The Optimal Culture Of A Biosurfactant-Producing Strain And The Application Research In Heavy Oil Viscosity Reduction

A high-efficiency biosurfactant-producing strain H1 was isolated from polluted soil of an oil field with blue agar plat. The strain was analyzed of physiological biochemical test and similarity analysis of 16s rRNA. The approval test was conducted in order to determine the species. And extract the metabolite for thin layer chromatography and infrared spectroscopy test, then the composition of product was analyzed and to determine if whether it contains the biological surface active components and what kind of biosurfactant it is. Results showed the strain was identified as Klebsiella pneumoniae. TLC and infrared spectrum indicated that the product had color reaction with phospholipids indicator. According to infrared spectral data, there is obvious (C=O) and phospholipids (P-O-C). Turning out H1 biosurfactant was phospholipids biosurfactant. The yield of biosurfactant produced by strain H1 could reach 0.7 g/L.An efficient biosurfactant-producing strain A3 was isolated from the soil of Liaohe oil field by the methods of oil plate screening model and oil spreading. And named it as A3.According to the analysis of physiological and biochemical characteristics and 16SrRNA sequences, identification the strain. The strains was identified as Pseudomonas aeruginosa. The product was extracted and purified, and according to thin layer chromatography and infrared spectroscopy to determine whether the product is biosurfactant and determine the type of its products. An orthogonal optimization test for fermentation conditions of strain A3 was made, optimization experiments indicators were carbon, nitrogen, temperature, pH and NaCl concentration. An important indicator of performance evaluation of biological surface active agent is its stable performance, And to determine the critical micelle concentration (critical micelle concentration, CMC), in order to get on for the following crude oil viscosity reduction experiments, and the stability of biosurfactant and the determination of heavy oil viscosity reduction were investigated. The crude oil viscosity reduction experiments include the relationship of viscosity and temperature of heavy oil. The effect of different adding state of biosurfactant on viscosity reduction of heavy oilThe results showed that the optimal conditions for the biosurfactant synthesis were as follows:glucose 30 g/L, sodium nitrate 4 g/L, sodium chloride 4 g/L, initial pH was 6, and the optimal cultivation temperature was 30℃. Under the optimum conditions, the strain A3 could produce biosurfactant 5.5 g/L which was 5.4 times higher than that under the initial conditions. The biosurfactant produced by strain A 3 has good thermal stability and salinity stability. The viscosity reduction rate of 96.7% could be obtained under optimal conditions by biosurfactant from strain A3.The results of this study could provide a new source of bacteria to synthetic biological surfactants. But also for improving the biological synthesis of surfactant provides a scientific basis, and the good stability conducive to broaden the application of biological surfactants, which can lay foundations for the development and application of new surfactants.