Study on β-galactosidase isolation, purification and optimization of lactose hydrolysis in whey for production of instant energy drink

Abstract

Four yeast cultures, Kluyveromyces marxianus, Kluyveromyces fragilis, Saccharomyces marxianus and Saccharomyces fragilis, were selected for isolation of ?-galactosidase. Enzyme activity was measured for all four strains and found Kluyveromyces marxianus (177 ONPG unit/ml) to have the highest activity. Experimental whey was hydrolyzed with the enzyme extracted from K. marxianus, and the concentrations of enzyme used were 0.5, 1.0, 1.5, 2.0 and 2.5 ml of enzyme per litre of whey. The percentage of lactose hydrolysis was found to be a maximum of 80% in 60 minutes time for the enzyme concentration of 2.0 ml/ litre of whey. © 2009 The Berkeley Electronic Press. All rights reserved.