Abstract
The fermentation ability of a strain of Kluyveromyces fragilis, already selected for rapid lactose-fermenting capability, was improved dramatically by the addition of unsaturated fatty acids and ergosterol to the medium. The fermentation time of a 20% whey-lactose medium was decreased from over 90 h to less than 60 h. The lipids were shown to be taken up by the organism, and the effects on specific growth rate and biomass production were determined.