Reduction of chalcogen oxyanions and generation of nanoprecipitates by the photosynthetic bacterium Rhodobacter capsulatus
Reduction of chalcogen oxyanions and generation of nanoprecipitates by the photosynthetic bacterium Rhodobacter capsulatus
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DOI：
10.1016/j.jhazmat.2013.12.028
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发表时间：
2014-03-30
影响因子：
13.6
通讯作者：
Zannoni, Davide
中科院分区：
文献类型：
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作者：
Borghese, Roberto;Baccolini, Chiara;Zannoni, Davide
兼性光合细菌Rhodobacter capsulatus的特征在于其与毒性含氧阴离子亚碲酸盐（Tel（IV））和亚硒酸盐（Se-IV）通过高度可变的抗性水平相互作用，所述抗性水平取决于生长模式，使得该细菌成为用于研究与硫属元素的微生物相互作用的理想生物体。正如我们过去所报道的，当氧阴离子亚碲酸盐被R.荚膜细胞通过乙酸通透酶，并在细胞质中以碎片样黑色细胞内沉积物的形式被还原至Te度，没有描述Se度沉淀的明确机制。在这里，我们提出了第一份报告的生物转化碲和硒氧阴离子到细胞外Te度和Se度纳米沉淀物（NPs）的厌氧光合生长培养的R。capsulatus作为外源添加的氧化还原介体指甲花醌，即2-羟基-1，4-萘醌的函数。NP的形成取决于用于细菌生长的碳源，并且硫族元素还原的速率在不同的指甲花醌浓度下是恒定的，与氧化还原介体的催化作用一致。X射线衍射（XRD）分析证明了纳米颗粒的Te度和Se度性质。(C)2013爱思唯尔有限公司版权所有。
The facultative photosynthetic bacterium Rhodobacter capsulatus is characterized in its interaction with the toxic oxyanions tellurite (Tel(IV)) and selenite (Se-IV) by a highly variable level of resistance that is dependent on the growth mode making this bacterium an ideal organism for the study of the microbial interaction with chalcogens. As we have reported in the past, while the oxyanion tellurite is taken up by R. capsulatus cells via acetate permease and it is reduced to Te degrees in the cytoplasm in the form of splinter-like black intracellular deposits no clear mechanism was described for Se degrees precipitation. Here, we present the first report on the biotransformation of tellurium and selenium oxyanions into extracellular Te degrees and Se degrees nanoprecipitates (NPs) by anaerobic photosynthetically growing cultures of R. capsulatus as a function of exogenously added redox-mediator lawsone, i.e. 2-hydroxy-1,4-naphthoquinone. The NPs formation was dependent on the carbon source used for the bacterial growth and the rate of chalcogen reduction was constant at different lawsone concentrations, in line with a catalytic role for the redox mediator. X-ray diffraction (XRD) analysis demonstrated the Te degrees and Se degrees nature of the nanoparticles. (C) 2013 Elsevier B.V. All rights reserved.