有機(jī)磷農(nóng)藥微生物手性降解的研究
發(fā)布時間：2018-10-19 07:49
【摘要】：有機(jī)磷農(nóng)藥一方面給農(nóng)民和農(nóng)業(yè)帶了巨大的經(jīng)濟(jì)效益,另一方面也給土壤、大氣和水等環(huán)境帶來了嚴(yán)重的污染,對人類健康造成了很大威脅。因此,研究有機(jī)磷農(nóng)藥的降解具有很大的現(xiàn)實意義。有機(jī)磷農(nóng)藥降解方法目前主要有光化學(xué)降解、化學(xué)降解、生物降解等方式,其中生物降解以其高效、徹底、無二次污染的優(yōu)勢占據(jù)了重要地位。主要是通過微生物的作用將環(huán)境中的有機(jī)污染物轉(zhuǎn)化為CO2和H2O等無毒、無害或毒性較小的物質(zhì)。從污泥、水體等受農(nóng)藥污染的環(huán)境中篩選是獲取降解菌的主要途徑之一。很多有機(jī)磷農(nóng)藥都具有手性且不同的異構(gòu)體之間生物活性差異很大。手性物質(zhì)進(jìn)入生態(tài)環(huán)境被微生物攝取后,不同的微生物可能選擇性的攝取、代謝和降解同一手性物質(zhì)的不同對映體。不含無效對映體的有機(jī)磷農(nóng)藥對環(huán)境副作用小、藥效高甚至節(jié)省原料。因此,研究手性農(nóng)藥對映體選擇性環(huán)境的行為,獲取單一高活性對映體農(nóng)藥對保護(hù)生態(tài)環(huán)境具有跨時代的意義。近年來,有機(jī)磷農(nóng)藥的微生物降解和有機(jī)磷農(nóng)藥的手性拆分均有報道,但微生物在對映體水平上的降解鮮有報道。本實驗研究有機(jī)磷農(nóng)藥微生物手性降解其意義及創(chuàng)新之處就在于二者的結(jié)合,從對映體層面研究微生物對有機(jī)磷農(nóng)藥的降解。本文的研究內(nèi)容如下:(1)系統(tǒng)的研究了丙溴磷在A、B兩種土壤中外消旋體及對映體選擇性降解情況。A、B兩種土壤中丙溴磷的降解半衰期分別為17.33h、13.86h,進(jìn)一步手性測定發(fā)現(xiàn),A土中ER值幾乎沒變化;B土中ER值從1.0升高到1.31。(2)菌株的富集與篩選:從A土中篩選出三種菌株培養(yǎng)至7d時,降解率分別為26.85%、46.99%、37.98%。三種菌株在降解丙溴磷過程中對對映體均沒有選擇性。從B土中篩選出一種降解菌,培養(yǎng)至7d時,降解率為52.55%且ER值有所升高。單一菌株對丙溴磷的降解時間都比較長,這表明土壤中丙溴磷的降解是多種微生物共同作用的結(jié)果。(3)對獲取的菌株進(jìn)行種屬鑒定:經(jīng)鑒定A-1為土壤桿菌屬Agrobacterium,A-2為寡養(yǎng)單胞菌stenotropHomonas maltopHilia,A-3為綠膿桿菌Pseudomonas;B-1產(chǎn)酸克雷伯菌Klebsiella Oxytoca(4)優(yōu)化影響該菌降解率的最佳條件:選擇B-1為目標(biāo)菌株對丙溴磷降解條件進(jìn)行優(yōu)化,表明在30℃、pH=7.5、轉(zhuǎn)速180r/min、接種量5%時最有利于100mg/L丙溴磷降解。
[Abstract]:On the one hand, organophosphorus pesticides bring great economic benefits to farmers and agriculture, on the other hand, they also bring serious pollution to the environment such as soil, atmosphere and water, which pose a great threat to human health. Therefore, it is of great practical significance to study the degradation of organophosphorus pesticides. At present, the main degradation methods of organophosphorus pesticides are photochemical degradation and biodegradation, among which biodegradation occupies an important position because of its high efficiency, thoroughness and no secondary pollution. The organic pollutants in the environment are mainly transformed into non-toxic, harmless or less toxic substances such as CO2 and H2O through the action of microbes. It is one of the main ways to obtain biodegradable bacteria from the environment polluted by pesticides such as sludge and water. Many organophosphorus pesticides have chiral properties and differ in bioactivity among different isomers. When chiral substances enter the ecological environment, different microbes may selectively ingest, metabolize and degrade different enantiomers of the same chiral substances. Organophosphorus pesticides without invalid enantiomers have little environmental side effects, high efficacy and even saving raw materials. Therefore, the study of enantioselective behavior of chiral pesticides and the acquisition of single highly active enantiomers have a cross-epoch significance for the protection of the ecological environment. In recent years, microbial degradation of organophosphorus pesticides and chiral resolution of organophosphorus pesticides have been reported, but microbial degradation at enantiomeric level is rarely reported. In this study, the significance and innovation of chiral degradation of organophosphorus pesticide (OPP) by microorganism was studied by the combination of them, and the biodegradation of organophosphorus pesticide by microorganism was studied at enantiomeric level. The main contents of this paper are as follows: (1) the selective degradation of propylophosphorus in two kinds of soils was systematically studied. The degradation half-life of propranophosphorus was 17.33 h and 13.86 h, respectively. The value of ER in soil was almost unchanged, the value of ER in soil B increased from 1.0 to 1.31. (2) the enrichment and screening of strains: three strains were screened from soil A for 7 days. The degradation rates were 26.85 and 46.99, respectively. The three strains showed no enantioselectivity in the degradation of propyl bromide. A biodegradable bacterium was screened from B soil, and the degradation rate was 52.55% and the ER value was increased when cultured for 7 days. The degradation time of propyl bromide by single strain was relatively long. The results showed that the degradation of propranophos in soil was the result of the interaction of many microbes. (3) species identification of the obtained strains: A-1 was identified as Agrobacterium Agrobacterium,A-2 and stenotropHomonas maltopHilia,A-3 as Klebsiella aeruginosa Pseudomonas;B-1. Klebsiella Oxytoca (4) the optimal conditions for the degradation of Propirophos were optimized by selecting B-1 as the target strain, and selecting B-1 as the target strain. The results showed that at 30 鈩，
本文編號：2280563
[Abstract]:On the one hand, organophosphorus pesticides bring great economic benefits to farmers and agriculture, on the other hand, they also bring serious pollution to the environment such as soil, atmosphere and water, which pose a great threat to human health. Therefore, it is of great practical significance to study the degradation of organophosphorus pesticides. At present, the main degradation methods of organophosphorus pesticides are photochemical degradation and biodegradation, among which biodegradation occupies an important position because of its high efficiency, thoroughness and no secondary pollution. The organic pollutants in the environment are mainly transformed into non-toxic, harmless or less toxic substances such as CO2 and H2O through the action of microbes. It is one of the main ways to obtain biodegradable bacteria from the environment polluted by pesticides such as sludge and water. Many organophosphorus pesticides have chiral properties and differ in bioactivity among different isomers. When chiral substances enter the ecological environment, different microbes may selectively ingest, metabolize and degrade different enantiomers of the same chiral substances. Organophosphorus pesticides without invalid enantiomers have little environmental side effects, high efficacy and even saving raw materials. Therefore, the study of enantioselective behavior of chiral pesticides and the acquisition of single highly active enantiomers have a cross-epoch significance for the protection of the ecological environment. In recent years, microbial degradation of organophosphorus pesticides and chiral resolution of organophosphorus pesticides have been reported, but microbial degradation at enantiomeric level is rarely reported. In this study, the significance and innovation of chiral degradation of organophosphorus pesticide (OPP) by microorganism was studied by the combination of them, and the biodegradation of organophosphorus pesticide by microorganism was studied at enantiomeric level. The main contents of this paper are as follows: (1) the selective degradation of propylophosphorus in two kinds of soils was systematically studied. The degradation half-life of propranophosphorus was 17.33 h and 13.86 h, respectively. The value of ER in soil was almost unchanged, the value of ER in soil B increased from 1.0 to 1.31. (2) the enrichment and screening of strains: three strains were screened from soil A for 7 days. The degradation rates were 26.85 and 46.99, respectively. The three strains showed no enantioselectivity in the degradation of propyl bromide. A biodegradable bacterium was screened from B soil, and the degradation rate was 52.55% and the ER value was increased when cultured for 7 days. The degradation time of propyl bromide by single strain was relatively long. The results showed that the degradation of propranophos in soil was the result of the interaction of many microbes. (3) species identification of the obtained strains: A-1 was identified as Agrobacterium Agrobacterium,A-2 and stenotropHomonas maltopHilia,A-3 as Klebsiella aeruginosa Pseudomonas;B-1. Klebsiella Oxytoca (4) the optimal conditions for the degradation of Propirophos were optimized by selecting B-1 as the target strain, and selecting B-1 as the target strain. The results showed that at 30 鈩，
本文編號：2280563
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