Impact of operating parameters on values of a volumetric mass transfer coefficient in a single-use bioreactor with wave-induced agitation

Disposable rocking bioreactors: recent applications and progressive perspectives

Disposable rocking bioreactors facilitate scaling up animal and plant cell biomass propagation and developing specified bioprocesses like manufacturing vaccines or chimeric antigen receptor (CAR) T cells. Future contexts for these bioreactors include supporting regenerative medicine, recognising metabolic responses of biochemically or mechanically stressed cells, continuously performing in vitro bioprocesses, or cell-free protein synthesis systems.

Biotechnology and In Vitro Culture as an Alternative System for Secondary Metabolite Production

Medicinal plants are rich sources of bioactive compounds widely used as medicaments, food additives, perfumes, and agrochemicals. These secondary compounds are produced under stress conditions to carry out physiological tasks in plants. Secondary metabolites have a complex chemical structure with pharmacological properties. The widespread use of these metabolites in a lot of industrial sectors has raised the need to increase the production of secondary metabolites. Biotechnological methods of cell culture allow the conservation of plants, as well as the improvement of metabolite biosynthesis and the possibility to modify the synthesis pathways. The objective of this review is to outline the applications of different in vitro culture systems with previously reported relevant examples for the optimal production of plant-derived secondary metabolites.

Microcarrier-Supported Culture of Chondrocytes in Continuously Rocked Disposable Bioreactor

Disposable wave-assisted bioreactors are devices originally designed for scaling-up cultures of extremely fragile animal cells. In such bioreactors, agitation is achieved by continuous horizontal oscillations of disposable culture bag-like container fixed in a rocker unit. The continuous rocking movement of the container induces waves in the two-phase (i.e., gas-liquid) culture system composed of CO₂-enriched air and aqueous culture medium. Such continuously oscillating devices can be utilized for supporting homogeneity in systems for in vitro propagation of animal anchorage-dependent, that is, adherent, cells, like CP5 chondrocytes cells. As most of in vitro cultured cells exhibit anchorage-dependency toward solid surface, the suitable interface can be provided by beads of microcarriers made of polymers and characterized by large surface-to-volume ratio. This chapter describes a methodology for efficient propagation of CP5 chondrocytes on Cytodex 3 microcarriers performed in ReadyToProcess WAVE 25 disposable bioreactor, as well as all useful procedures for daily monitoring the growth of CP5 chondrocytes.

A General Review of the Current Development of Mechanically Agitated Vessels

The mixing process in a mechanically agitated vessel is a widespread phenomenon which plays an important role among industrial processes. In that process, one of the crucial parameters, the mixing efficiency, depends on a large number of geometrical factors, as well as process parameters and complex interactions between the phases which are still not well understood. In the last decade, large progress has been made in optimisation, construction and numerical and experimental analysis of mechanically agitated vessels. In this review, the current state in this field has been presented. It shows that advanced computational fluid dynamic techniques for multiphase flow analysis with reactions and modern experimental techniques can be used with success to analyse in detail mixing features in liquid-liquid, gas-liquid, solid-liquid and in more than two-phase flows. The objective is to show the most important research recently carried out.

Efficient propagation of suspended HL-60 cells in a disposable bioreactor supporting wave-induced agitation at various Reynolds number

Growth of human nonadherent HL-60 cell cultures performed in disposable bioreactor under various hydrodynamic conditions of 2-D wave-assisted agitation has been compared and discussed. Influence of Reynolds number for liquid (Re_L) and the k_La coefficient, as key parameters characterized the bioprocessing of HL-60 cells in ReadyToProcess WAVE^TM 25 system, on reached values of the apparent maximal specific growth rate (μ_max) and the specific yield of biomass (Y^*_X/S) has been identified. The values of Re_L (i.e., 510–10,208), as well as k_La coefficient (i.e., 2.83–13.55 h⁻¹), have been estimated for the cultures subjected to wave-induced mixing, based on simplified dimensionless correlation for various presents of WAVE 25 system. The highest values of apparent μ_max = 0.038 h⁻¹ and Y^*_X/S = 25.64 × 10⁸ cells g_glc⁻¹ have been noted for cultures independently performed at wave-induced agitation characterized by Re_L equaled to 5104 and 510, respectively. The presented results have high applicability potential in scale-up of bioprocesses focused on nonadherent animal cells, or in the case of any application of disposable bioreactors presenting similitude.

A mechanistic model for gas-liquid mass transfer prediction in a rocking disposable bioreactor

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 for k 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 a k 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 overall k 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.