Study On Immobilized Cells And Enzymetic Degradation Of D3 To Chlorpyrifos In Water

Chlorpyrifos is the substitute of high-toxicity Organophosphorus Pesticides,it is widely used in agriculture and daily lives.With the improvement of toxicology study on Chlopyrifos,its harm to the enviroment,human and animals is known by people.In this study,we use Chlorpyrifos as the primary pollutant,its GC analytical method,the spectrum of biodegradation on Organophosphorus pesticides,immobil -ization of the bacteria and degradative characteristics of immobilized cells,extraction of the degradaing enzyme and degradative characteristics of the degradaing enzyme. The results are as follows:1.As the result of biodegradation-spectrum goes,the biodegradation rates of the bacteria on parathion,parathion-methyl,fenitrothion and malathion are 99%,98%,88.7%,76.9%in 24h.With concentration of 10⁷ CFU·mL^-1 of the bacteria,the half-life of the pesticides are 3.830h,3.501h,5.004h,10.830h.2.In the study on immobilizing of the bacteria,we choose weight of the bacteria,concentration of CaCl₂,concentration of sodium alginate and hours of immobilizing time as factors of the orthogonal test.The degradation of immobilized cells on Chlorpyrifos was detected.The results indicate that the best level of the four factors are:3.0g,4%,2%and 8h.3.The characteristics of degradation of the immobilized cells on Chlorpyrifos indicate that,the immobilized cells had optimum temperature of 30℃and optimum pH of 7.0 on degradation of Chlorpyrifos.The immobilized cells had steady absorbtion of Chlorpyrifos and was not releasd again.It was shown that immobilized cells embed-ded with complex carrier had favorable mechanical intensity and penetration capability,in the basis of the test results.4.The extraction condition of the degrading enzyme was studied.The results indicated that the degrading enzyme was located inside the cell of the isolated strain Rhodococcus rhodochrous.Under inducing and non-inducing experiment,we found that the an uninducing one.5.The soluble protein of the crude enzyme was 1.295 mg·mL^-1,determined with Albumin(bovin scrum)as standard.The Km value and the maximal enzymetic degradation rate for Chlorpyrifos was 0.7899mmol·L^-1 and 0.14415μmol·min^-1.Under temperature of 25℃and pH of 6.5,the enzyme had optimum degradation rate for Chlorpyrifos.When preserved in the condition of pH of 7.0 and temperature of 10℃,the enzyme still had optimum degradation rate for Chlorpyrifos.