Ethanol production by Saccharomyces cerevisiae and Kluyveromyces marxianus in the presence of orange-peel oil

Two ethanologenic yeasts, Saccharomyces cerevisiae and Kluyveromyces marxianus, were used to ferment sugar solutions modeling hydrolyzed Valencia orange peel waste at 37 degrees C. Orange stripper oil produced from orange peel was added in various amounts to determine its effect on ethanol production. The minimum peel oil concentration that inhibited ethanol production was determined after 24, 48 and 72 h and the two yeasts were compared to one another in terms of ethanol yield. Minimum inhibitory peel oil concentrations for ethanol production were 0.05% at 24 h, 0.10% at 48 h, and 0.15% at 72 h for both yeasts. S. cerevisiae produced more ethanol than K. marxianus at each time point.