The deactivation of protein biocatalysts even at relatively low temperatures is one of the principal drawbacks to their use. To aid in the development of novel biocatalysts, we have derived an equation for both time- and temperature-dependent activity of the biocatalyst based on known concepts such as transition state theory and the Lumry-Eyring model. We then derived an analytical solution for the total turnover number (ttn), under isothermal operation, as a function of the catalytic constant kcat, the unfolding equilibrium constant K, and the intrinsic first-order deactivation rate constant(s) k(d,i). Employing an immobilized glucose isomerase biocatalyst in a CSTR and utilizing a linear temperature ramp beyond the Tm of the enzyme, we demonstrate an accelerated method for extracting the thermodynamic and kinetic constants describing the biocatalyst system. In addition, we demonstrate that the predicted biocatalyst behavior at different temperatures and reaction times is consistent with the experimental observations.
In this contribution, a novel approach to determine acoustic eigenmodes in duct systems is presented. The approach combines Computational fluid dynamics, classical Network models of duct acoustics and the Nyquist criterion known from control theory, and is therefore called CNN-method. The method has been applied to a geometrically simple, but aero-acoustically non-trivial configuration -i.e. a sudden change in cross-sectional area connecting two ducts with non-zero mean flow -and validated against experimental data.
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