Biotransformation of hydroquinone by hairy roots of Brugmansia candida and effect of sugars and free-radical scavengers.

Hairy roots of Brugmansia candida were used to bioconvert hydroquinone into arbutin. The highest bioconversion, with the lowest damage to the cells, was attained when concentrations of 20-40 mg/L hydroquinone were used. Sugars (sucrose, glucose, mannitol, and sorbitol) at concentrations of 30-120 g/L enhanced bioconversion, and, of these, sucrose was the most effective. Two different free-radical scavengers were also tested: sodium benzoate and gallic acid. The first one diminished biotransformation efficiency; gallic acid did not affect biotransformation at all. Preliminary permeabilization treatments tested failed to liberate arbutin into the medium, and provoked a total loss in cell viability.