Improved indirubin production in a two-phase suspension culture of Polygonum tinctorium using dimethylpolysiloxane

Dimethylpolysiloxane (DMPS), used as a second phase in a suspension culture of Polygonum tinctorium, increased indirubin production by up to 259% and 16% in shake flask and air-lift bioreactors, respectively. In the shake flask culture, indirubin production increased by up to 248 mg/l using 90% v/v DMPS (volume of DMPS/volume of medium). In an air-lift bioreactor culture grown at a perfusion rate of 0.05 day(-1) the indirubin concentration reached a maximum of 130 mg/l using 50% (v/v) DMPS. For the same DMPS content, the lower indirubin production in an air-lift bioreactor was probably due to the mass transfer limitation of indirubin between the two phases.