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Modeling chromate reduction in Shewanella oneidensis MR‐1: Development of a novel dual‐enzyme kinetic model
Author(s) -
Viamajala Sridhar,
Peyton Brent M.,
Petersen James N.
Publication year - 2003
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.10724
Subject(s) - shewanella oneidensis , kinetics , chromate conversion coating , chemistry , reduction (mathematics) , shewanella , enzyme , metal , kinetic energy , thermodynamics , nuclear chemistry , chromium , biochemistry , biology , bacteria , mathematics , physics , organic chemistry , genetics , geometry , quantum mechanics
Chromate (Cr(VI)) reduction tests were performed with nitrate‐ and fumarate‐grown stationary phase cultures of Shewanella oneidensis MR‐1 (henceforth referred to as MR‐1) and disappearance of Cr(VI) was monitored over time. A rapid initial decrease in Cr(VI) concentration was observed, which was followed by a slower, steady decrease. These observations appear to be consistent with our previous results indicating that Cr(VI) reduction in MR‐1 involves at least two mechanisms (Viamajala et al., 2002b). Modeling of metal reduction kinetics is often based on single‐enzyme Michaelis‐Menten equations. However, these models are often developed using initial rates and do not always match actual reduction profiles. Based on the hypothesis that multiple Cr(VI) reduction mechanisms exist in MR‐1, a model was developed to describe the kinetics of Cr(VI) reduction by two parallel mechanisms: (1) a rapid Cr(VI) reduction mechanism that was deactivated (or depleted) quickly, and (2) a slower mechanism that had a constant activity and was sustainable for a longer duration. Kinetic parameters were estimated by fitting experimental data, and model fits were found to correspond very closely to quantitative observations of Cr(VI) reduction by MR‐1. © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 83: 790–797, 2003.