Identification of Mn(II)-Oxidizing Bacteria from a Low-pH Contaminated Former Uranium Mine
Identification of Mn(II)-Oxidizing Bacteria from a Low-pH Contaminated Former Uranium Mine
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DOI：
10.1128/aem.01296-14
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发表时间：
2014-08-01
影响因子：
4.4
通讯作者：
Kuesel, Kirsten
中科院分区：
文献类型：
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作者：
Akob, Denise M.;Bohu, Tsing;Kuesel, Kirsten
生物锰氧化负责在环境中产生高反应性和丰富的锰氧化物相，从而减轻金属污染。然而，人们对低 pH 环境中锰的氧化知之甚少，在低 pH 环境中，采矿活动经常导致金属污染成为一个问题。我们从前铀矿开采场分离出 pH 5.5 的两种 Mn(II) 氧化细菌 (MOB)（Duganella 分离株 AB_14 和 Albidiferax 分离株 TB-2）和 9 个 pH 7 的菌株。分离株 TB-2 可能有助于酸性富锰底土中的锰氧化，因为一个密切相关的克隆占总群落的 16%。所有分离株均在较小的 pH 范围内氧化 Mn，而低 pH 样品中的分离株仅在 pH 值低于 6 时氧化 Mn。具有不同 pH 最适值的两个菌株对 Mn 氧化的 Fe 需求量不同，这表明在中性 pH 下发现的菌株对 Mn 的氧化与 Fe 氧化有关。分离耐受镍、铜和镉，并产生与钠锰矿和水钠锰矿相似的锰氧化物，后者存在于与锰氧化物相关的金属富集的地下层中。这表明 MOB 可以在中等酸性和中性 pH 环境中参与生物锰氧化物的形成。
Biological Mn oxidation is responsible for producing highly reactive and abundant Mn oxide phases in the environment that can mitigate metal contamination. However, little is known about Mn oxidation in low-pH environments, where metal contamination often is a problem as the result of mining activities. We isolated two Mn(II)-oxidizing bacteria (MOB) at pH 5.5 (Duganella isolate AB_14 and Albidiferax isolate TB-2) and nine strains at pH 7 from a former uranium mining site. Isolate TB-2 may contribute to Mn oxidation in the acidic Mn-rich subsoil, as a closely related clone represented 16% of the total community. All isolates oxidized Mn over a small pH range, and isolates from low-pH samples only oxidized Mn below pH 6. Two strains with different pH optima differed in their Fe requirements for Mn oxidation, suggesting that Mn oxidation by the strain found at neutral pH was linked to Fe oxidation. Isolates tolerated Ni, Cu, and Cd and produced Mn oxides with similarities to todorokite and birnessite, with the latter being present in subsurface layers where metal enrichment was associated with Mn oxides. This demonstrates that MOB can be involved in the formation of biogenic Mn oxides in both moderately acidic and neutral pH environments.