Impact of conditioned medium on cell cultures of Panax notoginseng in an airlift bioreactor

The impact of conditioned medium addition on cell growth and production of ginseng polysaccharide by Panax notoginseng cells was investigated in 1 l concentric-tube airlift bioreactors. The maximum dry cell weight (DW) for a conventional cell culture in MS medium was 12.24 ± 0.60 g l^-1 at day 15 with an average growth rate of 0.156 ± 0.011 day^-1. In the cell cultures with addition of 50% (by volume) conditioned medium, a cell density (by dry weight) of 13.50 ± 2.81 g l^-1 at day 14 and an average growth rate of 0.192 ± 0.055 day^-1 were obtained. The maximum DW obtained in a high-density culture was 22.55 ± 4.78 g l^-1 on day 17 with an average growth rate of 0.231 ± 0.061 day^-1, and 24.12 ± 1.85 g l^-1 on the same day with an average growth rate of 0.251 ± 0.024 day^-1 in the high-density culture with conditioned medium. The production and productivity of ginseng polysaccharide in the conventional culture was 1.23 ± 0.16 g l^-1 (on day 16) and 49.2 ± 13.1 mg l^-1 day^-1, respectively, and a much higher production titre of 3.12 ± 0.37 g l^-1 (day 17) and a productivity of 151.8 ± 25.6 mg l^-1 day^-1 were achieved in high-density cell culture with addition of conditioned medium. Addition of conditioned medium effectively enhanced cell growth and accumulation of ginseng polysaccharide in both conventional and high-density cell cultures in the airlift bioreactors.