Abstract: A total of 10 bacterial strains represented as from SB01 to SB10 were isolated from a petrolium-contaminated sludge, and their potential of degrading pyrene (PYR) was investigated on the substrates pyrene (MS₁), pyrene plus glucose (MS₂), and pyrene plus phenanthrene (MS₃). The results showed that on MS₁, the degradation rate of PYR by SB01 was the highest, with 30.4% of PYR degraded after 5 days. On MS₂, the degradation rate of PYR by SB09 was the highest, being 37.7% after 5 days, while on MS₃, 50.2% of PYR was removed by SB01. The degradation of PYR by SB01 and SB03 was inhibited by glucose, which was more obvious for SB01, but no significant difference was observed among SB02, SB07, SB08 and SB10. The biodegradation rate of PYR by all the ten bacterial strains was enhanced on MS₃, and that by SB10 was increased by 29.8%. For SB04 and SB09, the biodegradation rate of PYR had no significant difference between MS₁ and MS₂, but for other strains, the stimulation effect of phenanthrene on PYR degradation was higher than that of glucose.

Key words: Horqin desert land, Land use, Temporal and spatial change