초록
<P>A novel β-glucosidase named BglW5 from <I>Gongronella</I> sp. was isolated, purified, and characterized for the first time. Under solid state fermentation, the yield of BglW5 was 49.9 U/g fermented medium. BglW5 was stable over a wide pH range of 3.0–8.5 and retained more than 50% of its maximal activity after incubation at 25 °C for 96 h. The half-lives of BglW5 were 20 h at 60 °C, and 1 h at 70 °C. The activity of BglW5 was stimulated by xylose and fructose at concentrations up to 500 mM, with maximal stimulatory effect of 1.6-fold and 2.2-fold, respectively. BglW5 converted isoflavone glycosides to aglycones, with a hydrolysis rate of 96.2% for daidzin and 96.7% for genistin. The productivities were 1.5 mmol L<SUP>–1</SUP> h<SUP>–1</SUP> for daidzein and 1.23 mmol L<SUP>–1</SUP> h<SUP>–1</SUP> for genistein, respectively. These features suggest that BglW5 has great application potential in the hydrolysis of soybean isoflavone glycosides.</P><P><B>Graphic Abstract</B><BR><IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jafcau/2014/jafcau.2014.62.issue-48/jf502850z/production/images/medium/jf-2014-02850z_0006.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/jf502850z'>ACS Electronic Supporting Info</A></P>