Volumetric mass transfer coefficient, power input and gas hold-up in viscous liquid in mechanically agitated fermenters. Measurements and scale-up

Bubble size and liquid-side mass transfer coefficient measurements in aerated stirred tank reactors with non-Newtonian liquids

“…A first set of engineering tools that can help perform the scale-up of such processes is composed of correlations able to predict the majority of impacting parameters such as: dissipated power, gas holdup, mass transfer coefficient, and mixing time (Garcia-Ochoa and Gomez (2009), Gabelle et al (2011), Petříček et al (2018)). This approach is necessary to design industrial-scale bioreactors, but it is hazardous, as the empirical correlations are usually validated only at scales much smaller (∼ 0.001-0.1 m…”

Oxygen transfer and bubble sizes occurring in a pilot‐scale cultivation of Bacillus velezensis 83 for the production of poly(γ‐glutamic acid) under two schemes of power drawn

“…Several recent works focusing on bioreactor hydrodynamics and oxygen transfer (in terms of bubble size or k L a as a function of different parameters) have been performed using model fluids. [24][25][26][27][28] Although considerable basic information may be obtained from these model systems, extrapolation to more complex real systems is not always justified. Moreover, few works are available in which the power input is accurately measured in actual fermentations; representative works include those published by Rocha-Valadez et al 19 and Amanullah et al 29 PGA production is an attractive model for analyzing mass transfer and air dispersion, involving a fast fermentation which generates broths of low turbidity and exhibits non-Newtonian rheological behavior which affects the oxygen transfer.…”

“…For mycelial fermentations, in which the presence of solids is hydrodynamically relevant, pulp paper suspensions are used to simulate the actual fermentation behaviors. Several recent works focusing on bioreactor hydrodynamics and oxygen transfer (in terms of bubble size or k L a as a function of different parameters) have been performed using model fluids 24‐28 . Although considerable basic information may be obtained from these model systems, extrapolation to more complex real systems is not always justified.…”

A General Review of the Current Development of Mechanically Agitated Vessels

“…The key parameter for bioprocesses is the volumetric mass transfer coefficient (k L a) during which the gas-liquid mass transfer rate is controlled. Petrícek et al [98][99][100][101] examined typical situation for aerobic fermentation (the biomass is shear-rate sensitive) in which viscous batches are usually used, in term of impeller shape and vessel size using Rushton turbines in single-double-and triple-impeller configurations. Based on the experimental data and by using the dynamic pressure method (DPM), the authors applied two different approaches.…”