Alcohol production by Yeast in whey ultrafiltrate

Deproteinized ultrafiltrate whey-a by-product of cheese manufacture-has become a serious pollution problem. The major component of ultrafiltrate whey solids is lactose. Utilization of whey as a fermentation substrate has been studied extensively. Different processes utilize whey as a substrate for the production of alcohol,' and beverage^.^ A major problem for the production of alcohol has been the fact that relatively few yeast are able to ferment lactose. Yoo6 found that a strain of Kluyveromyces fragilis was the most efficient lactose fermenter when the dry weight of the whey is less than 10%. However, only 55% of the lactose was fermented. O'Leary et al.'.8 investigated the potential use of lactose-hydrolyzed whey as a fermentation medium for alcohol production by Saccharomyces cerevisiae; they showed that a diauxic fermentation pattern occurred with the result that the fermentation time increased beyond that of conventional whey. We have shown in a survey of 40 lactose-assimilating yeasts that various strains produced a high alcohol yield