Royer Richard A, Dempsey Brian A, Jeon Byong-Hun, Burgos William D
Department of Civil and Environmental Engineering, The Pennsylvania State University, 212 Sackett Building, University Park, Pennsylvania 16802, USA.
Environ Sci Technol. 2004 Jan 1;38(1):187-93. doi: 10.1021/es026466u.
Bacterial dissimilatory iron reduction is self-inhibited by the production of ferrous [Fe(II)] iron resulting in diminished iron reduction as Fe(II) accumulates. Experiments were conducted to investigate the mechanisms of Fe(II) inhibition employing the dissimilatory metal-reducing bacterium Shewanella putrefaciens strain CN32 under nongrowth conditions in a system designed to minimize precipitation of ferrous iron minerals. After an initial period (ca. 1 day) of relatively rapid iron reduction, hematite reduction rates were controlled by mass transfer of Fe(II). Experiments in which hematite was equilibrated with Mn(II) prior to inoculation indicated that the observed inhibition was not due to Fe(II) sorption. At longer times, soluble Fe(II) accumulated such that the reaction was slowed due to a decreased thermodynamic driving force. The thermodynamic evaluation also supported the prior conclusion that hydrated hematite surface sites may yield substantially more energy during bioreduction than "bulk" hematite. For well-mixed conditions, the rates of hematite reduction were directly proportional to the biologically available reaction potential.
细菌异化铁还原作用会因亚铁[Fe(II)]的产生而受到自身抑制，随着Fe(II)的积累，铁还原作用会减弱。在一个旨在尽量减少亚铁矿物沉淀的系统中，利用异化金属还原菌腐败希瓦氏菌菌株CN32，在非生长条件下进行了实验，以研究Fe(II)抑制作用的机制。在最初相对快速的铁还原阶段（约1天）之后，赤铁矿的还原速率受Fe(II)的传质控制。接种前将赤铁矿与Mn(II)平衡的实验表明，观察到的抑制作用并非由于Fe(II)吸附。在较长时间内，可溶性Fe(II)积累，导致反应因热力学驱动力降低而减缓。热力学评估也支持了先前的结论，即水合赤铁矿表面位点在生物还原过程中可能比“块状”赤铁矿产生更多能量。在充分混合的条件下，赤铁矿的还原速率与生物可利用的反应电位成正比。
