Hydroponic combined with natural or forced root permeabilization: a promising technique for plant secondary metabolite production

In order to evaluate a possible new method for the production of plant secondary compounds at industrial scale, Datura innoxia Mill. plants were cultivated in hydroponic conditions before being permeabilized with Tween20. High concentrations (10–80 mg/l) of tropane alkaloids (TA) (i.e. hyoscyamine and scopolamine) could then be detected in the nutrient solution. After having their roots rinsed, all the plants were able to survive and some of them were permeabilized a second and a third time without loss of viability. This article also shows the positive effects of D. innoxia Mill. permeabilization with various Tween20 treatments such as doses (1, 2, 3 or 5% V/V), duration (12, 24 or 48 h) and the addition of tropane alkaloid precursors (phenylalanine and ornithine), leading to a 10–80 mg/l release of TA in the nutrient solution. A small scale pilot was developed and allowed the production of 180 mg of hyoscyamine and scopolamine in 27 days. In order to evaluate the potential of this method, it was carried out on other plants: permeabilization of hydroponic Taxus baccata. plants led to a 10-fold increase of Paclitaxel in the nutrient solution, whereas for Ruta graveolens, possible effects of Tween20 were hidden by a naturally high release of furanocoumarins in the medium.