Alcohol and Single Cell Protein Production by Kluyveromyces in Concentrated Whey Permeates with Reduced Ash

Five Kluyveromyces yeasts were grown in concentrated whey permeates under aerobic and anaerobic conditions to produce single cell protein and ethyl alcohol. Kluyveromyces fragilis NRRL Y 2415 produced the highest yield of alcohol, 9.1% vol/vol, and Kluyveromyces bulgaricus ATCC 1605 gave the highest yield of biomass, 13.5 mg/ml. High ash, apparently through sodium and potassium effects, inhibited production of biomass and alcohol. A .77% ash was optimum. Lactose utilization was more rapid under aerobic than anaerobic conditions. Ammonium sulfate and urea supplementation were without effect on yeast growth or were slightly inhibitory. A 1% peptone inclusion gave the highest biomass yield with minimum alcohol production.