中间产物在磺胺嘧啶生物降解中的作用

发布时间：2019-05-21 21:19

【摘要】：抗生素是世界上用量最大,使用最广泛的药物之一,欧洲每年抗生素的使用量高达1400多吨,其中大部分用于动物;美国每年抗生素的用量约为17800吨,约70%用于畜牧水产养殖业;全球抗生素年均使用总量约为100000吨~200000吨。近几年我国每年也有成千上万吨的抗生素类药物被用于畜禽养殖业和人的医疗中,我国药物处方中抗生素高达70%,与西方国家相对比,我国抗生素滥用情况严重。本实验所研究的磺胺嘧啶(Sulfadiazine,SD),作为一种重要的抗生素类药物,是临床治疗,畜牧业和水产养殖业中的常用抗菌药物,由嘧啶环和苯环构成。是一种含氮、硫的杂环化合物,是磺胺类药物的代表,属于较难生物降解的化合物。其进入环境后由于诱导耐药菌株的产生而不易生物降解。然而近几年,每年都有大量磺胺嘧啶进入环境系统中,可能长期存留,药物残留对生态系统和人类健康都造成危害,对磺胺类废水的降解研究日益受到重视。目前大多数城市生活污水处理厂均以活性污泥法为主。目前,其主要功能以去除氨氮、TP、COD或BOD为主,缺乏对药物活性组分有效去除的功能。因此,一旦污水处理系统遭遇到类似嘧啶药物组分这类具有对微生物强抑制性成分的排入,轻者导致污水处理效率的下降,重者则导致整个活性污泥系统的崩溃。而采用有效的处理方法缓解磺胺嘧啶药物对微生物的抑制性,加速其在环境水体中的降解速度,以避免对人类自身产生危害具有重要的实际意义。目前的研究发现,针对磺胺类药物废水,化学氧化法处理效率较高,但降解不彻底,还可能生成对环境有不利影响的中间产物。而单一的生物法降解效率低,还往往受到生物抑制导致生物活性下降。而通过紫外光解或光催化方法作为生物方法的预处理,可以明显地提高磺胺药物可生化性,并提高它们的降解速率。本实验借助紫外光解法先对SD进行降解,将降解后的SD与葡萄糖的混合溶液作为微生物生长的C、N源,探讨光解处理后是否能达到缓解SD对微生物的抑制能力。同时,在紫外法加速降解磺胺嘧啶的过程中,分析紫外光照射下的中间产物的生成,在探究SD的光解途经的同时,尤其是在生物降解过程中以中间产物作为内援电子供体,分别采用单独光解、单独生物降解以及光解与生物降解同步耦合的方法对不同浓度的磺胺嘧啶和中间产物进行降解实验,了解其降解规律以及矿化程度。并发现两种主要中间产物对SD的生物降解有着一定规律的抑制或促进作用。结果表明:(1)通过紫外光照(光照强度设定为0.9mW/cm2)初始浓度为20mg/l的磺胺嘧啶(SD),在SD本身进行降解的同时,有两种重要的中间产物生成,分别为对氨基苯磺酸(4-ABS)和二氨基嘧啶(2-AP),且在整个生物降解过程中可以发现,对氨基苯磺酸的生成趋势呈波动状,即在初期为增长的趋势,后期呈下降趋势。二氨基嘧啶则呈现缓慢的低浓度的上升趋势。在磺胺嘧啶(SD)降解的同时,其本身自带的两种离子N离子和S离子也会随之脱离。和实验之前推测的结果相同,N离子以铵根的形式脱除,与此同时S离子也以硫酸根的形式脱除。(2)经过紫外光解后的磺胺嘧啶,生成的中间产物在接下来的生物降解过程中对磺胺嘧啶的生物降解起到了促进降解的作用。通过辩证分析实验,将两种中间产物分别与磺胺嘧啶溶液进行混合后生物降解,从结果可以证明之前的推测,即其中一种主要中间产物二氨基嘧啶在磺胺嘧啶生物降解中产生了抑制的作用,反之,另一种主要中间产物对氨基苯磺酸在磺胺嘧啶生物降解中有着明显的促进作用。也同时证明了,在紫外光照后进行生物反应的实验中,紫外光照产物对氨基苯磺酸是使磺胺嘧啶降解速率明显增加的主要原因。(3)通过提高电子数量可以将磺胺嘧啶的生物降解速率大大提高。当所提供的电子当量想同时,相对应的磺胺嘧啶的降解速率也相同。通过反应期间关于离子变化的测量与分析,可以看出,对氨基苯磺酸在生物降解的过程中并没有释放出S离子,但是却在紫外光解后生物降解磺胺嘧啶的过程中促进了磺胺嘧啶脱硫的速率,使磺胺嘧啶更早的释放出了S离子。而磺胺嘧啶经过紫外光照后生成的两种主要中间产物在其生物降解过程中分别起到了促进和抑制的作用。两种中间产物之间也存在着一定的电子竞争关系。实验结果也可以说明,磺胺嘧啶的生物降解过程中,有效电子起到了作用,但与有效电子的种类无关。综上所述,在紫外光照后磺胺嘧啶的生物降解过程中,产生的中间产物二氨基嘧啶也同时进行生物降解,在此过程中与磺胺嘧啶产生了电子竞争关系,利用生成的另一种中间产物对氨基苯磺酸所提供的电子抢先降解,这也证实了二氨基嘧啶抑制磺胺嘧啶降解的原因。
[Abstract]:Antibiotics are the world's largest and one of the most widely used drugs, and the amount of antibiotics used in Europe is as high as 1400 tons per year, most of which are used in animals; the amount of antibiotics per year in the United States is about 17800 tons and about 70 per cent is used for livestock and aquaculture; The annual average annual use of the global antibiotics is about 100,000 tons to 200,000 tons. In recent years, in our country, thousands of tons of antibiotics are used in the livestock and poultry breeding industry and people's medical treatment. The antibiotics in our country's drug prescription are as high as 70%, compared with the western countries, the abuse of antibiotics in our country is serious. Sulfaadiazine (SD), a kind of important antibiotic medicine, is one of the most important antibiotics in clinical treatment, animal husbandry and aquaculture. Is a heterocyclic compound containing nitrogen and sulfur, and is a compound of sulfanilamide, and belongs to a compound which is difficult to be biodegraded. Which is not easy to be biodegraded due to the production of the induced drug resistant strain after entering the environment. However, in recent years, a large amount of sulfanilamide in the environmental system may remain in the environment for a long time, and the drug residue may be harmful to the ecosystem and human health, and the research on the degradation of the sulfonamides wastewater is becoming more and more important. At present, most of the urban domestic sewage treatment plants are mainly activated sludge process. At present, the main function of the invention is to remove ammonia nitrogen, TP, COD or BOD, and has the function of effectively removing the active components of the medicine. Thus, as soon as the wastewater treatment system encounters a similar fluorocarbon component of this type having a strong inhibitory component to the microorganism, the lighter results in a decrease in the efficiency of the sewage treatment, and the heavy person results in a collapse of the whole activated sludge system. And the effective treatment method is adopted to relieve the inhibitory effect of the sulfanilamide on the micro-organisms and to accelerate the degradation speed of the sulfanilamide to the environment water body so as to avoid the important practical significance to the human self-production hazard. The present study found that for sulfonamides wastewater, the treatment efficiency of the chemical oxidation process is high, but the degradation is not complete, and the intermediate products which have adverse effects on the environment can also be generated. And a single biological method is low in degradation efficiency, and is often subjected to biological inhibition, resulting in a decrease in biological activity. And the degradation rate of the sulfanilamide can be improved obviously by the pretreatment of the biological method by the ultraviolet light solution or the photocatalytic method. In this experiment, SD was first degraded by UV, and the mixed solution of SD and glucose was used as the C and N source of microbial growth. at the same time, in the process of accelerating the degradation of the sulfanilamide by the ultraviolet method, the generation of the intermediate product under the irradiation of the ultraviolet light is analyzed, The degradation experiments of sulfanilamide and intermediate products with different concentrations were carried out by the method of biodegradation and the simultaneous coupling of photolysis and biodegradation, and the degradation and the degree of mineralization were studied. It was found that the two major intermediate products could inhibit or promote the biodegradation of SD. The results showed that: (1) The initial concentration of sulfanilamide (SD) with the initial concentration of 20 mg/ l was set to be 20 mg/ l by UV irradiation (light intensity was set to 0.9 mW/ cm2), and two important intermediate products were produced in SD itself, which were p-aminobenzenesulfonic acid (4-ABS) and diamino-benzenesulfonic acid (2-AP), respectively. And during the whole biodegradation process, the production trend of the p-aminobenzenesulfonic acid is in a wave shape, that is, the trend of the growth in the early stage is the trend of the growth, and the later period is in a downward trend. The diaminopterin presents a slow, low concentration of the upward trend. At the same time of the degradation of the sulfanilamide (SD), the ion and the S-ion of the two ions are also separated from each other. And the S-ions are also removed in the form of sulfate. (2) the prepared intermediate product has the effect of promoting the degradation of the sulfanilamide peroxide in the subsequent biodegradation process through the sulfanilamide peroxide solution after the ultraviolet light solution. According to the dialectical analysis experiment, the two intermediate products are respectively mixed with the sulfanilamide peroxide solution to be biodegraded, and the result can be proved that one of the main intermediate products, the diaminopterin, has the effect of inhibition in the biodegradation of the sulfanilamide, and vice versa, The other major intermediate product has a significant effect on the biodegradation of the sulfanilamide in the sulfanilamide. It is also proved that in the experiments of the biological reaction after the ultraviolet irradiation, the UV-light product is the main cause of the apparent increase of the degradation rate of the sulfanilamide. (3) The rate of biodegradation of the sulfanilamide peroxide can be greatly improved by increasing the number of electrons. The rate of degradation of the corresponding sulfanilamide is also the same when the supplied electron equivalent is desired. Through the measurement and analysis of the ion change during the reaction, it can be seen that the p-aminobenzenesulfonic acid does not release the S ions in the process of biodegradation, but the rate of the sulfanilamide peroxide desulfurization is promoted in the process of degrading the sulfanilamide peroxide after the ultraviolet light is released, And the sulfanilamide is released to release the S ions earlier. In the process of biodegradation, the two main intermediates produced by the ultraviolet irradiation of the sulfanilamide have the effects of promoting and inhibiting. There is also a certain electronic competitive relationship between the two intermediate products. The experimental results also show that the effective electrons play an important role in the process of biodegradation of sulfanilamide, but not related to the species of active electrons. In conclusion, in the process of the biodegradation of the sulfanilamide peroxide after the ultraviolet irradiation, the intermediate product diaminopterin is also biodegraded at the same time, and the electronic competitive relationship with the sulfanilamide peroxide is generated in the process, The use of the resulting further intermediate product for the pre-emptive degradation of the p-aminobenzenesulfonic acid also confirmed the reason for the diamino-benzenesulfonic acid to inhibit the degradation of the sulfanilamide.
【学位授予单位】：上海师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X703

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