Comparison between various commercial sources of almond β-glucosidase for the production of alkyl glucosides

Ten different almond β-glucosidases, from eight commercial sources, were compared for their capacity to produce octyl glucoside by direct condensation from glucose and octanol, with and without added dimethyl formamide (DMF) in the octanol media. All the preparations tested catalyzed the synthesis of octyl glucoside, at rates ranging from 0.002 to 0.012 μmol/h, per added unit of enzyme, one unit being defined as the amount of enzyme catalyzing the hydrolysis of 1 μmol of p-nitrophenyl-β-d-glucopyranoside (p-NPG) per minute at 50 °C at pH 4.8. However, none of the preparations showed strong activation by DMF, contrary to what has been previously observed. Some preparations were slightly activated (two-fold maximum) by 10% DMF. It appears that the enzymes with the lowest specific activity for the hydrolysis of p-NPG were activated more strongly by DMF than the most active preparations.