Effects of nitrogen source and phosphate concentration on biomass and metabolites accumulation in adventitious root culture of Glycyrrhiza uralensis Fisch

We investigated the influence of ammonia/nitrate ratio and phosphate concentration on biomass and accumulation of metabolites in adventitious roots of Glycyrrhiza uralensis Fisch. A NH4 +/NO3 − ratio of 10:20 was optimal for the production of biomass (0.30 g dry weight) as well as polysaccharide (18.98 mg g−1) and glycyrrhetinic acid (0.31 mg g−1). The content of glycyrrhizic acid (0.47 mg g−1) and flavonoid (8.11 mg g−1) reached the optimum at an ammonia/nitrate ratio of 15:15 and 20:10, respectively. In case of phosphate concentration, a higher growth rate (9.18) and content of polysaccharide (15.66 mg g−1) was obtained at 1.25 mM phosphate concentration. However, 0.625 mM phosphate was favorable for the content of flavonoid (7.54 mg g−1) and glycyrrhizic acid (0.57 mg g−1). The content of glycyrrhetinic acid (0.32 mg g−1) reached the peak when treated with 0.3125 mM phosphate. A scale-up culture of adventitious roots was established using a balloon-type bubble bioreactor (BTBB). Maximum growth rates of 25.95- and 22.44-fold were obtained in 3 and 5 L BTBBs, respectively, which was higher than that in 0.5 L shake flask (18.36). The contents of flavonoid (7.60 mg g−1) and polysaccharide (15.09 mg g−1) reached the peak in 5 L and 3 L BTBB, respectively. The contents of glycyrrhizic and glycyrrhetinic acid were a little higher than that in BTBBs.