Isolation Of PAHs-degrading Bacteria,Study On Their Characterization Of The Degradation Metabolism And Environment Safety Impact

Polycyclic aromatic hydrocarbons(PAHs)are a kind of typical persistent organic pollutants with high toxicity,high biological concentration and difficult to degrade.The restoration of polluted environment has always been a hotspot in the field of environmental science and technology.Among them,microbial restoration has great application potential due to its advantages such as low cost and no secondary pollution.In nature,there are abundant sources of biodegradable bacteria.However,due to the poor distribution of pollutants and low mass transfer efficiency in natural environment,it takes a long time for bacteria to evolve into highly effective bacteria.In this paper,with a high concentration of phenanthrene and pyrene as the sole carbon source,since from coking wastewater pollution of soil bacteria and bacteria in activated sludge of wastewater treatment plant for the source,gradually improve the domestication of the concentration of carbon source method,get to the Philippines or pyrene degradation bacteria as the sole carbon source.The degradation characteristics of polycyclic aromatic hydrocarbons and their effects on environmental safety were studied by selecting a highly effective biodegradable bacteria from degrading bacteria.The main research contents and results of the thesis are as follows:(1)In coking wastewater of bacteria in the sediment,sewage treatment plant sludge as bacteria source,after PAHs as sole carbon source gradually increase the concentration of carbon source method of domesticated domesticated,screening of 10 PAHs degradation bacteria was isolated,the morphological differences between each other.By studying the growth curve of 10 strains of bacteria in pyrene and its degradation properties of pyrene,L9 was identified as the dominant biodegradable bacteria.After Biolog physiological and biochemical characterization and molecular biological identification,it was determined that L9 is Rhodococcus ruber.(2)Four kinds of extraction methods on the comparison to the recovery rate of PAHs,four extraction methods used by the instrument of thermostatic cultivation oscillators respectively,ultrasonic cleaning machines,ultrasonic cell broken meter,vortex generator.By comparing the ultrasonic cleaning machine and ultrasonic extraction method of cell disruptor recovery rate is highest,and combining with the experiments of simplicity,eventually choose extraction method of ultrasonic cleaning machine,phenanthrene and pyrene recovery were 85.1±4.6% and 91.2±7.1%.(3)The environmental factors influencing the degradation of the phenanthrene and pyrene were studied,and the best environmental conditions were determined.35 ?,pH is 8.0,the inoculation quantity volume fraction is 15% phenanthrene degradation effect is best;35 ?,pH is 8.0,the inoculation quantity volume fraction is 10% pyrene degradation effect is best,in a comfortable environment under the condition of 50 mg/L 7 days of phenanthrene and pyrene degradation rate can reach 99% and 44.2% respectively.Response surface method to predict when the temperature is 35.84 ?,pH is 8.09,the inoculation quantity volume fraction was 12.06%,the largest degradation rate of pyrene can reach 46.82%.(4)Co-metabolism is a common metabolic method for microbial degradation of pollutants.The addition of phenanthrene and phenanthrene has reduced the degradation rate of pyrene by 10.0% and 13.1% respectively,while the addition of naphthalene has increased the degradation rate of pyrene by 19.4%.Rhodococcus ruber pyrene degradation and degradation of phenanthrene and fluoranthene oxidase reaction system of competitive inhibition,lead to the degradation of pyrene rate is reduced,and the degradation of naphthalene competitive inhibition,enzyme reaction system,can improve the degradation rate of pyrene together.In the same experimental method,the degradation of benzene and pyrene was promoted by naphthalene,which inhibited the degradation of benzo and pyrene,and there was no obvious interaction between pyrene and benzopyrene.(5)By Kirby Bauer-paper AGAR diffusion method to investigate Rhodococcus ruber resistance to 10 kinds of commonly used antibiotics,10 kinds of antibiotics were ciprofloxacin,tetracycline,norfloxacin,cefoperazone,erythromycin,ampicillin,cephalosporins he organism,gentamycin,chloramphenicol and amoxicillin.Rhodococcus ruber to one of the eight kinds of antibiotics for sensitive,only for his organism characterized by mediation,cephalosporin showed resistance to amoxicillin,Rhodococcus ruber overall performance is sensitive to commonly used antibiotics.(6)Use of broad bean root tip cells micronucleus test characterization of the genetic toxicity of Rhodococcus ruber,use fee type Aliivibrio fishieri biological toxicity test,analysis of polycyclic aromatic hydrocarbons in the metabolic production of Rhodococcus ruber the change of the acute toxicity,the experimental results show that collected aureus micronucleus rate of broad bean root tip cells caused no significant effect,Rhodococcus ruber degradation of phenanthrene and pyrene process won't produce a greater biological toxicity of metabolites to affect the safety of the ecological environment.