Effects of inoculum density and aeration rate on biomass and cichoric acid production in Echinacea purpurea L. hairy roots in bubble column bioreactor

In this research, Echinacea purpurea L. hairy roots were cultured in 1000 ml bubble column bioreactor containing 500 ml WPM liquid medium and the effects of inoculum densities (3, 6 and 9g l-1) and aeration rates (0.1, 0.2 and 0.4vvm) on biomass and cichoric acid production were investigated. Fresh and dry weights and also the cichoric acid content in hairy roots were measured after 30 days. The results showed that the highest amount of biomass (16.4g l-1 fresh weight and 2.084g l-1 dry weight) and cichoric acid (16.74mg g-1 DW) were produced in the inoculum density of 6 gl-1. The investigation of aeration rates on biomass and cichoric acid production showed that the maximum fresh weight (15.4g l-1) and dry weight (2.467g l-1) were obtained in aeration rate of 0.4vvm and the maximum cichoric acid content (12.74mg g-1 DW) was obtained in aeration rate of 0.2vvm. Overall, the inoculum density and aeration rate had considerable effects on the hairy root growth and development in bubble column bioreactor and they should be optimized for obtaining the highest hairy root biomass and secondary metabolites.