THE EFFECTS OF MN2-PRODUCTION BY KLUYVEROMYCES-MARXIANUS IMB3 DURING GROWTH ON LACTOSE-CONTAINING MEDIA AT 45-DEGREES-C( ON ETHANOL)

It has previously been demonstrated that the thermotolerant yeast stra in, K. marxianus IMB3 is capable of growth and ethanol production on l actose containing media at 45 degrees C. Although the organism is capa ble of producing a beta-galactosidase, that enzyme has been shown to b e extremely thermolabile at 45 degrees C and this has been reflected i n reduced efficiencies with respect to conversion of lactose to ethano l. In this paper we demonstrate that addition of Mn2+ ions to enzyme p reparations contributes significantly to enzyme stability at 45 degree s C. We also demonstrate that addition of Mn2+ to fermentations result s in increased efficiency of conversion of lactose to ethanol at this temperature.