Abstract

Environmental purification using microorganisms has drawn attention for the decontamination of ¹³⁷Cs released during a nuclear accident; however, Cs absorption by microorganisms is inhibited by the coexistence of potassium. In this study, we aimed to identify Cs-absorbing bacteria resistant to the inhibition of Cs absorption in the coexistence of potassium for the purpose of decontaminating ¹³⁷Cs-contaminated biomass. When anaerobic sludge was cultured with the addition of CsCl, Cs accumulated in the microorganisms. This may be because Cs administration promoted the growth of specific Cs-absorbing bacteria. Metagenomics analysis of flora showed that the Tepidibacter genus dominated in the presence of Cs. In addition, Tepidibacter mesophilus accumulated 61.8 kBq/g dry weight of ¹³⁷Cs in the presence of 4 mM K⁺, and presented high ¹³⁷Cs-absorption ability, even in the presence of K⁺. Moreover, 74% of ¹³⁷Cs absorption by anaerobic sludge was estimated to be due to bacteria of the Tepidibacter genus. It is assumed that ¹³⁷Cs in the surface soil layer can be absorbed by surrounding microorganisms along with microbial decomposition of biomass containing a large amount of K⁺. Therefore, anaerobic sludge containing Tepidibacter genus may be used in the decontamination process of Cs released into environment as a useful Cs-accumulating flora.

中文翻译：

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从厌氧消化污泥中鉴定能够在K +下累积137 Cs的新型细菌，以净化137 Cs污染的生物质

摘要

使用微生物进行环境净化已引起对核事故中释放的¹³⁷ Cs的净化的关注。然而，钾的共存抑制了微生物对Cs的吸收。在这项研究中，我们旨在鉴定对钾共存的Cs吸收具有抑制作用的Cs吸收细菌，以净化¹³⁷ Cs污染的生物质。在添加CsCl的情况下培养厌氧污泥时，Cs会在微生物中累积。这可能是因为Cs给药促进了特定的Cs吸收细菌的生长。菌群的元基因组学分析表明，在Cs的存在下，双歧杆菌属占优势。此外，嗜热嗜热双歧杆菌在4 mM K ⁺存在下累积的¹³⁷ Cs的干重为61.8 kBq / g ，即使在存在K ⁺的情况下也表现出较高的¹³⁷ Cs吸收能力。此外，估计厌氧污泥吸收的¹³⁷ Cs中有74％是由于Tepidibacter属的细菌引起的。据推测，表层土壤层中的¹³⁷ Cs可以被周围的微生物吸收，同时微生物分解含有大量K ⁺的生物质。因此，含有Tepidibacter属的厌氧污泥可用于释放到环境中的Cs作为有用的Cs累积菌群的去污过程。