Five dominant bacteria strains(Acetobacter sp., Alcaligenes sp., Micro coccus sp., Arthrobacter sp. and Bacillus sp.) and five fungi strains(Cephalospo rium sp. I, Cephalosporium sp. II, Aspergillus sp. I, Aspergillus sp. II and Fus arium sp.) isolated from petroleum-contaminated soil were used to assess the pot ential capability of mineral oil and PAH enhanced degradation separately and joi ntly using the batch liquid medium cultivation with diesel oil spiked at 1000 mg /L. The experiment was performed on a reciprocal shaker in the darkness at 25℃ to 30℃ for 100 d. The dynamic variation in the activity of microbial inoculator s in each treatment and the degradation of the target pollutants during the peri od of experiment were monitored. Results showed a more rapid biodegradation of m ineral oil and PAHs at the beginning of the experiment(about 20 d) by dominant b acteria, fungi and their mixture than that of the indigenous microorganisms, how ever, thereafter an opposite trend was exhibited that the removal ratio by indig enous microorganisms was superior to any other dominant treatments and the tende ncy lasted till the end of the experiment, indicating the limited competitive ca pability of dominant microorganisms to degrade the contaminants, and the natural selection of indigenous microorganisms for use in the removal of the contaminan ts. At the end of the experiment, the removal ratio of mineral oil ranged from 5 6.8 % to 79.2 % and PAHs ranged from 96.8 % to 99.1 % in each treatment by micro bial inoculators.
