| Generally, after the conventional oil recovery of the first and the second time, oil recovery ratio can only be 30%～40%of crude oil underground, there is still 60%-70% oil left in reserviors. In order to recover petroleum adequately, the technology for oil recovery of third time was raised. However, microbial enhanced oil recovery(MEOR) will probably be one of the main technologies for stabilizing oil, controlling water and enhancing oil recovery in the future for its outstanding characteristics-simplicity, low cost and efficiency, which has advantages compared with other oil recovery technologies.In this paper, we explored the electric charge and composition of the biosurfactant produced by the thermotolerant microbes, strain ZY-1, ZY-2, ZY-3, ZY-10 and JY-5, which were isolated from crude oil. It was proved that the biosurfactants produced by these strains are all glycolipid, anion surfactant.Research results show that all the tested strains can use carbon source to grow and metabolize. The strain ZY-1, ZY-3, ZY-10 and JY-5 could grow and metabolize better by utilizing xylose, strain ZY-2 could grow and metabolize better by utilizing starch.Strains ZY-1、ZY-3 and ZY-10 used xylose fast, ZY-2 and JY-5 used starch fast. Compared with using saccharides or paraffin as single carbon source, when saccharides and paraffin were used as mixed carbon source, the utilization of paraffin could be slowed down by strain ZY-1, ZY-3 and ZY-10, and accelerated by strain ZY-2 and ZY-2.All tested strains can use the paraffin and exogenous saccharide as mixed carbon source to produce biosurfactant, to reduce the surface tension of the fermentation broth, to increase the emulsification of the fermentation broth, and to increase the hydrophobicity of cell, to the maximal extent. Using the xylose and paraffin as mixed carbon source, strain ZY-10 showed the better effect of oil recovery than other strains. |
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