Efficient Production of Ethanol from Saccharified Crops Mixed with Cheese Whey by the Flex Yeast Kluyveromyces marxianus KD-15

Ethanol production from a mixture of wheat flour or potato tubers and cheese whey was examined using the flex yeast Kluyveromyces marxianus KD-15, a 2-deoxyglucose-resistant mutant of strain NBRC 1963 that can produce ethanol from sugar beet thick juice diluted with whey. Strain KD-15 simultaneously converted glucose and lactose to ethanol within 48 h, in media containing 10.0% to 15.0% (w/v) total sugars from saccharified filtrate and whey. For efficient production of ethanol from 15.0% (w/v) total sugars, KD-15 cells were collected after fermentation and inoculated into fresh media. Batch fermentation was successfully repeated at least ten times in medium composed of saccharified potato tubers mixed with whey. Yeast cells began to convert all the sugars to ethanol within 24 h, accompanied by cell propagation after the third batch