Professor Song Xin from Shandong University reported biotransformation of piceid in Polygonum cuspidatum to resveratrol by immobilized β-glucosidase on 2013CNIC.

β-glucosidase, a rate-limiting enzyme in cellulose degradation enzyme system, can hydrolyze cellobiose to glucose. β-glucosidase is gained through fermentation of microorganisms, filamentous fungi, especially Aspergillus and Penicillum. But low activity of β-glucosidase-producing strains become the bottleneck of industrial applications of β-glucosidase.

Resveratrol, 3,4,5-trans-trihydroxystilbene, a naturally occurring stilbene, is rich in over 70 plants such as Vitaceae, Liliaceae and Leguminosae. But most of resveratrol in plants presents in the form of glycosides (2-4%), and the content of free resveratrol is low (0.1-0.45%). Resveratrol is considered to have a number of benefits, including anticancer, anti-atherogenic, anti-oxidative, anti-inflammatory, anti-microbial and estrogenic activity, so it is potential to be widely applied in cosmetics, pharmaceuticals and health care products, etc.

There are many methods to gain resveratrol, primarily including extraction from plants, cultivation of plant cells, synthesis with chemical methods, synthesis catalyzed by a series of enzymes, expression by gene-engineered microorganisms, transformation of glycosidically-bound resveratrol into free resveratrol by enzymatic hydrolysis.

Glycosidically-bound resveratrol was transformed into free resveratrol traditionally by acid or alkaline hydrolysis. Now, the process can be catalyzed by β-glucosidase. However, the β-glucosidase activities of currently-known cellulase-producing strains are generally low, which limits its wide applications. Professor Song leads his team to separate and purify several β-glucosidases in Penicillum oxalicum, screen high β-glucosidase-producing strains, and then make β-glucosidase immobilized. Professor Song detailed his work on immobilization, transformation and purification on 2013 CNIC. He and his team have gained application patent for the study.

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