Evaluation of the potential production of ethanol by Candida zemplinina yeast with regard to beer fermentation

Candida zemplinina Y.01670 strain was evaluated to determine its potential for ethanol production and fermentative behavior with regard to potential use in beer fermentation. Experiments were carried out using malt wort with different adjuncts such as glucose syrup (dextrose equivalent 45), grape juice, and corn syrup with high fructose content. A 23 full factorial design was also used to evaluate the ethanol production when fermented in a medium containing a high sugar concentration, supplemented with soy lecithin, cholesterol, and Tween 80. The results showed that C. zemplinina Y.01670 strain allowed the production of variable ethanol content, which was dependent on the amount of fermentable sugars present in the medium. The use of corn syrup with a high content of fructose and grape juice as adjuncts yielded the highest ethanol production (up to 37.01 and 31.56 g/L, respectively). The results of the 23 full factorial design showed that the tested yeast strain is capable of producing up to 80.67 g/L of ethanol, with a yield of 0.46 ± 0.03 g of ethanol/g of sugar. Tween 80 effectively increased the production of ethanol when added at 0.5% vol/vol into the fermentation medium. These findings are considered promising for the potential use of Candida zemplinina Y.01670 in beer fermentation.