The Study Of Screening,Identification And Biodegradation Characteristics Of P-nitrophenol Degrading Bacteria

In recent years,water pollution has become the main problem in China's environmental pollution,constantly threatening the health of mankind.As one of the major cause of water pollution,industrial wastewater is an urgent need to solve.Pharmaceutical wastewater with its difficult to deal with the characteristics of China's industrial wastewater treatment has become one of the problems.And p-nitrophenol as a major organic interm ediate in pharmaceutical production has become one of the important pollutants in pharmaceutical wastewater.Therefore in this experiment,the high efficiency degrading bacteria were isolated and screened from the soil samples collected near the sewage outfall of a pharmaceutical factory,using p-nitrophenol as the sole carbon source.On the morphological,physiological and biochemical identification and 16 S rDNA identification.Through control of the environmental factors that determine the optimal degradation conditions of strain,at the same time,the degradation process of nitrite were determined,and the dynamics of the degradation of different concentrations of nitrophenol fitting analysis,specific test results are as follows:1.Two strains of p-nitrophenol degrading bacteria were isolated from the collected soil samples,named Y9 and H2 respectively.2.Combined with the feature of colony morphology,physiological and biochemical characteristics,16 S rDNA sequence test results of three factors,identification of strains Y9 and H2,eventually determine the strain Y9 and H2 are Pseudomonas sp.3.The degradation characteristics of degradation strains Y9 and H2 were studied.The amount of nitrite produced during the degradation of the strain was determined,and the process of p-nitrophenol was analyzed by kinetic analysis.Research result:? The production of nitrite during the degradation of strain Y9 and H2 was consistent with the degradation trend of p-nitrophenol;The optimal temperature of strain Y9 and H2 for degradation of p-nitrophenol was 20 ?³0 ?,and the partial degradation of p-nitrophenol could be achieved at 10 ? and 40 ?,by controlling the culture temperature;The suitable shaker rotary speed is 170 r·min-1²00 r·min-1;the suitable pH is 7.0 8.0,the suitable NaCl concentration is 0.60 g·L^-11.0 g·L^-1;? 0.10% of yeast powder,beef extract and peptone,respectively improved strains of biomass and the degradation rate of p-nitrophenol.0.10% of the addition of glucose,although the strain can increase the biomass,but the degradation of p-nitrophenol process has inhibited;? For 100 mg·L^-1 p-nitrophenol,the degradation rate of p-nitrophenol increases with the increase of inoculum size within a certain range.However,under the condition of high concentration of p-nitrophenol(250 mg·L^-1,300 mg·L^-1,400 mg·L^-1,500 mg·L^-1),the inoculum size of the strain could increase the tolerance and degradation of p-nitrophenol;? The degradation of p-nitrophenol by strain Y9 and H2 was in accordance with the first-order kinetics equation when the concentration was less than 350 mg·L^-1.