Metal sulfide semiconductor electrochemical mechanisms induced by bacterial activity
Metal sulfide semiconductor electrochemical mechanisms induced by bacterial activity
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DOI：
10.1016/s0013-4686(00)00623-x
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发表时间：
2000-10
影响因子：
6.6
通讯作者：
H. Tributsch;J. Rojas-Chapana
中科院分区：
文献类型：
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作者：
H. Tributsch;J. Rojas-Chapana
各种细菌物种（例如，硫杆菌属（Thiobacilli）、纤梭菌属（Leptobacillum））已经适应于利用固体无机半导体硫化物（例如，FeS 2、ZnS、CuFeS 2）作为它们用于二氧化碳固定的能量源。它们所应用的界面电化学机制对于矿物的生物沥滤、酸性矿山污染、钢的生物腐蚀以及基于细菌能量循环的太阳能化学合成具有实际意义。硫化物表面上的细菌攻击是基于使用可回收的化学物质（H+、Fe 2+、硫醇化合物），其破坏硫化物界面中的化学键，从而诱导崩解。100 nm薄的合成FeS 2层进行的模型实验允许细菌细胞和黄铁矿界面之间的相互作用的详细研究。氧化亚铁硫杆菌使用有机多糖层通过基于半胱氨酸的载体分子以胶体形式提取硫。详细分析了细菌尺寸导致蚀坑形成的机理。发现添加表面活性剂诱导细菌细胞的局部浸出活性增加。半胱氨酸的添加刺激细菌活性，并且即使在不存在细菌的情况下也充当硫化物溶解剂。基于硫醇化学鉴定了阻断细菌攻击的机制。发现氧化亚铁纤梭菌采用不同的策略。它只能存在于Fe 2+氧化和溶解FeS 2通过推动-通过一个非常积极的Fe 2 +/3+氧化还原电位，产生在有机胶囊-半导体向电化学溶解电位。因此，FeS 2界面分解成小碎片，从中利用用于Fe 3+还原的电子自由能。两种具有相似电子结构的同构材料FeS 2作为T. ferrooxidans和RuS 2，不能在所有被氧化，进行了详细的比较，以了解细菌诱导的半导体电化学的分子方面。
Various bacterial species (e.g. Thiobacilli, Leptospirillum) have adapted to utilize solid inorganic semiconducting sulfides (e.g. FeS2, ZnS, CuFeS2) as their energy source for carbon dioxide fixation. The interfacial electrochemical mechanisms which they apply have practical relevance for bioleaching of minerals, acid mine pollution, for the biocorrosion of steel, and for solar powered chemosynthesis based on the bacterial energy cycle. The bacterial attack on the sulfide surface is based on the use of recyclable chemical species (H+, Fe2+, thiol-compound) which disrupt chemical bonds in the sulfide interface and thereby induce disintegration. Model experiments performed with 100-nm thin synthetic FeS2layers allowed a detailed study of the interaction between bacterial cells and the pyrite interface. Thiobacillus ferrooxidans uses an organic polysaccharide layer to extract sulfur in the form of colloids via a cysteine-based carrier molecule. The mechanism which leads to corrosion pit formation of bacterial size could be analyzed in great detail. Addition of a surface active agent was found to induce increasingly localized leaching activity of bacterial cells. Addition of cysteine stimulates bacterial activity and acts as a sulfide dissolving agent even in the absence of bacteria. Mechanisms to block bacterial attack were identified on the basis of thiol chemistry. Leptospirillum ferrooxidans was found to apply a different strategy. It can only exist on Fe2+oxidation and dissolves FeS2by pushing — via a very positive Fe2+/3+redox potential, generated within the organic capsula — the semiconductor towards the electrochemical dissolution potential. The FeS2interface thus disintegrates into small fragments from which free energy of electrons for Fe3+reduction is utilized. Two isostructural materials with analogous electronic structure, FeS2which serves as energy source for T. ferrooxidans and RuS2which cannot at all be oxidized, are compared in detail to understand the molecular aspects of bacteria-induced semiconductor electrochemistry.