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Title: Kinetic Analysis of Microbial Reduction of Fe(III) in Nontronite

Abstract

Microbial reduction of structural Fe(III) in nontronite was studied in batch cultures under non-growth condition using Shewanella putrefaciens, strain CN32. The rate and extent of structural Fe(III) reduction was examined as a function of electron acceptor [Fe(III)] and bacterial concentration. Fe(II) sorptions onto nontronite and CN32 cells were independently measured and well-described by the Langmuir expression with affinity constant 2.3 and 2.25 for nontronite and cells, respectively. The Fe(II) sorption capacity of nontronite, however, decreased with increasing nontronite concentration, suggesting particulate agglomeration effect. An empirical equation for sorption capacity was derived from the sorption isotherms at different nontronite concentrations and was used to calculate the 'effective' Fe(III) concentration for bioreduction. The initial rate of microbial reduction was found to be first order with respect to the 'effective' Fe(III) concentration. A kinetic biogeochemical model was assembled that incorporated the first order rate expression with respect to the ‘effective’ Fe(III) concentration, rates and extent of Fe(II) sorption to cell and nontronite surfaces, and the empirical equation for sorption capacity. The model successfully described the experimental results of microbial reduction of nontronite with variable nontronite concentrations. The microbial reduction rate, after normalized to cell concentration, however, decreased with increasing cell concentration, indicating thatmore » cell concentration did not linearly affect the reduction as commonly assumed in literature. A nonlinear, saturation-type rate expression with respect to cell concentration was needed to model bioreduction at variable cell concentration. Our results indicated that the kinetics of microbial reduction of structual Fe(III) in nontronite can be modeled after consideration of Fe(II) production and sorption, its role in inhibiting further Fe(III) reduction, and nonlinear effect of cell concentration.« less

Authors:
; ;
Publication Date:
Research Org.:
Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
Sponsoring Org.:
USDOE
OSTI Identifier:
985054
Report Number(s):
PNNL-SA-49306
Journal ID: ISSN 0013-936X; ISSN 1520-5851; 4691; KP1302000; TRN: US201016%%1743
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Resource Relation:
Journal Name: Environmental Science & Technology, 41(7):2437-2444; Journal Volume: 41; Journal Issue: 7
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; AFFINITY; AGGLOMERATION; BATCH CULTURE; BINDING ENERGY; CAPACITY; ELECTRONS; ISOTHERMS; KINETICS; PARTICULATES; PRODUCTION; SORPTION; STRAINS; VALENCE; kinetics, microbial reduction, structual Fe(III), clay; Environmental Molecular Sciences Laboratory

Citation Formats

Jaisi, Deb P., Dong, Hailiang, and Liu, Chongxuan. Kinetic Analysis of Microbial Reduction of Fe(III) in Nontronite. United States: N. p., 2007. Web. doi:10.1021/es0619399.
Jaisi, Deb P., Dong, Hailiang, & Liu, Chongxuan. Kinetic Analysis of Microbial Reduction of Fe(III) in Nontronite. United States. doi:10.1021/es0619399.
Jaisi, Deb P., Dong, Hailiang, and Liu, Chongxuan. Thu . "Kinetic Analysis of Microbial Reduction of Fe(III) in Nontronite". United States. doi:10.1021/es0619399.
@article{osti_985054,
title = {Kinetic Analysis of Microbial Reduction of Fe(III) in Nontronite},
author = {Jaisi, Deb P. and Dong, Hailiang and Liu, Chongxuan},
abstractNote = {Microbial reduction of structural Fe(III) in nontronite was studied in batch cultures under non-growth condition using Shewanella putrefaciens, strain CN32. The rate and extent of structural Fe(III) reduction was examined as a function of electron acceptor [Fe(III)] and bacterial concentration. Fe(II) sorptions onto nontronite and CN32 cells were independently measured and well-described by the Langmuir expression with affinity constant 2.3 and 2.25 for nontronite and cells, respectively. The Fe(II) sorption capacity of nontronite, however, decreased with increasing nontronite concentration, suggesting particulate agglomeration effect. An empirical equation for sorption capacity was derived from the sorption isotherms at different nontronite concentrations and was used to calculate the 'effective' Fe(III) concentration for bioreduction. The initial rate of microbial reduction was found to be first order with respect to the 'effective' Fe(III) concentration. A kinetic biogeochemical model was assembled that incorporated the first order rate expression with respect to the ‘effective’ Fe(III) concentration, rates and extent of Fe(II) sorption to cell and nontronite surfaces, and the empirical equation for sorption capacity. The model successfully described the experimental results of microbial reduction of nontronite with variable nontronite concentrations. The microbial reduction rate, after normalized to cell concentration, however, decreased with increasing cell concentration, indicating that cell concentration did not linearly affect the reduction as commonly assumed in literature. A nonlinear, saturation-type rate expression with respect to cell concentration was needed to model bioreduction at variable cell concentration. Our results indicated that the kinetics of microbial reduction of structual Fe(III) in nontronite can be modeled after consideration of Fe(II) production and sorption, its role in inhibiting further Fe(III) reduction, and nonlinear effect of cell concentration.},
doi = {10.1021/es0619399},
journal = {Environmental Science & Technology, 41(7):2437-2444},
number = 7,
volume = 41,
place = {United States},
year = {Thu Apr 26 00:00:00 EDT 2007},
month = {Thu Apr 26 00:00:00 EDT 2007}
}