C. asiatica (Umbelliferae) or locally known as "pegaga" cell suspension
culture is used as a model system to produce triterpenoids (TTPs). Cell growth and
TTPs production were optimized at shake flask level. Different factors such as
nutritional requirement and environmental conditions were screened and optimized
using Response Surface Methodology (RSM) experimental design. Preliminary
study of laboratory-scale bioreactor was done to study cell growth at regulated pH.
Kinetics and modeling studies were carried out aimed at evaluating growth and
production parameters for better understanding and control of the process. This
study was conducted as foundation for production of triterpenoids at commercial
scale.
Growth medium (G) was developed for optimum cell growth by
manipulation of different inoculum age and size, sucrose concentration, hormone
combination and concentration, incubatOptimization strategies by RSM has established cell growth of C. asiatica above 16
g L⁻¹ at 25°C, pH 5.65 and light intensity of 734 lux; medium NH₄⁺:NO₃⁻ ratio
between 0.45-0.9, higher pol-at 2.6 mM, sucrose concentration around 6.68% in
combination with 0.84 mg L⁻¹ IAA and 1.17 mg L⁻¹ BAP and higher total number of
nitrogen around 40 mM. Maximum cell dry weight around 27 g L⁻¹ was attained
with G medium. However, TTPs production was not significantly affected by all
factors because of very low production.
Cell growth rate at 0.09 day⁻¹ (td=7.5 days) was 1.5 times higher when
medium pH was controlled at pH 4 in stirred-tank: bioreactor. However, maximum
cell dry weight at 8.6 g L⁻¹ was 1.5 times higher when pH was not controlled, with in
almost three times more efficient sucrose utilization at 0.28 g cell g⁻¹ sucrose.
Higher growth rate at 0.18 day⁻¹ in bioreactor cultivation (B) was only 20% higher
than shake flask cultivation However, maximum cell dry weight at 10.5 g L⁻¹ in M
was 14% higher than in B.A 97% confidence was achieved by fitting three
unstructured growth models; Monod, Logistic and Gompertz equations to the cell
growth data. The deviation in Logistic
and Gompertz models could be due the model was developed for substrateindependent
growth and fungi growth, respectively
