| The exploitation of oil has been developed and applied rapidly with the process of industrialization. However, there are a large number of oil-bearing soil during the exploitation and refining, which has resulted in oil pollution more seriously. Diesel oil is a kind of complex mixture, consisted of a paraffin, aromatics and fatty material. For it's low solubility in water, diesel oil can hardly be removed by way of biodegradation, then the decomposition of soil oxidation of diesel would be much more slowly than other pollutants in the nature.As a kind of compounds consisted of hydrophilic and hydrophobic, Biosurfactants always come from microbial synthesis. They are solubilization, wetting, penetrating, low-toxic, biodegradable, eco-compatibility, high efficient and stability. The efficiency of diesel degradation can be improved by two ways: on the one hand, they help aqueous and other insoluble materials spread into the cells, for which the compounds can be degraded more easier; On the other hand, the hydrophobic properties between microbial cells and hydrocarbons on the surface of cell can be regulated by biosurfactants, by which diesel degradation can be more effectively.Firstly, 7 biosurfactant producing strains, obtained from the restaurants'sewage by method of microbe cultivation, one (B26) of which could produce surfactant high efficiency by a series of sreening process. The fermentation of B26 could be reduced from 67.2mN/m to 36.8mN/m. B26 had the largest absorption peak suspension at wave-length of 600nm by UV2550. Based on the morphological, physiological and biochemical test results, B26 was identified as bacillus sp.Secondly, This article had explained a set of simple and effective screening ways according to microorganism culture, orthogonal experiment. The best growing conditions of B26 was obtained successfully: K2HPO4 4.0g/L, KH2PO4 10.0g/L, CaCl2 2 H2O 0.1g/L, NaCl 1g/L, KCl 1 g/L, (NH4)2SO4 1g/L, NaNO3 2g/L, MgSO4·7H2O 0.2g/L, yeast paste 0.4g/L, soluble starch 1g/L, EDTA 1g/L, KI 0.83μg/L, H3PO40.01μg/L, CoCl·6H2O 0.048μg/L, MnSO4·H2O 0.312μg/L, Na2MoO4·2H2O 0.048μg/L, ZnC12 0.287μg/L, CuSO4·5H2O 0.125μg/L, with initial pH 7.5 and the temperature 30℃, 170rad/min. The emulsifying capacity of B26 was stable, CMC 130mg/L, in whose metabolism lipopeptide biosurfactant could be produced, and 0.57g/L of them could be extracted using the freeze-drying method. In order to find out how did surfactant made effect on the process of diesel degradation, seven biosurfactant producing strains, obtained from restaurants'sewage, were respectively interacted with a diesel degradable bacteria-J1(a kind of Pseudomonas strains obtained also in lab) to study the influences of biosurfactants on diesel degradation. The interaction showed that B26, one of the seven strains, could not only reduce the degradation induction peoriod from 6 days to 4 days but also increase the degradation rate from 71.1% to 80.6%, which deserved further research. All tests were focused on analysis of mechanism and the affected factors in diesel degradation, which would provide strong basis for the strain and biosurfactants applied in oil-contaminated soil and water.
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