Characterization and application of large disposable shaking bioreactors
- Charakterisierung und Anwendung der großen geschüttelten Wegwerfbioreaktoren
Raval, Keyur; Büchs, Jochen (Thesis advisor)
Aachen : Publikationsserver der RWTH Aachen University (2008)
Dissertation / PhD Thesis
Aachen, Techn. Hochsch., Diss., 2008
Application of a shaking bioreactor system at pilot-scale level is presented in this research work. This very simple, versatile and widely used technology was combined with the cylindrical disposable reactors to make it an ideal choice for cultivation of plant, animal and insect cell cultures for pilot-scale production. Cylindrical reactors of size 2L, 20L and 50L were thoroughly characterized in terms of important engineering parameters such as mixing, power consumption, heat transfer rate and oxygen transfer rate. Complete mixing of fluid was achieved within few seconds at shaking frequencies as low as 80 rpm. Power consumption for fluids whose physical properties do not vary drastically over temperature was measured by the temperature method. The method was extended to incorporate changes in fluid physical properties such as viscosity, density etc. over temperature. Operating conditions where poor mixing might be observed were identified and a non-dimensional description of power consumption is given for the reactor system. High rates of heat generation were observed in 20L and 50L reactors especially for shaking frequencies higher than 230 rpm. Experiments revealed maximum of 16 K and 30 K increase in fluid temperature for water and a 80% glycerol/water mixture at 300 rpm, respectively. Although thorough ventilation may not be mandatory for slow growing animal and insect cell culture, a thorough ventilation of the surrounding atmosphere is mandatory, especially for high cell density cultivation of fast growing plant cell culture systems e.g. Nicotiana tabacum suspension culture to avoid any temperature stress. Oxygen transfer rate was measured by a well researched sulfite oxidation method. The maximum value of oxygen transfer rate measured in 20L and 50L reactors were 0.032 mol/L/h and 0.028 mol/L/h, respectively. Mass transfer coefficient was correlated with respect to energy dissipation. A therapeutic protein production process based on relatively less hydro-mechanical stress sensitive and one of the fastest growing N. tabacum plant cell suspension culture was successfully scaled-up from a 250 mL shake flask culture to 50L cylindrical disposable shaking bioreactor. The cell growth and protein production was comparable to that observed in other bioreactor systems. An animal cell culture process based on hybridoma-cmyc cells was also scaled-up successfully to a 2L cylindrical disposable shaking bioreactor.