Formation of gal-sorbitol during lactose hydrolysis with β-galactosidase

The objective of the work was to determine the effect of selected parameters: content of dry matter in reaction mixture, temperature, pH and concentration of NaCl on the enzymic synthesis of gal-sorbitol with P-galactosidase from Kluyveromyces lactis. The highest content of gal-sorbitol (16.8% w/w in dry matter) was obtained using 35% (w/v) solution of lactose and sorbitol (1: 1). Temperature had a minimal effect on the amount of the sorbitol derivative synthesised. An increase in pH from 6.5 to 9.0 caused approximately a 9% increase in the amount of gal-sorbitol. The presence of 0.25-0.75 M NaCl caused approximately an 11% increase in the amount of the product synthesised. An increase in pH and an addition of NaCl caused an increase in the process duration. (c) 2005 Elsevier Ltd. All rights reserved.