Center for Microbial Ecology and Technology (CMET), Ghent University, Coupure Links 653, Ghent 9000, Belgium.
FEMS Microbiol Ecol. 2019 Feb 1;95(2). doi: 10.1093/femsec/fiy222.
Sporomusa sphaeroides related strains are to date the only homoacetogens known to increase metallic iron corrosion. The goal of this work was to isolate additional homoacetogenic bacteria capable of using Fe(0) as electron donor and to explore their extracellular electron transfer mechanism. Enrichments were started from anoxic corrosion products and yielded Acetobacterium as main homoacetogenic genus. Isolations were performed with a new procedure using plates with a Fe(0) powder top layer. An Acetobacterium strain, closely related to A. malicum and A. wieringae, was isolated, in addition to a S. sphaeroides strain. The Acetobacterium isolate significantly increased Fe(0) corrosion ((1.44 ± 0.16)-fold) compared to abiotic controls. The increase of corrosion by type strains ranged from (1.28 ± 0.13)-fold for A. woodii to (2.03 ± 0.22)-fold for S. sphaeroides. Hydrogen mediated the electron uptake from Fe(0) by the acetogenic isolates and tested type strains. Exchange of the medium and SEM imaging suggested that cells were attached to Fe(0). The corrosion enhancement mechanism is for all tested strains likely related to free extracellular components catalyzing hydrogen formation on the Fe(0) surface, or to the maintenance of low hydrogen concentrations on the Fe(0) surface by attached cells thereby thermodynamically favoring hydrogen formation.
迄今所知，球形红杆菌相关菌株是唯一能促进金属铁腐蚀的同型产乙酸菌。本研究的目的是分离能够利用 Fe(0) 作为电子供体的其他同型产乙酸细菌，并探索其细胞外电子传递机制。从缺氧腐蚀产物中进行了富集，得到了产乙酸菌作为主要的同型产乙酸属。使用带有 Fe(0) 粉末顶层的新平板进行了分离。除了分离到一株球形红杆菌外，还分离到一株与 A. malicum 和 A. wieringae 密切相关的产乙酸菌。与非生物对照相比，产乙酸菌分离株显著增加了 Fe(0) 腐蚀（增加了 1.44 ± 0.16 倍）。A. woodii 的类型菌株的腐蚀增加幅度为 1.28 ± 0.13 倍，而球形红杆菌的类型菌株的腐蚀增加幅度为 2.03 ± 0.22 倍。氢介导了产乙酸菌和测试的类型菌株从 Fe(0) 中摄取电子。培养基的交换和 SEM 成像表明细胞附着在 Fe(0)上。对于所有测试的菌株，腐蚀增强机制可能与在 Fe(0)表面上催化氢形成的游离细胞外成分有关，或者与附着细胞在 Fe(0)表面上维持低氢浓度有关，从而从热力学上有利于氢的形成。
