Enzymatic Synthesis of the Flavone Glucosides, Prunin and Isoquercetin, and the Aglycones, Naringenin and Quercetin, with Selective α-L-Rhamnosidase and β-D-Glucosidase Activities of Naringinase

The production of flavonoid glycosides by removing rhamnose from rutinosides can be accomplished through enzymatic catalysis. Naringinase is an enzyme complex, expressing both α -L-rhamnosidase and β -D-glucosidase activities, with application in glycosides hydrolysis. To produce monoglycosylated flavonoids with naringinase, the expression of β -D-glucosidase activity is not desirable leading to the need of expensive methods for α -L-rhamnosidase purification. Therefore, the main purpose of this study was the inactivation of β -D-glucosidase activity expressed by naringinase keeping α -L-rhamnosidase with a high retention activity. Response surface methodology (RSM) was used to evaluate the effects of temperature and pH on β -D-glucosidase inactivation. A selective inactivation of β -D-glucosidase activity of naringinase was achieved at 81.5°C and pH 3.9, keeping a very high residual activity of α -L-rhamnosidase (78%). This was a crucial achievement towards an easy and cheap production method of very expensive flavonoids, like prunin and isoquercetin starting from naringin and rutin, respectively.