Business Potential for Agricultural Biotechnology - Asian Productivity ...

Business Potential for Agricultural Biotechnology Products
TISSUE CULTURE FOR GINSENG ROOT PROLIFERATION
Although hairy root (transformed root) cultures are a promising method known to be superior
for ginseng cell culture, this has also been known to produce opine-like chemicals which are
lethal to humans. To avoid this problem, the adventitious roots (Figure 2) induced from ginseng
callus were chosen for cultivation instead of the hairy roots (Son et al., 1999; Seon et al., 1999;
Choi et al., 2000; Paek et al., 2001).
Figure 2. Adventitious Roots Induced from Explants of Korean Mountain Ginseng Root
INDUCTION OF MULTIPLE ADVENTITIOUS ROOTS
Donor ginseng plants were washed and surface-sterilized before being subjected to aseptic
dissection into small pieces of explants. The explants were then cultured on MS solid media supplied
with various combinations of plant growth regulators (PGRs). After four weeks of cultivation,
rapidly growing cells produced on the surface of explants were isolated and subcultured
onto the same media for further growth of callus. The subcultures were repeated six times before
the effect of PGRs on the induction of adventitious roots from these calli was tested. It was
found that the levels and types of auxin in the growth medium played an essential role in determining
the number of induced roots (Son et al., 1999). IBA in particular induced significantly
more roots per segment than the other auxins. The roots induced by the IAA and 2,4-D treatments
displayed a slower growth rate and a vitrified morphology. However, the roots induced by
IBA and NAA showed a normal morphology.
BIOREACTOR CULTURE
For small-scale culture (5L and 20L) in the laboratory, a balloon-type bubble bioreactor
(BTBB) system made of glass, as shown in Figure 3A, was established. The root suspension
cultures grown in 1L Erlenmeyer flasks were harvested and cut using a motor-driven blade at 60
rpm to prepare a seed culture of 2-mm-sized root segments. The inoculum for each BTBB was
adjusted to 1% (w/v) of fresh weight. Culture growth in 5L and 20L bioreactors followed a
sigmoidal curve and produced the maximum biomass of 500g and 2.2 kg in fresh weight after 42
days of cultivation. Root cutting during the culture increased the root mass yield but did not
affect the saponin content per gram dry weight. Among the different growth media, SH media
gave the highest mean number of multiple roots.
For commercial-scale cultures, an airlift drum-type bubble bioreactor (DTBB) of 20 kL
volume capacity (Figure 3B) was employed. The DTBB was constructed of stainless steel with a
sliding-type front door. Importantly, an air sparger was positioned at the bottom of the DTBB for
the generation of air bubbles smaller than 0.5 µm in diameter. Sterilization of the DTBB was
performed by using filtrated pressure steam. The same media composition for DTBB as the
BTBB was used. The seed culture for DTBB was prepared by cutting the cultivated roots in the
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