Isolation of Achromobacter xylosoxidans subsp. denitrificans and it's degradation of phenanthrene

Isolation of polycyclic aromatic hydrocarbon-degrading bacteria was conducted in plate medium using selective enrichment culture.Two isolates of FC31 and FC32 were obtained by the means of sublimation from petroleum-contaminated soil.Both strains grew well on sole carbon of phenanthrene and degraded it efficiently.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 were of catechol dioxygenase activity and higher phenanthrene-degrading capacities in the broth assay with about 90% of phenanthrene added being degraded during 60 hours incubation.The quantity of phenanthrene degradation was correlated with the OD value.The results indicated that the ability of phenanthrene-degrading was strongly increased when they were used as a mixture.