Screening High Efficiency Strains Of Degrading Nitrogenous Heterocyclic Compounds And The Application In Bioremediation

In order to screening strains with high biodegradation efficiency of nitrogenous heterocylic compounds and applying strains to oil contaminated soil, optimizing the conditions of stains, construction mix culture and domesticating strains, utilizing immobilization technology for bioreactor were investigated in this thesis.Quinoline and pyridine degrading bacterias were isolated by enrichment from 45 soil samples from various areas of China, especially polluted site by petroleum. Four high efficiency strains were selected for the biodegradation study. An alignment of the DNA sequences of the 16S rRNA gene of the bacterium with DNA sequences, available in GenBank database indicates that strain 2-13 is closest designated as Flexibacter giganteus, strain 4-11 is designated as Thiobacillus intermedius, strain Q5 is designated as Lactobacillus fermentum, strain Q24 is designated as Arthrobacter flavescens. The primary conditions were reviewed, such as pH value, temperature, rotation speed, inoculum size, carbon and nitrogen sources, the concentration of target etc.The initial mix culture after domesticated had excellent degradation as single strains, but shorter domestication period and easy manipulation. Artificial constructed mixed strains don't have ideal effect, only 43.2%~57.1%.After immobilizing, the strains capacity of degradation was extremely enhanced. Compared with the untreated, the immobilized strains have a wide range on pH value and temperature, and higher degradability. At initial concentration 1500mg?L-1 of quinoline, the degrading rate in the bioreactor Q5 in 70 hours treatment coulde reach to 86.5%, and had steady effect.Bioreactor Q5 were appled to biodegradate oil contaminated soil in Shengli Oilfield, pyridine was biodegradated completely after 20ds, and the degradation rate of quinoline reach to 96.5% after 40d.