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Commercial-scale Production of Valuable Plant Biomass and Secondary Metabolites
seed bioreactor with a motor-driven blade. The growth temperature of the DTBB was controlled
by circulating tempered water into the outside jacket.
Figure 3. Balloon-type Bubble Bioreactor (A) and Drum-type Bubble Bioreactor (B)
To develop a contamination-free system, a simple transfer system automatically controlled
(Figure 4) for root cultures and media was deliberately designed in which the culture material
was transferred from the small bioreactor to the main bioreactor by using sterilized air pressure.
The growth and saponin production patterns were almost the same regardless of the culture
scale. The mean maximum biomass produced from a 20 kL DTBB was more than 500 kg in
fresh weight after 56 days from inoculation. For the analysis of ginseng saponins, ginseng roots
were air-dried, extracted with 70% ethanol for 3 hr, concentrated to dryness by evaporation, and
redissolved in water for HPLC analysis. To improve the saponin yield in the cultures, various
types of elicitors were tested.
Figure 4. Operation of the Commercial-scale Bioreactor System (left)
Is Centrally Controlled (right)
APPLICATIONS OF ROOT CULTURE
Plant secondary metabolites are usually produced in differentiated tissues (roots and shoots)
at distinct developmental stages, but they are not synthesized at significant levels in undifferentiated
cultures (callus and suspension cultures). In most cases, root culture provides an efficient
method of secondary metabolite production, attributable to the rapid growth rate of roots in in
vitro culture and the stable production of secondary metabolites in roots (Hadacek, 2002; Rao
– 69 –