论文总字数：29317字

摘 要

嗜酸氧化亚铁硫杆菌（Acidithiobacillus ferrooxidans，简称A. ferrooxidans）是一种应用广泛的生物浸出细菌，在生物冶金过程中发挥非常重要作用。A. ferrooxidans以亚铁、单质硫或硫化物等作为能源，通过氧化亚铁产生氧化剂-Fe³ 或氧化还原态硫生成浸出剂H₂SO₄等代谢产物间接促进重金属溶出，现已被广泛应用于贫/尾矿、工业废渣、电子电器废弃物、城市污泥等含重金属资源回收利用。

本研究以电镀污泥中主要重金属离子作为胁迫因素，考察不同重金属离子对以A. ferrooxidans为主的嗜酸铁氧微生物富集物生长及亚铁氧化代谢性能（亚铁氧化率和胞外电子传递）的影响，揭示电镀污泥浸出液中不同重金属离子对嗜酸铁氧微生物富集物活性的影响规律，并确定A. ferrooxidans亚铁氧化活性半抑制重金属浓度。

实验结果指出：①A. ferrooxidans对四种典型重金属毒性的耐受能力存在显著差异。Cr³ 、Cu² 、Ni² 、Zn² 四种重金属对A. ferrooxidans的抑制作用由强到弱为：Cr³ ＞Cu² ＞Zn² ＞Ni² 。②重金属胁迫浓度越高对A. ferrooxidans生长和亚铁氧化活性抑制作用越显著。高重金属浓度抑制了A. ferrooxidans生长，甚至导致其死亡；A. ferrooxidans亚铁氧化活性半抑制重金属浓度分别约为0.5g/L Cr³ 、15g/L Cu² 、40g/L Zn² 和＞40g/L Ni² 。③循环伏安曲线结果表明，经过驯化后的A. ferrooxidans胞外电子传递能力得到增强，即驯化后A. ferrooxidans在同等Cr³ （0.5g/LCr³ ）胁迫体系中亚铁氧化能力相比于未驯化菌株得到了改善。

综上所述，A. ferrooxidans能够耐受不同重金属胁迫，其中Cr³ 胁迫对其生长和亚铁代谢影响最为显著，但通过连续逐步驯化可以提高A. ferrooxidans最终耐受重金属能力。这一结果对进一步开展嗜酸微生物浸出电镀污泥过程优化及机理研究具有重要意义。

关键词：嗜酸氧化亚铁硫杆菌；生物浸出；重金属胁迫；亚铁氧化活性；胞外电子传递；驯化

Abstract

Acidithiobacillus ferrooxidans (A. ferrooxidans) is a widely used bacterium for bioleaching of minerals and plays an important role in the biometallurgical process. It can use ferrous iron, elemental sulfur, and sulfides as energy sources, and indirectly promote the dissolution of heavy metals by oxidizing ferrous iron to produce oxidant- Fe³ , or oxidizing and reducing sulfur to produce leaching H₂SO₄ and other metabolic products. Now A. ferrooxidans have been widely used in the recycling of heavy metal-containing resources such as low grade ore or tailings, industrial waste residue, electronic and electrical waste, and municipal sludge.

In this dissertation, the effects of different heavy metals (Cu² , Ni² , Cr³ , and Zn² ) on ferrous iron oxidation (ferrous oxidation rate and extracellular electron transport) of A. ferrooxidans were investigated, and the tolerability of A. ferrooxidans to four typically heavy metals was revealed, and determined the ferrous oxidation activity of A. ferrooxidans semi-inhibitory heavy metal concentrations.

The experimental results showed that: firstly, there were significant differences in the tolerance of A. ferrooxidans to the toxicity of four typical heavy metals. The inhibitory effects of Cr³ , Cu² , Ni² , and Zn² on A. ferrooxidans ranged from strong to weak: Cr³ gt;Cu² gt; Zn² gt;Ni² . Secondly, elevated heavy metal stress implies inhibition of A. ferrooxidans growth and ferrous oxidation activity. High concentrations of heavy metals inhibited the growth of A. ferrooxidans and even led to its death; Semi-inhibited heavy metals concentrations about Ferrous oxidation activity of A. ferrooxidans are about 0.5g/L Cr³ 、15g/L Cu² 、40g/L Zn² and ＞40g/L Ni² . Thirdly, by making cyclic voltammograms, it was found that the extracellular electron transport capacity of A. ferrooxidans after acclimation is enhanced, and the ferrous oxidation ability of A. ferrooxidans acclimated by Cr³ in 0.5g/L system was improved compared to normal strains.

In summary, A. ferrooxidans can tolerate different heavy metal stress, in which Cr³ stress has the most significant effect on its growth and ferrous metabolism, but through gradually continuous acclimation, the ability of A. ferrooxidans to endure heavy metals can be improved. This result is of great significance for the further optimization of the process of electroplating sludge from acidophilic microorganisms and the study of its mechanism.

Key words: A. ferrooxidans; Bioleaching; Heavy metal stress; Ferrous oxidation activity; Extracellular electron transport; Domestication

目录

摘要 I

Abstract II

目录 I

第一章 文献综述 - 1 -

1.1 生物冶金 - 1 -

1.2 Acidithiobacillus ferrooxidans等极端嗜酸浸矿微生物 - 1 -

1.3 重金属胁迫对微生物生长及代谢的影响 - 3 -

1.4 Acidithiobacillus ferrooxidans亚铁氧化代谢途径 - 3 -

1.5研究内容、目的及意义 - 4 -

1.6论文资助情况 - 5 -

第二章 实验材料与方法 - 6 -

2.1 概述 - 6 -

2.2 实验材料 - 6 -

2.2.1菌种 - 6 -

2.2.2 试剂 - 6 -

2.2.3 培养基及其条件 - 7 -

2.3 实验仪器 - 8 -

2.4 实验方法 - 9 -

2.4.1 A. ferrooxidans高活性培养 - 9 -

2.4.2 A. ferrooxidans的扩培 - 10 -

2.4.3不同重金属离子胁迫对A. ferrooxidans生长及亚铁氧化性能的影响 - 10 -

2.4.4 A. ferrooxidans菌浓的测定 - 11 -

2.4.5 Fe² 、Fe³ 、总铁测定——邻菲啰啉分光光度法 - 11 -

2.5 A. ferrooxidans耐受Cr³ 驯化及胞外电子传递的研究 - 13 -

第三章 结果与讨论 - 15 -

3.1 不同浓度Cr³ 对A. ferrooxidans生长及亚铁氧化性能的影响 - 15 -

3.1.1 pH、ORP 的变化 - 15 -

3.1.2 Fe² 、总铁、Fe³ 的变化 - 17 -

3.1.3 菌浓的变化 - 20 -

3.2 不同浓度Cu² 对A. ferrooxidans生长及亚铁氧化性能的影响 - 21 -

3.2.1 pH、ORP 的变化 - 21 -

3.2.2 Fe² 、总铁、Fe³ 的变化 - 22 -

3.2.3 菌浓的变化 - 25 -

3.3 不同浓度Zn² 对A. ferrooxidans生长及亚铁氧化性能的影响 - 26 -

3.3.1 pH、ORP 的变化 - 26 -

3.2.2 Fe² 、总铁、Fe³ 的变化 - 27 -

3.3.3 菌浓的变化 - 30 -

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