Application of Euler-Lagrange CFD for quantitative evaluating the effect of shear force on C. tinctorius L. cell in a stirred tank bioreactor

Abstract

The relationship between shear environment and physiological characteristics of plant cells is always a crucial and challenging aspect in the scale up of suspension cultivations. In this work, we propose a quantitative method for evaluating the lethal effects of hydrodynamic on Carthamus tinctorius L. cell with computational fluid dynamic (CFD) technology and online capacitance viable cell detection. The study towards the effect of short term shear force on C. tinctorius L. cells was carried out in 5 L bioreactor under various overall shear intensities (0.02–1.82 w/kg), in which an online capacitance electrode was applied to count the dynamic vital cell. A first order kinetic model was achieved to describe the death rate in a time span of 60 min based on the capacitance. A product of the maximum shear stress and shear frequency (SSF) parameter, which is an evolution of energy dissipation/circulation function, was established to relate cell death rate to the shear environment. A good correlation between cell death kinetics and the SSF parameter was observed in the verification test in a 15 L STR bioreactor. SSF can be used to determine the maximum operating range of hydrodynamic stress, and improve the design and optimization of the of C. tinctorius L. cultivation in scale-up process.