Moon Ji-Won, Roh Yul, Lauf Robert J, Vali Hojatollah, Yeary Lucas W, Phelps Tommy J
Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
J Microbiol Methods. 2007 Jul;70(1):150-8. doi: 10.1016/j.mimet.2007.04.012. Epub 2007 Apr 29.
A microbial process that exploits the ability of iron-reducing microorganisms to produce copious amounts of extra-cellular metal (M)-substituted magnetite nanoparticles using akaganeite and dopants of dissolved form has previously been reported. The objectives of this study were to develop methods for producing M-substituted magnetite nanoparticles with a high rate of metal substitution by biological processes and to identify factors affecting the production of nano-crystals. The thermophilic and psychrotolerant iron-reducing bacteria had the ability to form M-substituted magnetite nano-crystals (M(y)Fe(3-y)O(4)) from a doped precursor, mixed-M iron oxyhydroxide, (M(x)Fe(1-x)OOH, x< or =0.5, M is Mn, Zn, Ni, Co and Cr). Within the range of 0.01< or =x< or =0.3, using the mixed precursor material enabled the microbial synthesis of more heavily substituted magnetite compared to the previous method, in which the precursor was pure akaganeite and the dopants were present as soluble metal salts. The mixed precursor method was especially advantageous in the case of toxic metals such as Cr and Ni. Also this new method increased the production rate and magnetic properties of the product, while improving crystallinity, size control and scalability.
先前已有报道称，一种微生物过程利用了铁还原微生物的能力，即使用赤铁矿和溶解形式的掺杂剂来生产大量细胞外金属（M）取代的磁铁矿纳米颗粒。本研究的目的是开发通过生物过程以高金属取代率生产M取代磁铁矿纳米颗粒的方法，并确定影响纳米晶体生产的因素。嗜热和耐冷铁还原细菌能够从掺杂的前体混合M铁羟基氧化物（M(x)Fe(1-x)OOH，x≤0.5，M为Mn、Zn、Ni、Co和Cr）形成M取代的磁铁矿纳米晶体（M(y)Fe(3-y)O(4)）。在0.01≤x≤0.3范围内，与之前的方法相比，使用混合前体材料能够使微生物合成取代度更高的磁铁矿，在之前的方法中，前体是纯赤铁矿，掺杂剂以可溶性金属盐的形式存在。混合前体法在Cr和Ni等有毒金属的情况下特别有利。此外，这种新方法提高了产物的产率和磁性，同时改善了结晶度、尺寸控制和可扩展性。
