IDENTIFICATION OF INDIGENOUS CULTURES OF MICROORGANISMS OF THE GENUS BACILLUS AND THEIR POTENTIAL APPLICATION FOR ENHANCED OIL RECOVERY

Abstract

The present study was conducted to isolate active Bacillus cultures from developed oil reservoirs as potential objects for the development of microbial enhanced oil recovery (MEOR) methods. Oil formation water from two oil fields "Zhetybai" and "Kulsary" located in Western Kazakhstan were used as study materials. 8 cultures of Bacillus genus were isolated and identified on the basis of phylogenetic analysis of 16S rRNA gene. The formation of acetic acid and biosurfactants were studied as target properties valuable for MEOR. It was revealed that the investigated microorganisms are able to synthesize acetic acid as well as fatty acids. Emulsifying activity was determined as an indicator of the presence of biosurfactants. The maximum emulsification index was observed in strains of Bacillus sp. ZhM-3 and Bacillus sp. KM-2 for crude oil - 80% and 65%, for hexane - 69% and 50%, respectively. As a result of this work it was shown that the cultures of Bacillus sp. ZhM-3 and Bacillus sp. KM-2 are active producers of organic acids (acetic and butyric acids) and biosurfactants capable of emulsifying crude oil, which makes them potentially effective for application in biotechnological processes aimed at enhancing oil recovery from depleted fields.