In vitro adventitious roots of hemp in bioreactor culture to efficiently produce non-cannabinoids and cannabidiol phytochemicals

Hemp roots are used as a traditional Chinese medicine to treat fever, infection and arthritis. However, because tetrahydrocannabinol in leaves and inflorescences of hemp maybe be abused as an addicted drug, the hemp cultivation has always been a controversial legal issue in some countries, which limits the direct way to obtain hemp extracts. How to find an alternative approach to effectively obtain hemp phytochemicals has been the hotspot in the world. In vitro adventitious roots culture system is an excellent choice to obtain roots. This study proposed a method of adventitious roots from hemp in bioreactor (HBARs) for the first time through optimizing the culture conditions and preliminarily establishing the bioreactor scheme, then evaluated its effectiveness, substitutability, and feasibility. The results showed that the accumulations of saponins (48.75 ± 0.03 mg/g DW), polysaccharides (420.94 ± 0.01 mg/g DW) and cannabidiol (0.43 ± 0.01 mg/g DW) increased to the maximum in medium with 0.75× Murashige and Skoog, 2 mg/L indole-3butyric acid and 30 g/L sucrose. And their contents in HBARs increased 1.99, 12.78, and 2.19 folds to that in hemp plant, separately. Afterward, the numbers of cortical cells in transverse section of HBARs were more than those in petri dishes, and their volume was greatly increased than that in conical flask as well as the diameter of stele. This method exhibited high output, low cost, and practical properties. These results demonstrated that HBARs with high yields non-cannabinoids and cannabidiol could replace traditional planting methods to obtain hemp phytochemicals through large-scale culture.