Improved production of caffeic acid derivatives in suspension cultures of Echinacea purpurea by medium replenishment strategy.

The aim of this study was to produce caffeic acid derivatives from adventitious root cultures of Echinacea purpurea, which are of high pharmaceutical value. The effects of both media optimization and replenishment strategies were adopted to achieve improved production of E. purpurea adventitious roots and caffeic acid derivatives. Of the different media strengths (0.25 MS, 0.5 MS, 0.75 MS and 1 MS) tested for the culturing of adventitious roots in 5 L bioreactors, 0.5 MS medium was found to be most suitable for the growth of adventitious roots. The optima accumulation of biomass (73.6 g L(-1) FW and 10.03 g L(-1) DW), phenolics (61.14 mg g(-1) DW) and flavonoids (38.30 mg g(-1) DW) were achieved in this medium. Furthermore, fed batch cultivations (media replenishment with 0.25 MS, 0.5 MS, 0.75 MS and 1 MS at the end of 2nd and 3rd weeks) to further enhance the production of adventitious root biomass and metabolites were also attempted. High adventitious root biomasses (83.1 g L(-1) FW and 15.30 g L(-1) DW) were achieved with feeding of the 0.5 MS medium at the end of 2nd week. This led to slight decreases in the total production of phenolics and flavonoids; however, this feeding was responsible for increases in the accumulation of caftaric acid (5.76 mg g(-1) DW) and cichoric acid (26.12 mg g(-1) DW).