Isolation, Identification And Characterization Of Gasoline Degrading Bacteria

Gasoline, which is widely used as the most common fuel, can be harmful to human life as well because of misuse in restoring transportation and refining, though it is of great use to human. Gasoline can be absorbed in human body by the alimentary canal, the respiratory tract and skin. It can cause the edema of the mucous membrane, the injury of liver and kidney. To make things worth, the gasoline can cause cancer. The soil contaminated by gasoline has bad affects on the growth of crops and vegetables. Thus, effective measures must be taken to clean the soil samples polluted by gasoline.This article generally described and discussed the mechanism of the biodegradation bacteria. The soil sample is obtained from a gas station which is in Southenton, CT, United states. The bacteria named MM3 which can degrade gasoline or octane and use it as the only carbon source when it is necessary. The bacteria is studied by using biochemical measures. And the 16s rDNA of the bacteria is sequenced. Finally it is identified as a type of Pseudomonas aeruginosa.Respectively the optimal pH, temperature and gasoline mass concentration are 8 ,25℃and 1000 mg/L.Since surfactants can increase the bioavailability of gasoline and enhance the degradability of gasoline by bacteria. Certain kinds of surfactants are added to test which type can best help the bacteria degrade the gasoline. The effect of the TW-80 is better than the effect of the other one. However, the density of surfactants which if higher than normal is harm to the growth of the bacteria.The mutants by ultraviolet radiation treatment had greater degrading efficiency than the original ones,with 30 W ultraviolet light having better mutation effect on the strains than 15 W ultraviolet light. The bacteria represent a degrading efficiency when both ultraviolet light and lithium chloride are used.For octane is one of main ingredients of gasoline, gasoline is substituted by octane in another research to test the optimal pH,temperature and gasoline mass. The result is that when octane is used as the only carbon source, the optimal pH, temperature and gasoline mass are the same as before. But both the growth and degrading rate have decreased compared to when gasoline is used as the carbon source.