苍白杆菌PW降解芘的强化研究及其下游代谢途径的初步分析

发布时间：2018-03-01 00:22

本文关键词： 苍白杆菌PW 共代谢 Tween80 TPPB 代谢途径　出处：《北京化工大学》2015年硕士论文　论文类型：学位论文

【摘要】：多环芳烃(Polycyclic Aromatic Hydrocarbons, PAHs)是一类广泛存在于土壤、水环境等自然环境中的有机污染物,其主要是由煤、石油、天然气等含碳化合物不完全燃烧产生的。由于多环芳烃具有“三致”的危害效应、化学结构稳定而难以被降解以及脂溶性高而易通过食物链进入人体积累等特点易于对生态环境产生危害,并对人体健康产生潜在的威胁,因此,对于多环芳烃污染修复的研究亟待进行。本文以芘(Pyrene)为研究对象,以本实验室从北京焦化厂多环芳烃污染土壤筛选得到的一株芘的高效降解菌苍白杆菌PW(Ochrobactrum sp. PW)为菌株,研究了共代谢对苍白杆菌PW降解芘的影响,并对无机盐液体培养基(MSM)的部分成分作了单因子试验,探讨了表面活性剂以及两相分配生物反应器(TPPB)应用于多环芳烃微生物修复的可行性,并初步分析了苍白杆菌PW降解芘的下游途径,主要研究结果如下：(1)选取胰蛋白胨、酵母浸粉、麦芽糖和醋酸钠分别作为外加碳源,其中酵母浸粉对促进苍白杆菌PW降解芘的效果最显著。以酵母浸粉作为外加碳源,其浓度为50 mg/L时能够促进芘的降解,但当其浓度超过100mg/L时,反而会抑制芘的降解；将MSM培养基中的FeSO4浓度由1 mg/L变为2 mg/L,能够促进芘的降解,而改变(NH4)2SO4和K2HPO4的则会抑制芘的降解。(2) Tween80能够显著增加芘在水中的溶解度,且芘的溶解度随着Tween80的浓度提高而增加；Tween80能够提高苍白杆菌PW对芘的利用效率,促进芘的降解,如Tween80浓度分别为100 mg/L和250 mg/L,芘的浓度为100 mg/L时,芘在第5-8 d的降解率分别为80.3%-91.1%和88.6%-93.5%,高于对照组的73.3%-92.5%。但当Tween80浓度过高时,其反而会抑制芘的降解,且芘浓度越高,Tween80对芘的降解的促进效果越差。(3) TPPB技术对苍白杆菌PW降解芘具有一定的促进作用。TPPB技术对芘降解的影响受到有机相的种类、有机相的比例、芘浓度以及液体扰动速率等因素的影响。液体扰动速率的增加,能够增加水相与有机相之间的接触面积以及芘在两相之间的传质速率,从而促进芘的降解；对于同一种有机相,在芘的浓度较高时,适当提高有机相的比例能够促进芘的降解,如芘的初始浓度为1000 mg/L,有机相比例为2.5%-20%时,水-十六烷体系中芘的降解率分别为24.3%-44.3%,水-十八烷体系中芘的降解率分别为22.6%-48.8%,反之,当芘的浓度较低时,应降低有机相的比例。(4)苍白杆菌PW降解芘的下游途径有两条,一条为邻苯二甲酸途径,另外一条为水杨酸途径,在水杨酸途径中,水杨酸并未被降解为邻苯二酚,而是通过其它途径进入三羧酸循环。
[Abstract]:Polycyclic Aromatic hydrocarbons (PAHs) are a class of organic pollutants in the natural environment, such as soil, water environment and so on. Because polycyclic aromatic hydrocarbons (PAHs) have a "triple-induced" hazard effect, The chemical structure is stable and difficult to degrade, and the characteristics of high liposolubility and easy accumulation through the food chain are easy to harm the ecological environment and pose a potential threat to human health. It is urgent to study the remediation of polycyclic aromatic hydrocarbons (PAHs) pollution. In this paper, Pyrene Pyrene was used as the research object, and a pyrene degrading bacterium, PW(Ochrobactrum sp. PWS, was selected from PAHs contaminated soil of Beijing Coking Plant in our laboratory. The effect of co-metabolism on PW degradation of pyrene by Bacillus pallidus was studied. The feasibility of the application of surfactant and TPPBin in microbial remediation of polycyclic aromatic hydrocarbons (PAHs) was discussed. The downstream pathway of PW degradation of pyrene by P. pallidus was preliminarily analyzed. The main results were as follows: 1) tryptone was selected. Yeast extract powder, maltose and sodium acetate were respectively used as additional carbon sources, among which yeast extract powder had the most significant effect on promoting PW degradation of pyrene. Yeast extract powder could promote pyrene degradation when the concentration of yeast extract powder was 50 mg/L. But when the concentration was over 100mg / L, the degradation of pyrene was inhibited, and the concentration of FeSO4 in MSM medium was changed from 1 mg/L to 2 mg / L, which could promote the degradation of pyrene. However, changing NH _ 4H _ 2SO _ 4 and K _ 2HPO _ 4 could inhibit the degradation of pyrene. Tween80 could significantly increase the solubility of pyrene in water, and the solubility of pyrene increased with the increase of Tween80 concentration. Tween80 could increase the utilization efficiency of pyrene and promote the degradation of pyrene by PW. If the concentration of Tween80 was 100 mg/L and 250 mg / L, and the concentration of pyrene was 100 mg/L, the degradation rates of pyrene were 80.3% -91.1% and 88.6-93.5% at 5-8 days, respectively, which were higher than those of the control group (73.3 -92.5%). However, when the concentration of Tween80 was too high, the degradation of pyrene was inhibited. The higher the concentration of pyrene is, the worse the effect of Tween80 on the degradation of pyrene is. The TPPB technique can promote the degradation of pyrene by PW. The effect of Tween80 on the degradation of pyrene is affected by the kinds of organic phase and the proportion of organic phase. The increase of liquid disturbance rate can increase the contact area between water phase and organic phase and the mass transfer rate of pyrene between two phases, thus promoting the degradation of pyrene. When the concentration of pyrene is high, increasing the proportion of organic phase can promote the degradation of pyrene, such as when the initial concentration of pyrene is 1000 mg / L, the proportion of organic phase is 2.5-20%, The degradation rates of pyrene in water-cetane system were 24.3-44.3 and 22.6-48.8 in water-cetane system, respectively. On the contrary, when the concentration of pyrene was low, the proportion of organic phase should be reduced. One is the phthalic acid pathway, the other is the salicylic acid pathway. In the salicylic acid pathway, salicylic acid is not degraded to catechol, but enters the tricarboxylic acid cycle through other channels.
【学位授予单位】：北京化工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X172;X592

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