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1、安徽农业大学 硕士学位论文 奥奈达希瓦氏菌MR-1的Fe()还原特性及其影响因素研究 姓名：陈洁 申请学位级别：硕士 专业：环境工程 指导教师：储茵;司友斌 2011-06 I 摘 要 异化铁还原是一种微生物代谢过程， 在该过程中微生物以胞外不溶性铁氧化物为 末端电子受体，通过氧化电子供体耦联 Fe()还原。异化铁还原能够降低有毒重金属 毒性，促进芳香烃、卤代芳香烃等有机污染物的降解，同时也促进一些染料化合物降 解，抑制厌氧环境中甲烷的产生。单宁酸和焦性没食子酸可与铁络合生成络合物，增 大铁氧化物的溶解性，从而促进 Fe()还原。奥奈达希瓦氏菌 MR-1（Shewanclla oneidens
2、is MR-1）既可以在有氧环境也可以在厌氧环境下生长，不仅能生物修复卤化 有机污染物，而且也能够还原和溶解某些难溶性的金属氧化物。本文选用该菌株为研 究对象，研究不同因素对 Fe()异化还原的影响，并探讨添加有机酸络合剂对提高水 稻土中 Fe()还原的作用。主要的研究内容和结果如下； 1. 奥奈达希瓦氏菌MR-1的Fe()还原特性： 以乙酸盐、 乳酸盐和丙酮酸盐作为Fe() 还原的唯一电子供体，Fe()还原率分别达到 39.12%、50.89%和 44.98%；以 FeCl3、 Fe(OH)3和柠檬酸铁这三种溶解度不同的 Fe()为菌株 MR-1 的唯一电子受体， Fe() 还原率分别达到
3、44.72%、51.54%和 10.45%；一定浓度的溶解氧对菌株 MR-1 的异化 铁还原有一定的抑制作用；菌株 MR-1 可在 pH 5.09.0 范围内对 Fe()进行还原； 利用不同的蛋白质变性剂 SDS 和 OGP 证明菌株 MR-1 的 Fe()还原功能蛋白主要集 中在细胞外膜。 2. 络合剂对奥奈达希瓦氏菌 MR-1 还原 Fe()的影响。 结果表明： 在电子供体充足的 条件下，随着络合剂添加浓度的增加，菌株的 Fe()还原率增加；在单宁酸和焦性没 食子酸投加浓度分别为 5 mmol L-1和 10 mmol L-1时，最高铁还原率达到 57.07%、 64.30%和 44.60
4、%、48.35%；反应后期铁还原率有所下降。 3. 添加不同有机酸络合剂对水稻土中 Fe(III)还原的影响。结果表明：铁还原率随着 络合剂添加浓度的增加而增大，在三种土壤中的 Fe(II)生成量是砂姜黑土黄褐土红 壤；在土壤微生物群落实验中，红壤在第 3 天达到最高铁还原率，后期因为环境 pH 值的下降致使铁还原率下降；黄褐土在反应初期铁还原率较稳定，后期显著增大；砂 姜黑土中的微生物群落对 Fe(III)还原效率最高；在土壤泥浆实验中，添加络合剂明显 加快水稻土中 Fe(III)还原速率，Fe(II)生成量较对照显著提高，反应后期 Fe(II)生成量 渐趋稳定。 灭菌后水稻土中添加有机酸络
5、合剂对 S. oneidensis MR-1 还原 Fe()的影响。结 果表明：土壤浸提液中缺少该菌株还原 Fe()的有效电子供体，当添加该菌株还原 Fe()的优势电子供体时，红壤、黄褐土和砂浆黑土浸提液中的铁还原率为 5.14%、 8.95%和 9.18%，添加单宁酸后铁还原率升高至 8.59%、24.05%和 37.99%；土壤泥浆 II 试验中，红壤中 Fe(II)的生成量几乎没有变化，黄褐土和砂姜黑土中 Fe(II)的生成量 得到了显著提高，且砂浆黑土黄褐土。 关键词：关键词：奥奈达希瓦氏菌 MR-1；Fe()还原；土壤；单宁酸；焦性没食子酸 III Abstract Dissimil
6、atory Iron Reduction (DIR), a process of microbial metabolism, and in this process the microorganism use the insoluble iron oxides which extracellular microorganisms as terminal electron acceptor to oxidated the electron donor, by coupled with Fe () for reduction, in paddy soil, DIR can reduce the t
7、oxicity of toxic heavy metal, aromatic hydrocarbons, some organic pollutants halogenated aromatics and some dye compounds, inhibit the production of methane. The tannic acid and pyrogallic aicd can increase the solubility of iron oxide by generated complex compound with Fe(), thus promoting Fe() red
8、uction. The strains of S.oneidensis MR-1 can grow both in the aerobic environment and the anaerobic conditions, not only can bioremediate the halogenated organic pollutants, but also can restore and dissolve some insoluble metal oxides. This paper selects the strain as the research object, studied t
9、he effects of different factors on the Fe() reduction rate of S. oneidensis MR-1 by adding the complexing agent in paddy soil. The main research contents and results are as follows: 1. Characteristics of iron reducetion of Shewanclla oneidensis MR-1: the iron reduction rates were 39.12%, 50.89% and
10、44.98% using the acetate, lactate and pyruvate as the sole electronic donor of strain MR-1, respectively. The forms of Fe() could influence their reduction, and iron reduction rates were 44.72%, 51.54% and 10.45% using ferric trichloride, ferric hydroxide and ferric citrate as the sole electronic re
11、ceptor of strain MR-1, respectively. Dissolved oxygen inhibited the dissimilatory iron reduction. Strain MR-1 could reduce Fe() in the range of pH 5.0 to 9.0. The effects of protein denatumts SDS and OGP suggested that Fe() reduction function proteins of the strains were mainly localized to the solu
12、ble outer membrane fraction. 2. Effects of dissimilatory iron reduction on the S. oneidensis MR-1 by complexing agent. The results showed that: in the conditions of sufficient electron donor, the Fe () reduction rate of the strains increased with the increase of concentration of complexing agent.Whe
13、n the concentration of tannic acid and pyrogallic aicd is 5 mmol L-1 and 10 mmol L-1, the maximum iron reduction rate is 57.07%, 64.30% and 44.60%, 48.35%, the pH decline in the system caused the decline of iron reduction in later period. 3. Effects of Fe(III) reduction by adding different complexin
14、g agents in the paddy soil. The results showed that: the iron reduction rate improved by increasing the concentration of IV complexing agent, the Fe(II) accumulation is the alfisolvertisolred soil; in the co-culture incubation, the iron reduction rate of red soil reach the hightest in the three days
15、, because of the conditions of the pH increased later but the iron reduction rate has dropped because of the decline of pH value in the late; vertisol in response to the initial iron reduction rate is more stable, acquired a significant increase in later period; the reduction rate of alfisol is the
16、most effective; in the soil slurry, the complexing agent in the paddy soils have accelerated Fe(III) reduction rate initially, and the Fe(II) accumulation improved significantly compared to the control. 4. Effecs of Fe(III) reduction by adding complexing agents on S.oneidensis MR-1 in sterilized paddy soil. The results show that: there is not effective electron donor to reduce Fe(
