Production of podophyllotoxin by plant cell cultures of Podophyllum hexandrum in bioreactor.

Submerged cultivation of Podophyllum hexandrum for the production of podophyllotoxin was carried out in a 3l stirred tank bioreactor fitted with a low-shear Setric impeller. The specific requirements of the medium, such as carbon source (sugar) and light, were established for the growth of and podophyllotoxin production by P. hexandrum in suspension cultures. Substitution of sucrose by glucose resulted in higher growth and podophyllotoxin production. The biosynthesis of podophyllotoxin was favored when plant cells were cultivated in the dark. An agitation speed of 100 rpm was sufficient to mix the culture broth in the bioreactor without causing any significant cell damage. Biomass and podophyllotoxin accumulation in 3 l bioreactor under batch growth conditions were 6.5 g/l and 4.26 mg/l, respectively, in 22 d. This resulted in an overall podophyllotoxin productivity of 0.19 mg/(l.d), which represented an increase of 27% in comparison to its productivity in a shake flask. Podophyllotoxin production was found to be a combined growth-associated and non-growth associated process.