Effects of oxygen, carbon dioxide and ethylene on growth and bioactive compound production in bioreactor culture of ginseng adventitious roots

The gaseous composition in plant cell and tissue cultures is an important factor affecting the plant physiology. Gaseous composition, especially O-2, CO2 and C2H4 has profound effect on cell growth and secondary metabolite production. in this work, we investigated the effects of O-2, CO2 and C2H4 on adventitious root growth, ginsenoside and polysaccharide production using bioreactor system. The results showed significant increase of dry weight with the gaseous compositions of 10 ppm (57.9 g) and 20 ppm (55.17 g) ethylene as compared to control as well as other treatments at the end of culture but CO2 and C2H4 were unfavorable to the adventitious root culture due to low ginsenoside production. Oxygen concentration of 40% was found optimal for the production of adventitious root mass, ginseng saponin and polysaccharide. The kinetics of changes in ion concentrations, sugar and electrical conductivity (EC) in the media was monitored to understand the relationship between growth, ginsenoside production and nutrient partitioning. Our results indicate that EC, sugar and mineral ions decreased with the progress of the experiment. With the progress of the experiment, sugars and mineral ions were utilized by the adventitious roots for the production of biomass resulting continuous decrease in EC. The interaction among gaseous metabolites, kinetics of changes in ion concentrations, sugar uptake and ginsenoside formation were also elucidated. This information will facilitate the rational operation of bioreactor culture system producing secondary metabolites. (c) 2005 Elsevier B.V. All rights reserved.