Isolation And Identification Of Pyrene Degrading Strains And Preliminary Study Of Pyrene Degradation Characteristics Of The Strains

Polycyclic aromatic hydrocarbons (PAHs) are a class of organic chemical pollutants consisting of two or more fused benzene rings, widely distributed in environment. They have attacted more intensive attention because they are carcinogenic Teratogenic and mutagenic to animals and human being potentially. Microbial remediation was proved to be the best way to remove PAHs pollution. It is not only economical, efficient, and thorough treatment, less residue.Pyrene is a kind of PAHs containing four benzens. It does not have cell toxicity, but its metabolites quinone has carcenogenic after being intaken by human body. Generally low molecular weight PAHs can be more easily used by microbes in the environment, and high molecular weight PAHs are not likely to be used to remain in the environment. As the more benzene rings the PAHs have the more toxic they are, microbial degradation of high molecular weight PAHs caused more and more attention of scholars. Pyrene is often used as a model compound to study the degradation of high molecular PAHs.Type and content of 16 kinds of PAHs of the soil samples collected from Jinan refinery was determined with three different methods. The results showed that the sample contained all the 16 PAHs. The content of pyrene was more than 400 (ug/kg, came in the third place among all the PAHs. Two strains named 3B and 3C which can use pyrene as the sole carbon source and energy source for the growth were isolated from the samples.In this study, strain 3B was identified as Alcaligenes faecalis ss faecalis,3C for the Bacillus subtili with multi-phase identification technology. The optimum temperature of strain 3B and 3C is 30℃. Optimum growth pH value is 7.0 for strain 3B and 9.0 for strain 3C. Neither of the two strains contain plasmid, which indicated that degradation genes local in the genom. Strain 3B has a strong resistance to the 7 testing antibiotics. Two strains could grow well using 13 kinds inorganic carbon source as the sole carbaon source and energy source. Pyrene degradation efficiency and the growth curve of the two strains was determined with the optimized medium. Degradation efficiency of pyrene by strain 3B is 42.44% and 24.15% by strain 3C.