Polycyclic aromatic hydrocarbons (PAHs), which consist of two or more fused aromatic rings, are widespread in the environment and persist over long periods of time. The decontamination of PAH-polluted environment is of importance because some PAHs are toxic, mutagenic, and carcinogenic and therefore are health hazards. In this paper, isolation of polycyclic aromatic hydrocarbon-degrading bacteria was conducted in plate medium by selective enrichment culture. Two isolates of FC31 and FC32 were obtained by the method of sublimation from petroleum-contaminated soil;FC31 was identified as Bacillus firmus and FC32 as Achromobacter xylosoxidans subsp. denitrificans based on analysis of 16S rDNA sequence and Biolog-GN profile;Both strains grew well on sole carbon of phenanthrene and degrade it efficiently and both strains showed catechol dioxygenase activity and higher phenanthrene-degrading capacities in broth assay;The amount of phenanthrene degradation was correlated with the OD value. The results indicated that the ability of phenanthrene-degrading increase greatly when they were used as a mixture;With the method of plasmid elination,it was proved the genes encoding for degradation of phenanthrene locate on a plasmid;Study showed that different nutritional elements had significant effects on phenanthrene-degrading rates and phenanthrene uptake of crops in soil, but different organic amendments had insignificant effects on rice biomass and the emumeration of phenanthrene-degrading bacteria.
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