الملخص الإنجليزي
Microbial Enhanced Oil Recovery (MEOR), makes use of microorganisms and their metabolic products to improve the recovery of crude oil from the reservoir. These metabolites include biosurfactants, biopolymers, acids, solvents and gases. Each of the metabolites has its role in enhancing oil recovery, and bacterial strains may produce some of these metabolites. In this project; 70 samples were collected fro different garages, petrol stations and from Petroleum Development Oman (PDO) oil fields; Sultanate of Oman. Forty oil contaminated soil samples were collected from the garages and 20 from oil fields. Moreover, 7 crude oil samples, 2 injection water samples and 1 mud cutting sample were from oil fields as well. Twenty-six of the isolates which were from the soil were able to grow at 60°C and under anaerobic
n. However, only 16 isolates which were from the soil were able to tolerate under high saline condition (150000 ppm of NaCl) and able to secrete higher concentrations of biosurfactant (around 22.7mN/m) and biopolymers (about 0.53 cP). Whereas some of the bacterial isolates produced very little biosurfactant when screened using oil spreading technique and very little biopolymers which was seen by the formation of less mucoid colonies. Four isolates were selected for further studies using viscometer and tensiometer. No acid or gas was generated at 15% salinity. The 16 strains were checked for the compatibility test. Using the API system, it was identified as, Geobacillus thermoglucosidasius, Bacillus megaterium, Bacillus subtilis/amyloliquefaciens, Aneurinibacillus aneurinilyticus, Brevibacillus spp, Bacillus pumilus and Bacillus spp. However, using DNA sequencing method, it was found that all of the isolates were Bacillus licheniformis with 99% identity.
