Title : Biosurfactant production using egyptian oil Fields indigenous bacteria for microbial enhanced oil recovery
Abstract:
The US Energy Information Agency (EIA) predicts that hydrocarbons will remain the primary energy source to satisfy the surging energy demands in the near future. Microbial Enhanced Oil Recovery MEOR is a cost-effective and ecofriendly technique that exhibits many advantages comparing with the other conventional Enhanced Oil Recovery EOR techniques where it has no need of huge amounts of energy, like thermal techniques, and it does not depend on the oil price, like many chemical techniques. On other hand, MEOR could be easily applied after simple adjustments to the existing field facilities, and it is able to produce up to 50% of remaining oil.
Combined analysis of morphological, and biochemical characterization was performed on the bacterial strains isolated from Egyptian crude oil sample located in Western Desert to identify its genera. To optimize the surface activity of the produced biosurfactant, bacterial strain was grown in 10 different reported nutrient media, and a new proposed nutrient medium H. The growth rate of bacterial strain was studied using the optical density method. The emulsification activity of the produced biosurfactant was examined by measuring the emulsification index E24. The produced biosurfactant was purified and extracted by acid precipitation method. Finally, stability studies of the produced biosurfactant was done under different conditions (temperature, salinity, and pH).
Results showed that the isolated bacteria strain was Bacillus subtilis. Bacillus subtilis has been isolated from Egyptian oil fields located in Western Desert, in terms of producing metabolic biosurfactant from indigenous bacteria to improve the oil recovery. It was found that Bacillus subtilis has the ability of producing a highly active biosurfactant. It was found that the maximum surface tension (25.74 mN/m), and interfacial tension against kerosene (0.38 mN/m) was observed after 24 hours of incubation in the new proposed nutrient medium H. The growth profile of Bacillus subtilis was investigated, the maximum growth rate (2.072 x 109 CFU/ml) was observed after 24 hours of incubation. The produced biosurfactant was extracted and purified from culture media, and the biosurfactant yield was about 2.853 g/l. the critical micelle concentration CMC was also determined, it was 0.04 g/l at minimal surface tension 25.74. The stability of produced biosurfactant in different conditions (temperature, salinity, and pH) was investigated. There was no notable change in surface activity over a wide range of temperature up to 120oC, which means Bacillus subtilis is thermophilic and could tolerate the harsh temperature of oil reservoirs. The surface activity of produced biosurfactant exhibited high stability against salt concentration, even at high NaCl concentration up to 20%, it retains more than 60% of its surface activity, which means it could tolerate the harsh salinity of oil reservoirs. The optimum salinity of the produced biosurfactant was in range of 0 to 2% NaCl concentration. The optimum pH value of the produced biosurfactant was observed at neutral values. The emulsification activity of the produced biosurfactant was confirmed, and it was noticed that the maximum emulsification power against kerosene was 69.52%.
Audience Take Away:
- This work concerned with investigating the capability of production of biosurfactants by indigenous bacteria isolated from Egyptian oil field, and how to optimize these produced biosurfactants.
- This work Identified the indigenous bacteria that can be isolated from Egyptian crude oil sample.
- This study identified the kinds of indigenous bacteria from sampled Egyptian oil fields.
- The effect of some nutrients on the growth of the selected bacterial strains will be Investigated.
- This work performed several experimental studies to study the stability of the produced biosurfactants at harsh reservoirs conditions (salinity, pH, and temperature), and determine the optimum conditions for the produced biosurfactants to reach maximum surface activity.
This work carried out several modelling studies in a sand-pack model to investigate the effect of produced biosurfactants on oil recovery.
