Studies On The Impact Of Dispersants And Biodiesel On Oil-degrading Microorganisms Diversity

Oil is an important energy to today’s society. With the rapid progress anddevelopment of human society, the demand for oil increased significantly, which leadsto a lot of oil being into the sea and other waters every year due to unexpected events,causing extremely serious consequences. This constitutes a serious damage andthreats to the marine ecological balance. After the oil leak, Dispersants are oftenadded to the ocean for the first time to reduce the impact of oil pollution on the sea asmuch as possible, and biodiesel will be dosed in subsequent bioremediation process topromote biodegradation of oil. Dispersants and biodiesel dosing may haveimplications on the impact of oil-degrading microorganisms. For now, research aboutvariation of oil-degrading microbial diversity in oil pollution seawater by dispersantsand biodiesel has not been focus systemly.Therefore, this study will be based on molecular biology clone library techniquesand PCR-RFLP method. Research and analysis the impact of dispersants andbiodiesel on oil-degrading microorganisms diversity, and the results are as follows:(1)As the dispersant dosage increases, the advantage bacterias ofoil-contaminated seawater gradual transition from Alcanivorax app., Marinomonasapp., Flavobacterium app. and Achromobacter app. to Parvibaculum app. andThalassospira app..(2)As the biodiesel dosage increases, the advantage bacterias of oil-contaminatedseawater gradual transition from Alcanivorax app., Parvibaculum app. andMarinomonas app. to Thalassospira app., Novosphingobium app..(3)Biodiesel can promote microbial growth and improve the efficiency ofbiodegradation better than dispersant. At the same dosage, the number ofmicroorganisms and oil degradation rate of water containing biodiesel be higher thanthe water containing dispersant.(4)NCBI results show that in the16S rDNA clone library, only50%-70%of theclones can be found in the NCBI. Therefore, it was show that many oil-degrading microorganisms had not yet been cultured, classified, and identified.(5) Proteobacteria, Flavobacteria and Actinobacteria are main bacteria in the oilpollution water. And in these bacteria, α-Proteobacteria and γ-Proteobacteria aremain advantage bacteria. Dispersant can promote the growth of γ-Proteobacteria andFlavobacteria, yet biodiesel can promote the growth of α-Proteobacteria.(6)Dispersants and biodiesel can promote the growth of aromatic hydrocarbondegrading bacteria, and as the dispersant and biodiesel dosage increases, theproportion of aromatic hydrocarbon degrading bacteria in seawater increase gradually.This results show that adding biodiesel and dispersants can promote the degradationof aromatic hydrocarbon.