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Model-based identifiable parameter determination applied to a simultaneous saccharification and fermentation process model for bio-ethanol production

Authors

  • Diana C. López C.,

    Corresponding author
    1. Chair of Process Dynamics and Operation, Technische Universität Berlin, D-10623, Germany
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  • Tilman Barz,

    1. Chair of Process Dynamics and Operation, Technische Universität Berlin, D-10623, Germany
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  • Mariana Peñuela,

    1. Bioprocesses Research Group, Faculty of Engineering, Dept. of Chemical Engineering, University of Antioquia, Medellín, Colombia
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  • Adriana Villegas,

    1. Dept. of Chemical Engineering, Research Group in Simulation, Design, Control and Optimization of Chemical Processes (SIDCOP), University of Antioquia, Medellín, Colombia and Faculty of Engineering, Termomec Research Group, Cooperative University of Colombia, Medellín, Colombia
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  • Silvia Ochoa,

    1. Dept. of Chemical Engineering, Research Group in Simulation, Design, Control and Optimization of Chemical Processes (SIDCOP), University of Antioquia, Medellín, Colombia
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  • Günter Wozny

    1. Chair of Process Dynamics and Operation, Technische Universität Berlin, D-10623, Germany
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  • This article was published online on 8 June 2013. An error was subsequently identified. This notice is included in the online and print versions to indicate that both have been corrected 26 July 2013.

Abstract

In this work, a methodology for the model-based identifiable parameter determination (MBIPD) is presented. This systematic approach is proposed to be used for structure and parameter identification of nonlinear models of biological reaction networks. Usually, this kind of problems are over-parameterized with large correlations between parameters. Hence, the related inverse problems for parameter determination and analysis are mathematically ill-posed and numerically difficult to solve. The proposed MBIPD methodology comprises several tasks: (i) model selection, (ii) tracking of an adequate initial guess, and (iii) an iterative parameter estimation step which includes an identifiable parameter subset selection (SsS) algorithm and accuracy analysis of the estimated parameters. The SsS algorithm is based on the analysis of the sensitivity matrix by rank revealing factorization methods. Using this, a reduction of the parameter search space to a reasonable subset, which can be reliably and efficiently estimated from available measurements, is achieved. The simultaneous saccharification and fermentation (SSF) process for bio-ethanol production from cellulosic material is used as case study for testing the methodology. The successful application of MBIPD to the SSF process demonstrates a relatively large reduction in the identified parameter space. It is shown by a cross-validation that using the identified parameters (even though the reduction of the search space), the model is still able to predict the experimental data properly. Moreover, it is shown that the model is easily and efficiently adapted to new process conditions by solving reduced and well conditioned problems. © 2013 American Institute of Chemical Engineers Biotechnol. Prog., 29:1064–1082, 2013

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