o Fermentation and Biochemical Engineering Handbook AIR FLOW RATE (vm Figure 22. Effect of the airflow rate on ku a in rotating drum fermenter. (Tanaka, H, et al Spin Filter Bioreactor. This type of bioreactor(Styer, 1985)16 is equipped with a filter driven by a magnetic coupling in the stir plate( Fig. 26) tic coup This spinning filter operates as a medium agitator without generating shear stress and also serves as an excellent filter for the removal ofthe medium from filter bie will be most suitable for the continuous culture of plant cells. When a conventional bioreactor was used and the feeding rate ofthe medium was increased, the cell density was decreased because of washout. However, when a spin filter bioreactor was used, the cell density was maintained constant and half of the spent medium was effectively removed through the spin filter Gaseous Phase Bioreactor, As shown in Fig. 24, this type of bioreactor is equipped with filters on which the culture is supported and with a shower nozzle for spraying on the medium(Ushiyama et al., 1984; 7J Ushiyama, 1988). 18 Seed cultures are inoculated on the filters and the medium is supplied to the culture by spraying from a shower nozzle. The drained medium is collected on the bottom of the bioreactor. This type of bioreactor is excellent for plant cell, tissue, and organ cultures because there is no mechanical agitation(.g, driven impeller, aerator) and, therefore, the growth rate and the secondary metabolite production are enha Light Introducing Bioreactor. Plants are susceptible to light irradiation and as a consequence various metabolic and/or physiological changes are generated. Some important reactions are: (i) photosynthesis (ii) activation of specific enzymes such as phenylalanine ammonia lyase (PAL) and to induce the production of flavonoids or anthodyanins, (iii) photomorphogenesis such as development of leaves. For these reactions, theRo!ation speed 5:: 0 AIR FLOW RATE (wm) 5 Figure 22. Effect ofthe airflow rate on k,a in rotating drum fermenter. (Tanaka, H., et al., 1983) Spin Filter Bioreactor. This type of bioreactor (Styer, 1985)[161 is equipped with a filter driven by amagnetic coupling in the stir plate (Fig. 26). This spinning filter operates as a medium agitator without generating shear stress and also serves as an excellent filter for the removal ofthe medium from the bioreactor without the cells plugging it. The spin filter bioreactor will be most suitable for the continuous culture of plant cells. When a conventional bioreactor was used and the feeding rate ofthe medium was increased, the cell density was decreased because of washout. However, when a spin filter bioreactor was used, the cell density was maintained constant and half of the spent medium was effectively removed through the spin filter. Gaseous Phase Bioreactor. As shown in Fig. 24, this type of bioreactor is equipped with filters on which the culture is supported and with a shower nozzle for spraying on the medium (Ushiyama et al., 1984;[”] Ushiyama, 1988).[’*] Seed cultures are inoculated on the filters and the medium is supplied to the culture by spraying from a shower nozzle. The drained medium is collected on the bottom of the bioreactor. This type of bioreactor is excellent for plant cell, tissue, and organ cultures because there is no mechanical agitation (e.g., driven impeller, aerator) and, therefore, the growth rate and the secondary metabolite production are enhanced. Light Introducing Bioreactor. Plants are susceptible to light irradiation and as a consequence various metabolic and/or physiological changes are generated. Some important reactions are: (i) photosynthesis, (ii) activation of specific enzymes such as phenylalanine ammonia lyase (PAL) and to induce the production of flavonoids or anthodyanins, (iii) photomorphogenesis such as development of leaves. For these reactions, the