A robust methodology for kinetic model parameter estimation for biocatalytic reactions

Abstract

Effective estimation of parameters in biocatalytic reaction kinetic expressions are very important when building process models to enable evaluation of process technology options and alternative biocatalysts. The kinetic models used to describe enzyme-catalyzed reactions generally include several parameters, which are strongly correlated with each other. State-of-the-art methodologies such as nonlinear regression (using progress curves) or graphical analysis (using initial rate data, for example, the Lineweaver-Burke plot, Hanes plot or Dixon plot) often incorporate errors in the estimates and rarely lead to globally optimized parameter values. In this article, a robust methodology to estimate parameters for biocatalytic reaction kinetic expressions is proposed. The methodology determines the parameters in a systematic manner by exploiting the best features of several of the current approaches. The parameter estimation problem is decomposed into five hierarchical steps, where the solution of each of the steps becomes the input for the subsequent step to achieve the final model with the corresponding regressed parameters. The model is further used for validating its performance and determining the correlation of the parameters. The final model with the fitted parameters is able to describe both initial rate and dynamic experiments. Application of the methodology is illustrated with a case study using the ω-transaminase catalyzed synthesis of 1-phenylethylamine from acetophenone and 2-propylamine.

The specificity and kinetic mechanism of branched‐chain amino acid aminotransferase from Escherichia coli studied with a new improved coupled assay procedure and the enzyme's potential for biocatalysis

“…There is a need to obtain similarly accurate kinetic parameters of BCAT in the opposite direction of reaction and for a wider range of branched-chain 2-oxoacids, including those corresponding to non-natural amino acids of industrial interest. Such information would be of importance for evaluating process technology options [10]. Earlier studies [11][12][13][14][15] had alerted us to the potential of BCAT as a biocatalyst for production of high-value non-natural amino acids, such as L-tert-leucine and L-3-hydroxyadamantylglycine.…”

Emerging Enzyme-Based Technologies for Wastewater Treatment

“…Kinetic constants were evaluated for the free CPO and compared to the kinetics of the CPO-based conjugates, i.e., CPO-TiO 2 -NBs and CPO-PEG-TiO 2 -NBs, by using non-linear regression plots (107). Namely, the K m (substrate concentration at which the initial reaction rate is half maximal) and V max (maximum initial rate of an enzyme catalyzed reaction) values of the CPO-TiO 2 -NBs and CPO-PEG-TiO 2 -NBs conjugates are shown in Table 1 and reflect comparison to the free CPO in solution.…”

A Numerical Procedure for Model Identifiability Analysis Applied to Enzyme Kinetics

“…The enzyme requires the cofactor pyridoxal phosphate (PLP) to act as a shuttle to transfer the amine moiety between the molecules. Based on the robust methodology of Al-Haque et al (2012), the model is split to submodels and the identifiability procedure is performed for the initial forward reaction rate. Based on the robust methodology of Al-Haque et al (2012), the model is split to submodels and the identifiability procedure is performed for the initial forward reaction rate.…”