Kinsenoside and polysaccharide production by rhizome culture of Anoectochilus roxburghii in continuous immersion bioreactor systems

Abstract

Anoectochilus roxburghii (Wall) Lindl. (Orchidaceae) is a precious raw material for medicine. However, the wild resource of A. roxburghii has been endangered, and artificial cultivation results in low yields. To provide rhizomes of A. roxburghii as alternative plant materials, the present study used continuous immersion bioreactor systems to investigate several factors affecting rhizome biomass and bioactive compound accumulation. The bioreactor with a net at the bottom of the sphere in the bioreactor was suitable for production of rhizomes. The rhizome biomass and kinsenoside and polysaccharide accumulation peaked at 30 days of the bioreactor culture. Thus, 30 days was the appropriate culture period. Maximum rhizome biomass and kinsenoside and polysaccharide accumulation were determined when a bioreactor was inoculated with 12.5 g L− 1 (fresh weight) of rhizomes, aerated at 500 mL min− 1, and maintained under 45 µmol m− 2 s− 1 light intensity. This process resulted in the production of 2980.5 mg L− 1 of kinsenoside and 5672.9 mg L−1 of polysaccharides.