Extracellular polymeric substances mediate bioleaching/biocorrosion via interfacial processes involving iron(III) ions and acidophilic bacteria
Extracellular polymeric substances mediate bioleaching/biocorrosion via interfacial processes involving iron(III) ions and acidophilic bacteria
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DOI：
10.1016/j.resmic.2005.07.012
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发表时间：
2006-01-01
影响因子：
2.6
通讯作者：
Gehrke, T
中科院分区：
文献类型：
--
作者：
Sand, W;Gehrke, T
胞外聚合物在金属的生物腐蚀、生物浸出、金属硫化物的生物腐蚀以及酸性岩石排水中起着关键作用。为了更好地控制这两个过程，腐蚀或浸出细菌的胞外聚合物的结构和功能至关重要。我们的研究集中在极端嗜热菌Acidithiobacillus ferrooxidans和Leptocellum ferrooxidans，因为这些细菌与它们的底物/基质和它们的环境的相互作用的“简单性”和知识。为此，分析了相应的胞外聚合物的组成及其功能。这两个物种的胞外聚合物主要由中性糖和脂质组成。外聚合物的功能似乎是：（i）介导附着到（金属）硫化物表面，和（ii）通过糖醛酸或矿物表面的其他残留物络合来浓缩铁（III）离子，从而允许对硫化物的氧化攻击。因此，金属硫化物的溶解增强，这可导致生物浸提过程比化学浸提加速20至100倍。进行了实验，以阐明铁（III）离子络合的胞外聚合物的菌株特异性的氧化活性的黄铁矿的差异的重要性。株供试菌在其胞外聚合物中具有大量铁（III）离子的氧化亚铁酶比具有较少铁（III）离子的氧化亚铁酶具有更大的氧化活性。这些数据提供了对细胞外聚合物物质提供给细菌的功能和因此的优势的洞察。将讨论在空间站条件下附着的细胞外聚合物的作用以及由此产生的生物污染，生物腐蚀，恶臭气体等影响。(C)2005年，Elsevier SAS。All rights reserved.
Extracellular polymeric substances seem to play a pivotal role in biocorrosion of metals and bioleaching, biocorrosion of metal sulfides for the winning of precious metals as well as acid rock drainage. For better control of both processes, the structure and function of extracellular polymeric substances of corrosion-causing or leaching bacteria are of crucial importance. Our research focused on the extremophilic bacteria Acidithiobacillus ferrooxidans and Leptospirillum ferrooxidans, because of the "simplicity" and knowledge about the interactions of these bacteria with their substrate/substratum and their environment. For this purpose, the composition of the corresponding extracellular polymeric substances and their functions were analyzed. The extracellular polymeric substances of both species consist mainly of neutral sugars and lipids. The functions of the exopolymers seem to be: (i) to mediate attachment to a (metal) sulfide surface, and (ii) to concentrate iron(III) ions by complexation through uronic acids or other residues at the mineral surface, thus, allowing an oxidative attack on the sulfide. Consequently, dissolution of the metal sulfide is enhanced, which may result in an acceleration of 20- to 100-fold of the bioleaching process over chemical leaching. Experiments were performed to elucidate the importance of the iron(III) ions complexed by extracellular polymeric substances for strain-specific differences in oxidative activity for pyrite. Strains of A. ferrooxidans with a high amount of iron(III) ions in their extracellular polymeric substances possess greater oxidation activity than those with fewer iron(III) ions. These data provide insight into the function of and consequently the advantages that extracellular polymeric substances provide to bacteria. The role of extracellular polymeric substances for attachment under the conditions of a space station and resulting effects like biofouling, biocorrosion, malodorous gases, etc. will be discussed. (C) 2005 Elsevier SAS. All rights reserved.