Study On The Chiral Degradation Of Organop Hosp Hate Pesticide By Microorganism

On the one hand organophosphorus pesticides bring huge economic benefit to farmers and agriculture, on the other hand also bring environment pollution on soil, air and water, posesing a great threat to human health. Therefore, it is a matter of great practical significance to study the degradation of organophosphorus pesticide. At present the main methods of degradation of organophosphorus pesticide are photochemical degradation, chemical degradation and biodegradation ways. Biodegradable, with its high efficiency, thorough, no secondary pollution occupies the important position. Organic pollutants in the environment into CO2 and H2 O,nontoxic and harmless or less toxic substances by microbial activity.One of the methods of collecting degrading bacteria is from dirt, water and other polluted environment by organophosphorus pesticides. A lot of organophosphorus pesticides are chiral and biological activity between different isomers is very of difference. Chiral material into the ecological environment uptake by microbial, different microbes may selectively absorb metabolism and degradat with different enantiomers of material. Organophosphorus pesticide without invalid enantiomers has small side effects and high efficacy to the environment, and save raw materials. Therefore, study of chiral pesticides environment of behavior, to obtain single highly active enantiomers of pesticides to protect the ecological environment has the cross time significance.In recent years, microbial degradation of organophosphorus pesticide and the chiral resolution of organophosphorus pesticide were reported, but the microorganisms in the degradation of enantiomers level rarely reported.This experiment research significance and the innovation is the combination of microbial degradation, and degradation of chiral, study the microbial degradation of organophosphorus pesticide from the antipode level. The main contents are as follows:1)In this paper,degradation of profenofos and its enantiomer were systemically studied.The half-lives of profenofos were 17.33 h in A soil and 13.86 h in B soil. Further determination of ER found that ER value increased from 1.0 to1.31 in B soilbut almost no changes in A soil.2)Enrich and screen strains: Three kinds of strains are screened out from A soil.Seven days later, the degradation rate were 26.85%, 46.99% and 37.98% respectively. In the process of degradation of profenofos, strains were not selective on enantiomers. A degrading strain was screened from B soil. After 7d, the degradation rate was 52.55% and rising. Compared with the ER value profenofos degrade in soil, single strains need longer time for the degration. It showed that the degradation of profenofos is the result of joint action of various bacteria.3)Identification of strains: Identification of strains: A-1was Preliminarily ideniified as Agrobacterium and A-2 was stenotrop Homonas maltop Hilia and A-3 was Pseudomonas; B-1 was Klebsiella Oxytoca. Among them, B-1 had better degradation effeet for profenofos.4)To optimize the best condition of degradation of profenofos: Choose B-1 as the target strains, The result showed that under the conditions of 30℃, p H of 7.5, the speed of 180r/min, quantity of 5%, the degradation effete was good using the strain when 100mg/l of profenofos.