Well done to Lidia and Chris and massive thank you to Louise Gourlay (excellent crystallographer at the University of Milan) for this great work on the extraction of isofavones from soy flour with a new glycosyl hydrolase.
β-Glucosidases are used in the food industry to hydrolyse glycosidic bonds in complex sugars, with enzymes sourced from extremophiles better able to tolerate the process conditions. In this work, a novel β-glycosidase from the acidophilic organism Alicyclobacillus herbarius was cloned and heterologously expressed in E. coli BL21 (DE3). AheGH1 was stable over a broad range of pH values (5-11) and temperatures (4 ºC-55 ºC). The enzyme exhibited excellent tolerance to fructose and good tolerance to glucose, retaining 65% activity in the presence of 10% (w/v) glucose. It also tolerated organic solvents, some of which appeared to have a stimulating effect, in particular ethanol with a 1.7-fold increase in activity at 10% (v/v). The enzyme was then applied for the cleavage of isoflavone from isoflavone glucosides in an ethanolic extract of soy flour, to produce soy isoflavones which constitute a valuable food supplement, achieving full conversion within 15 min at 30 °C.
Read the full paper here