Expression and purification of two Family GH31 α-glucosidases from Bacteroides thetaiotaomicron

► Assessed two α-glucosidases (BT_0339, BT_3299) from Bacteroides thetaiotaomicron. ► BT_0339 hydrolyzes isomaltase and maltoheptaose at the highest rate. ► BT_3299 hydrolyzes maltotetraose and maltoheptaose at the highest rate. ► Both enzymes were unable to utilize sucrose or lactose as a substrate. ► These enzymes reveal the ability that which this bacterium can utilize various starch glycans.