奥奈达希瓦氏菌（Shewanella oneidensis MR-1）对洛克沙胂生物转化的影响研究

发布时间：2018-02-07 14:22

  本文关键词： 洛克沙胂 S. oneidensis MR-1 生物转化 可溶性Fe(Ⅲ) 含水率　出处：《合肥工业大学》2016年硕士论文　论文类型：学位论文

【摘要】：洛克沙胂作为一种广泛应用的畜禽养殖业饲料添加剂,在动物体内基本不被降解,会随畜禽粪便和养殖废水进入土壤和水环境中,导致潜在的砷污染。希瓦氏菌是一种兼性厌氧菌,在土壤、海洋和其他水体中广泛存在,能在厌氧条件下利用多种电子受体,包括三价铁、硝酸盐、亚硝酸盐和某些重金属离子等,进行产能代谢和电子传递。本论文以洛克沙胂为研究对象,选取模式菌种奥奈达湖希瓦氏菌(Shewanella oneidensis MR-1)作为处理洛克沙胂的手段,分析土壤含水率条件变化对洛克沙胂生物转化的影响,探究S. oneidensis MR-1转化洛克沙胂的机理。主要结论如下：水相厌氧体系中S. oneidensis MR-1对洛克沙胂生物转化的可行性：在水相厌氧环境中,S. oneidensis MR-1可以将洛克沙胂作为最终的电子受体,还原为4-羟基-3-氨基苯胂酸(HAPA),并且HAPA为洛克沙胂生物转化还原后的唯一检出产物;然而在缺乏外源性底物时,洛克沙胂不能直接被S. oneidensis MR-1转化,证明了短期内洛克沙肿无法充当生物转化的可利用的碳源。不同浓度洛克沙肿浓度对S. oneidensis MR-1转化洛克沙胂的影响实验表明洛克沙胂不会抑制S. oneidensis MR-1的生长,反而会促进其生长,起始洛克沙胂浓度越高细菌生长速度越快。水相中可溶性Fe(Ⅲ)的存在对S. oneidensis MR-1生物转化洛克沙胂的影响：在水相厌氧环境中,S. oneidensis MR-1存在的条件下,可溶性Fe(Ⅲ)的出现能够显著的促进S. oneidensis MR-1转化洛克沙胂,同时,加入的可溶性Fe(Ⅲ)在反应中会生成次生铁矿,吸附洛克沙胂转化生成的HAPA,有机胂得到了固定,降低了砷的迁移性；但是高浓度的可溶性Fe(Ⅲ)不仅不能促进S.oneidensis MR-1生物转化洛克沙胂,反而会抑制S. oneidensis MR-1对洛克沙胂生物转化；较低浓度的可溶性Fe(Ⅲ)(2.0mmol/L)就足以促进S. oneidensis MR-1生物转化洛克沙胂,但是由于加入不同浓度可溶性Fe(Ⅲ)生成的次生铁矿量不一样,实验终止时4-羟基-3-氨基苯胂酸(HAPA)被吸附的量也相应的不同。固相多孔介质中不同含水率情形下,S. oneidensis MR-1的胞外聚合物(EPS)分泌量随着含水率水平减小而增加；含水率的变化明显影响S. oneidensis MR-1转化洛克沙胂,只有到达一定含水率水平,足够达到提供S. oneidensis MR-1生长繁殖以及转移电子的水环境,洛克沙胂才能够被S. oneidensis MR-1所转化,同时发现含水率越高,洛克沙胂被转化的效率越高。
[Abstract]:Roxarsone, as a widely used feed additive for livestock and poultry breeding, is basically not degraded in animals and will enter the soil and water environment with animal manure and wastewater. Shiva is a facultative anaerobes that are widespread in soils, oceans and other water bodies and can use a variety of electron receptors in anaerobic conditions, including iron trivalent, nitrate, and so on. Nitrite and some heavy metal ions were used for capacity metabolism and electron transport. In this paper, the model strain Shewanella oneidensis MR-1 was selected as the treatment method of roxarsone. The effects of soil moisture content on roxarsone biotransformation were analyzed. To explore the mechanism of the transformation of roxarsone by S. oneidensis MR-1. The main conclusions are as follows: the feasibility of the biotransformation of roxarsone by S. Oneidensis MR-1 in aqueous anaerobic system: in aqueous anaerobic environment, roxarsone can be used as the final electron receptor by oneidensis MR-1. The product was reduced to 4-hydroxy-3-aminophenylarsonic acid, and HAPA was the only product detected after bioconversion of roxarsone. However, roxarsone could not be directly transformed by S. oneidensis MR-1 in the absence of exogenous substrates. The results showed that roxarsam could not be used as an available carbon source for biotransformation in a short period of time. The effects of roxarsam concentrations on the transformation of roxarsone by S. oneidensis MR-1 showed that roxarsone did not inhibit the growth of S. oneidensis MR-1, but promoted the growth of roxarsone. The higher the initial roxarsone concentration, the faster the bacterial growth rate. The effect of soluble Fe (鈪，

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