BIOTECHNOLOGICAL PRODUCTS AND PROCESS ENGINEERING Improvement of biosynthesis and accumulation of bioactive compounds by elicitation in adventitious root cultures of Polygonum multiflorum Thanh-Tam Ho 1 & Jong-Du Lee 2 & Cheol-Seung Jeong 1 & Kee-Yoeup Paek 1 & So-Young Park 1 Received: 11 September 2017 /Revised: 19 October 2017 /Accepted: 3 November 2017 # Springer-Verlag GmbH Germany, part of Springer Nature 2017 Abstract We examined the effects of abiotic (methyl jasmonate [MeJA] and salicylic acid [SA]) and biotic (yeast extract and chitosan) elicitors for improvement of bioactive compounds production on adventitious root cultures in Polygonum multiflorum. The application of yeast extract re- sulted in significantly (p ≤ 0.05) higher dry root biomass (9.98 g/L) and relative growth rate versus the control. Cultures treated with abiotic elicitors showed higher percent- age of dry weight than the other samples. Low concentrations of all elicitors (50 μM MeJA and SA, and 50 mg/L yeast extract) improved secondary metabolite production except for chitosan, whose performance was worse than that of the control. HPLC analysis of various bioactive compounds re- vealed significantly higher elicitation efficiency for MeJA than for the other treatments, with an approximately 2-fold increase in root dry weight (22.08 mg/g DW) under 50 μM MeJA treatment versus the control (10.35 mg/g DW). We also investigated the feasibility of scaling up the production pro- cess by comparing shake flask cultures with 3- and 5-L bal- loon type bubble bioreactors (BTBB) using 50 μM MeJA as an elicitor. Growth and metabolite accumulation increased in BTBB compared with shake flask cultures. We detected a non-significant difference in biomass productivity between 3 and 5-L BTBB, but the efficiency of bioactive compound accumulation decreased with increasing volume. These find- ings will be useful for developing a pilot-scale P. multiflorum adventitious root cultivation process for high biomass and bioactive compound production to meet the demands for nat- ural ingredients by the pharmaceutical and cosmetic industries without affecting the natural habitat of this plant. Keywords Abiotic elicitor . Adventitious root biomass . Phenolic compounds . Biotic elicitor . Polygonum multiflorum Introduction Polygonum multiflorum Thunb., a perennial vine native to China, has enormous ethno-pharmacological significance, which has led to its inclusion in Chinese Pharmacopoeia (Thiruvengadam et al. 2014; Bounda and Feng 2015). The root extracts of this herb were traditionally used as a hair dye, a liver and kidney tonic, and an anti-aging ingredient in China, Korea, and Japan (Han et al. 2015). Various investiga- tions have also demonstrated a much wider role for bioactive compounds from P. multiflorum, which have anti-tumor, anti- diabetic, and anti-hyperlipidemic properties, besides being ef- fective in the management of serious disorders such as cardio- metabolic issues and inflammation (Hong et al. 1994; Lin et al. 2003). This plant species is widely distributed around the globe and is used in a number of herbal drugs. P. multiflorum roots contain an array of phenolic compounds including stilbenes, anthraquinones, and phospholipids (Yi et al. 2007). Since roots are the main source material for the extraction of secondary metabolites, the P. multiflorum popu- lation in its natural habitat is adversely affected when the plants are uprooted. Also, the demand for such natural ingre- dients for therapeutic and personal care purposes has been escalating. These metabolites are produced at very low levels, which depend on both the physiology and developmental stage of the plant (Rao and Ravishankar 2002). Besides low * So-Young Park soypark7@cbnu.ac.kr 1 Department of Horticultural Science, Division of Animal, Horticulture and Food Sciences, Chungbuk National University, Cheongju 28644, Republic of Korea 2 Hankookshinyak Pharmaceutical Co. Ltd., Nonsan Chungnam 28433, Republic of Korea Appl Microbiol Biotechnol https://doi.org/10.1007/s00253-017-8629-2