Studies On Phyto-microbial Remediation Of Pyrene-contaminated Sediment

Polycyclic aromatic hydrocarbons (PAHs), which consist of two or more fused aromatic rings, are wide spread in the environment and persist over long periods of time. The decontamination of PAH-polluted environment is of importance because some PAHs are toxic, mutagenic, and carcinogenic and therefore are health hazards. Phyto-microbial Remediation of PAHs, by its unique merits, has received great attention.In this study, three strains of pyrene-degrading bacteria were isolated from Liaohe river sediment. They were identified as Paracoccus versutus H11, Shinella granuli H17 and Alcaligenes sp. F8 using of physiological-biochemical and sequencing of 16S rDNA methods.Study on Optimization of Cultivation Condition, the optimal pH and temperature for H11, H17, F8 growth was 7.2,7.2,6.5 and 32℃,37℃,37℃. Different heavy metal ions on growth were investigated. Results showed that Pb2+(200mg·L-1) had little influence to the growth of H11, Inhibited H17 and promoted growth of F8. Cd2+(100mg·L-1) was toxic to the bacterium strains. Zn2+(100mg·L-1) had Inhibitory Effect to strains. Cu2+(50mg·L-1) had no significant influence on the growth of H11 and F8, but had inhibition to H17.The relatively high degradation efficiency of pyrene by bacterial strain F8 was examined. The degradation rate of pyrene (50mg·L-1) was 62.8% after 7d. The degradation rate of pyrene could reach 68.8% and 79.6% when salicylic acid (50mg·L-1) or glucose (50mg·L-1) was coexisting with pyrene after 7d. Meanwhile, the degradation rate of pyrene under different pyrene concentrations was determined. It was shown that after 7 days of cultivation, the degradation rate under pyrene concentrations of 50-200mg-L"1 were downtrend.Effects of bacterial strains F8 on pyrene degradation in PAHs and heavy metal contaminated river sediment were investigated by pot culture experiment. The result showed that the rice could promote the degrading of pyrene and raise the degradation rate effectively (11.9%).The study provided microbial resources for bioremediation of pyrene polluted river sediment, and academic basis for the phyto-microbial remediation technology.