Co-cultures of shoots and hairy roots of Genista tinctoria L. for synthesis and biotransformation of large amounts of phytoestrogens

Abstract

Shoot and hairy root Genista tinctoria co-culture was established in Schenk and Hildebrandt medium supplemented with 24.6 μmol l −1 indole-3-butyric acid (IBA) to produce large amounts of isoflavones of phytoestrogenic activity. The different tissue inoculation ratios were tested to achieve the best growth of G. tinctoria shoots and hairy roots in the co-culture system. In the co-culture, hairy roots produced large amounts of a single isoflavone—isoliquiritigenin (2473.8 mg/100 g dry weight (DW)), which is a daidzein precursor absent in the intact plant. Owing to the addition of abscisic acid (37.8 μmol l −1—on day 42), isoliquiritigenin was almost completely released into the growth medium, from which it was used by the shoots to produce significant amounts of daidzin and daidzein. G. tinctoria shoots in a co-culture system, like in classic single cultures, maintained the ability to produce significant amounts of genistin (6941.5 mg/100 g DW) and its derivatives. At the same time, as a result of the described bioconversion of isoliquiritigenin, they synthesised 38 times more daidzin than the intact plant (1647.5 mg/100 g DW). This result suggests that G. tinctoria co-culture may be used to produce large amounts of isoflavone phytoestrogens. A prototype basket-bubble bioreactor was designed and built to upgrade the scale of the G. tinctoria co-culture. The new device significantly improved the growth parameters and the productivity of both tissues.