Study On The Selection And Identification Of Hydrocar-degradation Bacteria And Hydrocar-degradation Efficiency

Development is the theme of today’s world, especially the developing countries like china. In recent years, china growing faster than our imagine. The rapid development need a large number of energy, so petroleum exploration and wastewater emissions from chemical industry lead severe hydrocarbon pollution. On the other hand, the hydrocarbon pollution is far more than the self-purification capacity of the environment. The hydrocarbon pollution has the following characteristics, fast generation rate, widely range and form, long natural restoration, harmful to humans and so on. So pollution of hydrocarbon is very serious now. To solve the hydrocarbon pollution, this study works on screening, separating and identifying the effective hydrocarbon-degrading microorganisms. And analyses the characteristics and potency of degradation.In this study, soil samples were collected from Daqing petroleum contaminated soil. Used n-hexane and naphthalene as sole carbon source to enrichment and screen the hydrocarbon-degrading microorganisms. Three different kinds of highly effective hydrocarbon-degrading microorganisms were separated, named PD-5, PD-6and PD-7. This study identified PD-5, PD-6and PD-7as Pseudomonas chlororaphis, Citrobacter braakii and Serratiaficaria.The study find hydrocarbon degradation named PD-6is more efficiency than the PD-5and PD-7through the single factor experiment and response surface analysis. This study acknowledged the best growth factor of PD-6is29.91℃, pH7.81, inoculum size(OD6oo=0.5)1.83%.Used GC-MS to analysis the changes about the hydrocarbon composition of crude petroleum before and after the degradation of PD-6.The study found PD-6have good degradation and removal efficiency to hydrocarbons of C12to C50, especially, PD-6’s degradation efficiency to hydrocarbons of C20to C30reached49.6%. This study used infrared spectrophotometry to analyze petroleum changes in single factors. This study found the best conditions for petroleum degradation of PD-6is30～32℃, pH8, crude petroleum concentration200-600mg/L.