Abstract: Three strains of Bacillus sp.BA11,BA19 and BA27,which can grow when phenanthrene is taken as the sole source of carbon and energy,were isolated from an oil-contaminated soil.Their crude extract was used to test the activities of polyphenol oxidase and catalase.The results demonstrated that all the three strains did not show a significant change in the activity of both enzymes when phenanthrene was lower than 200 mg稬^-1 .Under different phenanthrene concentration,the enzyme activities of strains BA19,BA27 showed a higher stabilization than BA11.Using the SDS-PAGE contrasted the difference of proteins between the strains in normal medium and the strains growing on phenanthrene,the results showed that BA27 growing on phenanthrene synthesized a new protein with 27 000 dal of molecular weight.At the same time,the synthesis of some proteins was cancelled.We conjecture that the new protein induced by phenanthrene may be related to the ability of phenanthrene degradation and the stabilization of enzyme activity by the strain.

Key words: Phenanthrene, Degradative bacterium, Enzyme activity, Bioremediation