有机磷农药微生物手性降解的研究
发布时间：2018-10-19 07:49
【摘要】：有机磷农药一方面给农民和农业带了巨大的经济效益,另一方面也给土壤、大气和水等环境带来了严重的污染,对人类健康造成了很大威胁。因此,研究有机磷农药的降解具有很大的现实意义。有机磷农药降解方法目前主要有光化学降解、化学降解、生物降解等方式,其中生物降解以其高效、彻底、无二次污染的优势占据了重要地位。主要是通过微生物的作用将环境中的有机污染物转化为CO2和H2O等无毒、无害或毒性较小的物质。从污泥、水体等受农药污染的环境中筛选是获取降解菌的主要途径之一。很多有机磷农药都具有手性且不同的异构体之间生物活性差异很大。手性物质进入生态环境被微生物摄取后,不同的微生物可能选择性的摄取、代谢和降解同一手性物质的不同对映体。不含无效对映体的有机磷农药对环境副作用小、药效高甚至节省原料。因此,研究手性农药对映体选择性环境的行为,获取单一高活性对映体农药对保护生态环境具有跨时代的意义。近年来,有机磷农药的微生物降解和有机磷农药的手性拆分均有报道,但微生物在对映体水平上的降解鲜有报道。本实验研究有机磷农药微生物手性降解其意义及创新之处就在于二者的结合,从对映体层面研究微生物对有机磷农药的降解。本文的研究内容如下:(1)系统的研究了丙溴磷在A、B两种土壤中外消旋体及对映体选择性降解情况。A、B两种土壤中丙溴磷的降解半衰期分别为17.33h、13.86h,进一步手性测定发现,A土中ER值几乎没变化;B土中ER值从1.0升高到1.31。(2)菌株的富集与筛选:从A土中筛选出三种菌株培养至7d时,降解率分别为26.85%、46.99%、37.98%。三种菌株在降解丙溴磷过程中对对映体均没有选择性。从B土中筛选出一种降解菌,培养至7d时,降解率为52.55%且ER值有所升高。单一菌株对丙溴磷的降解时间都比较长,这表明土壤中丙溴磷的降解是多种微生物共同作用的结果。(3)对获取的菌株进行种属鉴定:经鉴定A-1为土壤杆菌属Agrobacterium,A-2为寡养单胞菌stenotropHomonas maltopHilia,A-3为绿脓杆菌Pseudomonas;B-1产酸克雷伯菌Klebsiella Oxytoca(4)优化影响该菌降解率的最佳条件:选择B-1为目标菌株对丙溴磷降解条件进行优化,表明在30℃、pH=7.5、转速180r/min、接种量5%时最有利于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，
本文编号：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，
本文编号：2280563
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