Abstract: Leaves of Stevia rebaudiana contain steviol glycoside which mainly comprise of stevioside, a natural sweetener compound that is 100-300 times sweeter than sucrose. Current cultivation method of Stevia rebaudiana in Indonesia has yet to reach its optimum efficiency and productivity to produce stevioside as a safe sugar substitute sweetener for people with diabetes. An alternative method that is not limited by environmental factor is in vitro temporary immersion system (TIS) culture method using recipient for automated immersion (RITA®) bioreactor. The aim of this research was to evaluate the effect of red LED light induction towards shoot growth and stevioside accumulation in TIS RITA® bioreactor system, as an endeavour to increase the secondary metabolite synthesis. The result showed that the stevioside accumulation in TIS RITA® bioreactor system induced with red LED light for one hour during night was higher than that in TIS RITA® bioreactor system without red LED light induction, i.e. 71.04 ± 5.36 μg/g and 42.92 ± 5.40 μg/g respectively. Biomass growth rate reached as high as 0.072 ± 0.015/day for red LED light induced TIS RITA® bioreactor system, whereas TIS RITA® bioreactor system without induction was only 0.046 ± 0.003/day. Productivity of Stevia rebaudiana shoots induced with red LED light was 0.065 g/L medium/day, whilst shoots without any induction was 0.041 g/L medium/day. Sucrose, salt, and inorganic consumption in both bioreactor media increased as biomass increased. It can be concluded that Stevia rebaudiana shoot in TIS RITA® bioreactor induced with red LED light produces biomass and accumulates higher stevioside concentration, in comparison to bioreactor without any light induction.
Abstract: Stevia rebaudiana Bertoni (natural sweetener) belongs
to Asteraceae family and can be used as substitute of artificial
sweeteners for diabetic patients. Conventionally, it is cultivated by
seeds or stem cutting, but seed viability rate is poor. A protocol for
callus induction and multiplication was developed to produce large
no. of calli in short period. Surface sterilized nodal, leaf and root
explants were cultured on Murashige and Skoog (MS) medium with
different concentrations of plant hormone like, IBA, kinetin, NAA,
2,4-D, and NAA in combination with 2,4-D. 100% callusing was
observed from leaf explants cultured on combination of NAA and
2,4-D after three weeks while with 2,4-D, only 10% callusing was
observed. Calli obtained from leaf and root explants were shiny green
while with nodal explants it was hard and brown. The present
findings deal with induction of callusing in Stevia to achieve the
rapid callus multiplication for study of steviol glycosides in callus
culture.