[Effects and Biological Response on Bioremediation of Petroleum Contaminated Soil].

Bioaugmentation and biostimulation were used to remediate petroleum-contaminated soil which were collected from Zichang city in North of Shaanxi. The optimal bioremediation method was obtained by determining the total petroleum hydrocarbon(TPH) using the infrared spectroscopy. During the bioremediation, number of degrading strains, TPH catabolic genes, and soil microbial community diversity were determined by Most Probable Number (MPN), polymerase chain reaction (PCR) combined agarose electrophoresis, and PCR-denaturing gradient electrophoresis (DGGE). The results in different treatments showed different biodegradation effects towards total petroleum hydrocarbon (TPH). Biostimulation by adding N and P to soils achieved the best degradation effects towards TPH, and the bioaugmentation was achieved by inoculating strain SZ-1 to soils. Further analysis indicated the positive correlation between catabolic genes and TPH removal efficiency. During the bioremediation, the number of TPH and alkanes degrading strains was higher than the number of aromatic degrading strains. The results of PCR-DGGE showed microbial inoculums could enhance microbial community functional diversity. These results contribute to understand the ecologically microbial effects during the bioremediation of petroleum-polluted soil.

[Effect of Mn2+ on pyrene degradation by Flavobacterium sp. FCN2].

Mn2+ concentration affecting polycyclic aromatic hydrocarbon pyrene degradation by the Flavobacterium sp. FCN2 was investigated by adding Mn2+ during several periods, which including bacteria cultivation period, bacteria degrading pyrene and enzymatic degradation period. Results show the concentration of Mn2+ was beneficial for pyrene degradation, and Mn2+ was no influential to bacteria growth and magnitude. When Mn2+ was added during culturing strain FCN2 period, bacteria FCN2 can enrich Mn2+, and pyrene removal efficiency by Mn2+ enrichment bacteria is 1.26 times more than that of without Mn2+ enrichment bacteria. As well as the situation that adding Mn2+ during FCN2 degrading pyrene period that pyrene removal efficiency is 1.67 times more than that of without Mn2+. And when adding Mn2+ during enzymatic degradation periods, the elimination efficiency of pyrene was 1.30 times more than that of without Mn2+.