Characteristics And Related Enzymes Of The Thermotolerant Strains For MEOR

Microbial enhanced oil recovery technology exhibits the advantages, of simple operation, low cost, adaptability, possess safety and environmental friendship. Moreover, MEOR has become the favorable EOR method with promising developing prospect. Its application and development have extremely important significance for sustainable development of petroleum industry.In this paper, eight thermotolerant strains isolated from crude oil were indentified by physiological and biochemical characteristics. The results show that strain ZY-1is Arthrobacter, strain ZY-2is Micrococcus, strains ZY-3, ZY-10, ZY-11, JY-5, JY-6and JY-11are Bacillus.Under the condition that the carbon sources were glucose, sucrose, xylose, starch and cellulose, cell density and surface tension of fermentation broth were selected to determine the main growth and metabolism characteristics of eight tested strains. The results indicated that xylose was optimal carbon source. Strain ZY-10could utilize variety of carbon sources for growth and metabolism, it was suitable for oil recovery.When hydrocarbon and cellulose or starch were used as carbon source respectively, strains ZY-3and JY-11were evaluated on emulsification, cell density and enzyme activity related to substrate degradation of fermentation broth at various pH. The relationship between the enzyme activity and fermenting property of strains would be established at initial pH6.0. The optimal pH for growth and metabolism of strains was pH6.0. when inoculum medium contained cellulose, growth of strain JY-11was restrained, and biosurfactant production wasn’t changed significantly to strains ZY-3and JY-11. The growth and biosurfactant yield of the strains were promoted when fermentation medium contained cellulose and inoculum medium contained starch. Starch contained in fermentation medium would inhibit the growth and related metabolism of strain ZY-3, but it promoted the growth and biosurfactant production of strain JY-11. The different medium had not obvious effect on cellulase and amylase activity. When strain ZY-10was cultured in the media with xylose and paraffin as mixed carbon sources, xylose was utilized earlier than paraffin, paraffin was utilized more quickly than in the media with paraffin as sole carbon source, and the biosurfactant yield was higher than in the media with xylose or paraffin as sole carbon source.