INVERTASE FROM SACCHAROMYCES-CEREVISIAE - REVERSIBLE INACTIVATION BY COMPONENTS OF INDUSTRIAL MOLASSES MEDIA

Commercially available invertase (beta-D-fructofuranoside fructohydrol ase, E.C. 3.2.1.26) preparations from Saccharomyces cerevisiae are rev ersibly deactivated by high ethanol concentrations and by NaCl concent rations that occur in industrial molasses media. A significant differe nce in stability was found between the invertase activity of Baker's y east and of a highly specialized temperature-, ethanol-, and osmo-tole rant strain of S. cerevisiae. Deactivation of invertase is accompanied by dissociation of the glycosylated enzyme into subunits and is respo nsible for the limited maximum ethanol concentration of 80 g l(-1), wh ich is obtained in industrial yeast fermentations based on molasses.