Enhanced productivity of biomass and bioactive compounds through bioreactor cultures of Eleutherococcus koreanum Nakai adventitious roots affected by medium salt strength

To develop a protocol of Eleutherococcus koreanum Nakai adventitious root culture for production of biomass and bioactive compounds through bioreactors, different strengths of Murashige and Skoog (MS) medium were tested. After 5 weeks of culture, root growth at low salt strengths (1/4, 1/2, and 3/4 MS) was better than that at high salt strengths (1 and 2 MS), and the highest fresh and dry weight was achieved at 1/2 MS. The roots cultured at strengths exceeding 1 MS showed physiological abnormalities such as shorter, thicker, and less numerous roots compared to other treatments. Strengths over 1 MS caused physical dehydration that stimulated proline accumulation in the roots and decreased water potential in the medium because of high osmotic stress. Total production of 5 target compounds (per 1 L medium), eleutheroside B and E, chlorogenic acid, total phenolics, and flavonoids, was decreased with increasing medium salt strength. However, the highest total production of eleutheroside B and E (per 1 L medium), the main bioactive compounds in this plant, were observed at 1/2 and 3/4 MS, respectively. Therefore, 1/2 MS is a suitable medium salt strength for both biomass and bioactive compound productions, and optimization of bioreactor culture conditions will benefit the large-scale production of E. koreanum-derived bioactive compounds for commercialization.

► Adventitious root culture is an attractive mean of bioactive compound production.
► Bioreactor culture expends exploitation on bioactive compounds for industries.
► In vitro conditions affect biomass and bioactive compound productions in bioreactors.
► The medium salt strength is one of the key factors that affect plant metabolites.
► Optimization of a culture protocol will benefit the pilot-scale production system.