocarbon from sand-packed columns when a viscosifying agent and a low molecular weight alcohol were present. The amount of residual hydrocarbon mobilized depended on the biosurfactant concentration. One pore volume of cell-free culture fluid with 900 mg/l of the biosurfactant, 10 mM 2,3-butanediol and 1000 mg/l of partially hydrolyzed polyacrylamide polymer mobilized 82% of the residual hydrocarbon. Consistent with the high residual oil recoveries, we found that the bio-surfactant lowered the interfacial tension (IFT) between oil and water by nearly 2 orders of magnitude compared to typical IFT values of 28-29 mN/m. Increasing the salinity increased the IFT with or without 2,3-butanediol present. The lowest interfacial tension observed was 0.1 mN/m. The lipopeptide biosurfactant system may be effective in removing hydrocarbon contamination sources in soils and aquifers and for the recovery of entrapped oil from low production oil reservoirs. Previously, we reported that Proteose peptone was necessary for anaerobic growth and biosurfactant production by B. mojavensis JF-2. The data gathered from crude purification of the growth-enhancing factor in Proteose peptone suggested that it consisted of nucleic acids; however, nucleic acid bases, nucleotides or nucleosides did not replace the requirement for Proteose Peptone. Further studies revealed that salmon sperm DNA, herring sperm DNA, Echerichia coli DNA and synthetic DNA replaced the requirement for Proteose peptone. In addition to DNA, amino acids and nitrate were required for anaerobic growth and vitamins further improved growth. We now have a defined medium that can be used to manipulate growth and biosurfactant production. As an initial step in the search for a better biosurfactant-producing microorganism, 157 bacterial ...
Date: June 26, 2003
Creator: McInerney, M.J.; Knapp, R.M.; D.P. Nagle, Jr.; Duncan, Kathleen; Youssef, N.; Folmsbee, M.J. et al.
Partner: UNT Libraries Government Documents Department

Development of an In Situ Biosurfactant Production Technology for Enhanced Oil Recovery

Description: The long-term economic potential for enhanced oil recovery (EOR) is large with more than 300 billion barrels of oil remaining in domestic reservoirs after conventional technologies reach their economic limit. Actual EOR production in the United States has never been very large, less than 10% of the total U. S. production even though a number of economic incentives have been used to stimulate the development and application of EOR processes. The U.S. DOE Reservoir Data Base contains more than 600 reservoirs with over 12 billion barrels of unrecoverable oil that are potential targets for microbially enhanced oil recovery (MEOR). If MEOR could be successfully applied to reduce the residual oil saturation by 10% in a quarter of these reservoirs, more than 300 million barrels of oil could be added to the U.S. oil reserve. This would stimulate oil production from domestic reservoirs and reduce our nation's dependence on foreign imports. Laboratory studies have shown that detergent-like molecules called biosurfactants, which are produced by microorganisms, are very effective in mobilizing entrapped oil from model test systems. The biosurfactants are effective at very low concentrations. Given the promising laboratory results, it is important to determine the efficacy of using biosurfactants in actual field applications. The goal of this project is to move biosurfactant-mediated oil recovery from laboratory investigations to actual field applications. In order to meet this goal, several important questions must be answered. First, it is critical to know whether biosurfactant-producing microbes are present in oil formations. If they are present, then it will be important to know whether a nutrient regime can be devised to stimulate their growth and activity in the reservoir. If biosurfactant producers are not present, then a suitable strain must be obtained that can be injected into oil reservoirs. We were successful in answering all three ...
Date: September 30, 2007
Creator: McInerney, M. J.; Knapp, R. M.; Duncan, Kathleen; Simpson, D. R.; Youssef, N.; Ravi, N. et al.
Partner: UNT Libraries Government Documents Department

Development of Microorganisms with Improved Transport and Biosurfactant Activity for Enhanced Oil Recovery

Description: The project had three objectives: (1) to develop microbial strains with improved biosurfactant properties that use cost-effective nutrients, (2) to obtain biosurfactant strains with improved transport properties through sandstones, and (3) to determine the empirical relationship between surfactant concentration and interfacial tension and whether in situ reactions kinetics and biosurfactant concentration meets appropriate engineering design criteria. Here, we show that a lipopeptide biosurfactant produced by Bacillus mojavensis strain JF-2 mobilized substantial amounts of residual hydrocarbon from sand-packed columns and Berea sandstone cores when a viscosifying agent and a low molecular weight alcohol were present. The amount of residual hydrocarbon mobilized depended on the biosurfactant concentration. Tertiary oil recovery experiments showed that 10 to 40 mg/l of JF-2 biosurfactant in the presence of 0.1 mM 2,3-butanediol and 1 g/l of partially hydrolyzed polyacrylamide (PHPA) recovered 10-40% of residual oil from Berea sandstone cores. Even low biosurfactant concentrations (16 mg/l) mobilized substantial amounts of residual hydrocarbon (29%). The bio-surfactant lowered IFT by nearly 2 orders of magnitude compared to typical IFT values of 28-29 mN/m. Increasing the salinity increased the IFT with or without 2,3-butanediol present. The lowest interfacial tension observed was 0.1 mN/m. A mathematical model that relates oil recovery to biosurfactant concentration was modified to include the stepwise changes in IFT as biosurfactant concentrations changes. This model adequately predicted the experimentally observed changes in IFT as a function of biosurfactant concentration. Theses data show that lipopeptide biosurfactant systems may be effective in removing hydrocarbon contamination sources in soils and aquifers and for the recovery of entrapped oil from low production oil reservoirs. Diverse microorganisms were screened for biosurfactant production and anaerobic growth at elevated salt concentrations to obtain candidates most suitable for microbial oil recovery. Seventy percent of the 205 strains tested, mostly strains of Bacillus mojavensis, Bacillus subtilis, Bacillus ...
Date: August 15, 2005
Creator: McInerney, M.J.; Duncan, K.E.; Youssef, N.; Fincher, T.; Maudgalya, S.K.; Folmsbee, M.J. et al.
Partner: UNT Libraries Government Documents Department