Microbial Reduction of Fe(III) and Sorption/Precipitation of Fe(II) on Shewanella putrefaciens Strain CN32

详细信息    查看全文

• 作者：Chongxuan Liu ; John M. Zachara ; Yuri A. Gorby ; Jim E. Szecsody ; and Christopher F. Brown
• 刊名：Environmental Science & Technology
• 出版年：2001
• 出版时间：April 1, 2001
• 年：2001
• 卷：35
• 期：7
• 页码：1385 - 1393
• 全文大小：305K
• 年卷期：v.35,no.7(April 1, 2001)
• ISSN：1520-5851

文摘

The influence of Fe(II) on the dissimilatory bacterialreduction of an Fe(III) aqueous complex (Fe(III)-citrate_aq)was investigated using Shewanella putrefaciens strainCN32. The sorption of Fe(II) on CN32 followed a Langmuirisotherm. Least-squares fitting gave a maximum sorptioncapacity of Q_max = 4.19 × 10^-3 mol/10¹² cells (1.19 mmol/m² of cell surface area) and an affinity coefficient of logK = 3.29. The growth yield of CN32 with respect toFe(III)_aq reduction showed a linear trend with an averagevalue of 5.24 (±0.12) × 10⁹ cells/mmol of Fe(III). Thereduction of Fe(III)_aq by CN32 was described by Monodkinetics with respect to the electron acceptor concentration,Fe(III)_aq, with a half-saturation constant (K_s) of 29 (±3)mM and maximum growth rate (_max) of 0.32 (±0.02) h^-1.However, the pretreatment of CN32 with Fe(II)_aq significantlyinhibited the reduction of Fe(III)_aq, resulting in a lagphase of about 3-30 h depending on initial cell concentrations.Lower initial cell concentration led to longer lag phaseduration, and higher cell concentration led to a shorter one.Transmission electron microscopy and energy dispersivespectroscopy revealed that many cells carried surfaceprecipitates of Fe mineral phases (valence unspecified)during the lag phase. These precipitates disappeared afterthe cells recovered from the lag phase. The cell inhibitionand recovery mechanisms from Fe(II)-induced mineralprecipitation were not identified by this study, but severalalternatives were discussed. A modified Monod modelincorporating a lag phase, Fe(II) adsorption, and aqueouscomplexation reactions was able to describe theexperimental results of microbial Fe(III)_aq reduction andcell growth when cells were pretreated with Fe(II)_aq.