A novel secoisolariciresinol diglucoside (SDG)-beta-glucosidase from Bacillus altitudinis HK02 is capable of deglycating phenolic glycosides from flaxseed. Three glycosides, SDG, coumaric acid glucoside (CAF) and ferulic acid glucoside (FAG), were purified from flaxseed and deglycated into aglycones by the prepared glycosidase. The deglycation rates of these phenolic glycosides were dependent on the number of sugar moieties on the glycones. The deglycation of SDG with two glucose molecules into secoisolariciresinol (SECO) occurred after both CAG and FAG were completely consumed. The efficiency of the enzymatic deglycation of these three glycosides could reach approximately 100%. The addition of defatted flaxseed flour or alkali-ethanol extract to the media enhanced enzyme activities and accelerated the conversion rate of SDG; however, carbon sources such as glucose, sucrose, fructose and mannitol significantly inhibited enzyme activities. The novel SDG-beta-glucosidase was proposed as an inducible enzyme regulated by a variety of inducers or catabolites. (C) 2015 Elsevier Ltd. All rights reserved.