Research On Suspension Co-culture System Of Medicinal Echinacea Adventitious Roots

Echinacea species are popular herbal medicine used all over the world and food supplements for enhancing the immune system. However, conventional propagation of Echinacea is greatly impeded by low germination rates, and the plants need low temperature verbalization. Further, field production period is long, the yield is low, and the secondary metabolite content is affected by environmental conditions. Therefore, field-grown plants are difficult to satisfy international demand. For commercial scale production of bioactive compounds from Echinacea, we will use air-lift bioreactor to co-culture adventitious roots(AR) of three Echinacea species(Echinacea purpurea, Echinacea angustifolia, Echinacea pallida) and produce a higher quantity of bioactive compounds(including water-soluble polysaccharides, caffeic acid derivatives, total polyphenols and flavonoids). During bioreactor co-cultures, we will also produce unique caffeic acid derivatives of each species, e.g., chichoric acid, echinacoside and others simultaneously, and stimulate the accumulation of some caffeic acid derivatives by AR co-cultures are compared with single culture. To improve AR growth and secondary metabolite production, and to understand antioxidant activities, we investigated the influence of MS salt strength, sucrose concentration, initial cultivation time in co-cultures. This study would have the advantage of fast growth, high efficiency and large-scale multiplication, which provided a novel approach for large scale production of secondary metabolites and would be beneficial to conservation of that species. The main results are as follows:1. It was possible to establish the co-culture system of Echinacea AR. Among the co-culture combinations of Echinacea AR, Pu and Pa AR co-cultures were optimal for inducing the accumulation of biomass and secondary metabolites and the best inoculum size was determined to be 7 g/L FW(Pa:Pu=1:1).2. In 5L capacity airlift bioreactors, the Pa and Pu AR co-cultures increased dry weight(6.78 g/L) by 11.30% and 11.00%, respectively, compared with the single culture of Pu or Pa AR. The concentration of total polyphenols and flavonoids was found to be 38.40% and 74.10% higher in the Pa and Pu AR co-cultures than in the single culture of Pa AR and was found to be 20.12% and 13.29% higher than in the single culture of Pu AR. There was 1.27 fold and 1.81 fold increment of levels of caffeic acid derivatives with co-cultures(25.05 mg/g DW) when compared to single culture of Pu or Pa AR. Moreover, unique caffeic acid(0.12 mg/g DW) was detected by AR co-cultures compared to single culture.3. 3/4 MS was suitable for biomass production and secondary metabolites in Pa and Pu AR co-cultures.4. The optimal root biomass and secondary metabolite accumulation were achieved when Pu and Pa co-culture ratio was 3:4.5. The medium supplemented with 5%(w/v) sucrose were found to be suitable for inducing the accumulation of biomass and secondary metabolites(total polyphenols, flavonoids, total polysaccharides and caffeic acid derivatives). DPPH activity was correlated with metabolites accumulation.6. In the co-cultures, the best initial cultivation time was 0 day when Pa and Pu cultured simultaneously.