Production of secondary metabolites from PLBs of Dendrobium candidum: The Standardization of Culture Condition for Efficient Induction of Secondary Metabolites

To establish an efficient culture protocol for production of biomass and bioactive compound, protocorm-like bodies (PLBs) of Dendrobium candidum were induced from stem segments using solid MS medium supplemented with 0.5 mg/L kinetin, 30g/L sucrose and 2.3 g/L Gelrite. By inoculating 80 g/L of PLBs in 1/2 MS medium containing 30 g/L sucrose at an initial medium pH of 5.0 under a 10 µmol m-2 s-1 PPF, the maximum growth as well as the maximum polysaccharide production was achieved. To elucidate optimum growth period, Dendrobium candidum PLBs were cultured for 49 days. Maximum PLBs growth was noted after 35 days of culture, however the polysaccharide content reached maximum after 21 days of culture. As an enhancement strategy medium replenishment and elicitation techniques were adopted. The highest accumulation of biomass and polysaccharide was achieved when culture fed with 1/2 MS medium containing 3% sucrose after 3 weeks. In addition, the highest accumulation of phenolics, flavonoids and total polysaccharides was obtained when cultures elicited with 100μM methyl jasmonate (MJ). Contrary, the higher concentration of MJ strongly inhibited the growth of PLBs.