Biological control of the size and reactivity of catalytic Pd(0) produced by Shewanella oneidensis
Biological control of the size and reactivity of catalytic Pd(0) produced by Shewanella oneidensis
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DOI：
10.1007/s10482-006-9088-4
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发表时间：
2006-11-01
影响因子：
2.6
通讯作者：
Verstraete, Willy
中科院分区：
文献类型：
--
作者：
De Windt, Wim;Boon, Nico;Verstraete, Willy
Pd(0) 还原沉淀过程中 Shewanella oneidensis MR-1 与可溶性金属 Pd(II) 之间的相互作用决定了沉淀 Pd(0) 纳米粒子的尺寸和性质。细胞活力评估表明，Pd(II) 的生物还原是一种解毒机制，具体取决于 Pd(II) 浓度以及电子供体的存在和特性。在顶部空间添加 H-2 使得 S. oneidensis 能够抵抗 Pd(II) 的毒性作用。有趣的是，25 mM 甲酸对于 Pd(II) 生物还原解毒来说是不太有效的电子供体，因为在 60 分钟内可培养细胞减少了 2 个对数，活细胞减少了 20%，随后恢复缓慢。当 Pd(II) 浓度为 50 mg (-l) 时，Pd: 细胞干重 (CDW) 之比低于 5:2 时，大多数细胞仍能存活。这些活细胞在相对较大的细菌表面积上沉淀 Pd(0) 晶体，与在非活生物质上形成的 Pd(0) 晶体相比（Pd:CDW 比率为 5:2），颗粒面积小 100 倍。非活生物质上相对较大且密集覆盖的Pd（0）晶体对疏水性分子（例如多氯联苯）表现出高催化反应性，而活细菌载体上较小且更分散的纳米晶体对阴离子污染物高氯酸盐的还原降解表现出高催化反应性。
The interaction between Shewanella oneidensis MR-1 and the soluble metal Pd(II) during the reductive precipitation of Pd(0) determined the size and properties of the precipitated Pd(0) nanoparticles. Assessment of cell viability indicated that the bioreduction of Pd(II) was a detoxification mechanism depending on the Pd(II) concentration and on the presence and properties of the electron donor. The addition of H-2 in the headspace allowed S. oneidensis to resist the toxic effects of Pd(II). Interestingly, 25 mM formate was a less effective electron donor for bioreductive detoxification of Pd(II), since there was a 2 log reduction of culturable cells and a 20% decrease of viable cells within 60 min, followed by a slow recovery. When the ratio of Pd:cell dry weight (CDW) was below 5:2 at a concentration of 50 mg (-l) Pd(II), most of the cells remained viable. These viable cells precipitated Pd(0) crystals over a relatively larger bacterial surface area and had a particle area that was up to 100 times smaller when compared to Pd(0) crystals formed on non-viable biomass (Pd:CDW ratio of 5:2). The relatively large and densely covering Pd(0) crystals on non-viable biomass exhibited high catalytic reactivity towards hydrophobic molecules such as polychlorinated biphenyls, while the smaller and more dispersed nanocrystals on a viable bacterial carrier exhibited high catalytic reactivity towards the reductive degradation of the anionic pollutant perchlorate.