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A mechanistic model for gas–liquid mass transfer prediction in a rocking disposable bioreactor
Author(s) -
Bai Yun,
MooYoung Murray,
Anderson William A.
Publication year - 2019
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.27000
Subject(s) - bioreactor , mass transfer , aeration , entrainment (biomusicology) , mechanics , breaking wave , volume (thermodynamics) , mixing (physics) , scale up , chemistry , materials science , thermodynamics , physics , optics , acoustics , classical mechanics , wave propagation , organic chemistry , quantum mechanics , rhythm
Rocking disposable bioreactors are a newer approach to smaller‐scale cell growth that use a cyclic rocking motion to induce mixing and oxygen transfer from the headspace gas into the liquid. Compared with traditional stirred‐tank and pneumatic bioreactors, rocking bioreactors operate in a very different physical mode and in this study the oxygen transfer pathways are reassessed to develop a fundamental mass transfer ( k L a ) model that is compared with experimental data. The model combines two mechanisms, namely surface aeration and oxygenation via a breaking wave with air entrainment, borrowing concepts from ocean wave models. Experimental data fork L a across the range of possible operating conditions (rocking speed, angle, and liquid volume) confirms the validity of the modeling approach, with most predictions falling within ±20% of the experimental values. At low speeds (up to 20 rpm) the surface aeration mechanism is shown to be dominant with ak L a of around 3.5 hr −1 , while at high speeds (40 rpm) and angles the breaking wave mechanism contributes up to 91% of the overallk L a (65 hr −1 ). This model provides an improved fundamental basis for understanding gas–liquid mass transfer for the operation, scale‐up, and potential design improvements for rocking bioreactors.