Vol.:(0123456789) 1 3 Plant Cell, Tissue and Organ Culture (PCTOC) https://doi.org/10.1007/s11240-020-01961-9 ORIGINAL ARTICLE Culture condition optimization and FT‑IR analysis of Polygonum multiflorum Thunb. adventitious root cultures grown in an air‑lift bioreactor system Thanh‑Tam Ho 1,2  · Kim‑Cuong Le 3,4  · Suk‑Weon Kim 5  · So‑Young Park 3 Received: 22 July 2020 / Accepted: 24 October 2020 © Springer Nature B.V. 2020 Abstract Bioreactor cultures have been used for biomass production and bioactive compounds accumulation in adventitious root cultures of medicinal plants. In this study, we evaluated the efects of diferent auxin types [indole-3-butyric acid (IBA) and 1-naphthale- neacetic acid (NAA)] and concentrations (0.5, 1.0, 2.0 and 4.0 mg·L −1 ), Murashige and Skoog (MS) medium salt strength (0.25, 0.5, 0.75, 1.0, 1.5 and 2X), and sucrose concentrations (0, 1.5, 3, 5, 7 and 10%) on Polygonum multiflorum Thunb. adventitious root cultures in a 3-L balloon-type bubble bioreactor (BTBB). IBA (1, 2, and 4 mg·L −1 ) was more efective than NAA in promoting root growth. Additionally, low MS salt strength (0.25 and 0.5X MS) increased the accumulation of total phenolics and favonoids but reduced biomass accumulation. Four weeks of culture in full-strength MS medium supplemented with 2 mg·L −1 IBA and 5% sucrose resulted in the highest root biomass [98.46 g·L −1 fresh weight (FW); 13.46 g·L −1 dry weight (DW)] and bioactive compounds accumulation (total phenolics compounds, 53.08 mg·g −1 DW; total favonoids, 25.10 mg·g −1 DW). To determine whether metabolic fngerprinting of whole-cell extracts could be used to compare metabolic equivalence of P. multiflorum root samples, we treated adventitious roots with diferent culture conditions, and analyzed the treated adventitious roots and natural roots by Fourier transform infrared (FT-IR) spectroscopy. The results showed that the metabolic pattern of adventitious root sam- ples was similar under diferent culture conditions; however, these samples could be discriminated from each other in pilot-scale bioreactors. Overall, our study provides useful information for industrial-scale cultivation of P. multiflorum adventitious roots. Key message The optimum condition for bioreactor culture of Polygonum multiforum is full-strength MS medium supplemented with 2 mg·L-1 IBA and 5% sucrose after 4 weeks of culture. FT-IR analysis can rapidly discriminate among root samples based on total metabolite equivalence. Keywords Adventitious root · Bioactive compounds · Bioreactor culture · FT-IR · Root biomass Communicated by Wagner Campos Otoni. Electronic supplementary material The online version of this article (https://doi.org/10.1007/s11240-020-01961-9) contains supplementary material, which is available to authorized users. * So-Young Park soypark7@cbnu.ac.kr 1 Institute for Global Health Innovations, Duy Tan University, Da Nang 550000, Vietnam 2 Faculty of Pharmacy, Duy Tan University, Da Nang 550000, Vietnam 3 Department of Horticulture, Division of Animal, Horticultural and Food Sciences, Chungbuk National University, Cheongju 28644, Republic of Korea 4 Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, 901 83 Umeå, Sweden 5 Biological Resource Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Jeongeup 56212, Republic of Korea