Screening of microorganisms for microbial enhanced oil recovery processes

The objective of this study is to screen effective microorganisms for the M icrobial Enhanced Oil Recovery process (or simply as MEOR). Samples of dril ling cuttings, formation water, and soil were collected from domestic drill ing sites and oil fields. Moreover, samples of activated-sludge and compost were collected from domestic sewage treatment facility and food treatment facility. At first, microorganisms in samples were investigated by incubati on with different media; then they were isolated. By two stage-screening ba sed on metabolizing ability, 4 strains (Bacillus licheniformis TRC-18-2-a, Enterobacter cloacae TRC-322, Bacillus subtilis TRC-4118, and Bacillus subt ilis TRC-4126) were isolated as effective microorganisms for oil recovery. B. licheniformis TRC-18-2-a is a multifunctional microorganism possessing e xcellent surfactant productivity, and in addition it has gas, acid and poly mer productivities. E. cloacae TRC-322 has gas and acid producing abilities . B. subtilis TRC-4118 and TRC-4126 are effective biosurfactant producers, and they reduce the interfacial tension to 0.04 and 0.12 dyne/cm, respectiv ely.