Resveratrol, an ingredient of traditional Chinese medicine, has beneficial effects on human health and huge potential for application in modern medicine. Polydatin is extracted from plants and then deglycosylated into resveratrol; enzymatic methods are preferred for this reaction. In this study, a β-D-glucosidase from Sphingomonas showed high efficiency in transforming polydatin into resveratrol and was tolerant toward organic solvents. Applying this enzyme in a biphasic transformation system resulted in 95.3% conversion of 20% concentration crude polydatin to resveratrol in 4 h. We thus report a new method for high-efficiency, clean production of resveratrol.

Although β-xylosidases with xylanase activity are preferential for the hydrolysis of xylan and production of xylitol, reports on their use are scarce. In this study, a multifunctional β-xylosidase (XYL4) was identified. In addition to β-xylosidase activity, XYL4 also exhibited xylanase and low α-arabinosidase activity. The enzyme was able to hydrolyze bagasse xylan, oat spelt xylan, birchwood xylan, beechwood xylan, and corncob xylan, and showed the highest hydrolysis activity for corncob xylan. Structural modeling analysis indicated that XYL4 had an additional PA14 domain, which may play a key role in binding xylan substrates. Moreover, XYL4 was used to hydrolyze corncob xylan to produce xylose. When enzymatic hydrolysis and whole-cell catalysis were used to hydrolyze 100 g/L of corncob xylan, the xylose yields were 60.26% and 35.85%, respectively. Then, the Candida tropicalis was inoculated with the above hydrolysates for fermentation to produce xylitol. Using enzymatic hydrolysis and whole-cell catalysis, xylitol yields of 77.56% and 73.67% were obtained by C. tropicalis after the optimization of fermentation, respectively.