Comparison of yeast strains for batch ethanol fermentation of cheese-whey powder (CWP) solution

Aims: To test the suitability of cheese whey powder (CWP) solution for ethanol fermentation and to compare performances of different Kluyveromyces marxianus strains for ethanol fermentation from CWP solution. Methods and Results: Batch ethanol fermentation of cheese whey (CW), CWP and lactose solutions with the same initial sugar contents were compared by using two different K. marxianus strains and the CWP solution was found to be the most suitable substrate. CWP solution was fermented to ethanol using three different yeast strains and DSMZ-7239 was found to be the most suitable one yielding the highest rate and extent (3.3%, v/v) of ethanol formation. Conclusions: CWP solution and K. marxianus strain of DSMZ-7239 were found to be more suitable for ethanol fermentation with the highest ethanol yield when compared with the other substrates and the yeast strains tested. Significance and Impact of the Study: CWP can be used as a concentrated form of CW for ethanol fermentations with considerable advantages.