Isolation and Identification of Lactose-Degrading Yeasts and Characterisation of Their Fermentation-Related Ability to Produce Ethanol

Kefir is traditionally produced by fermenting cow’s milk using kefir grains as a starter culture. As the viability of microbes within limited and preparing for fermentation laborious, here, single that ferments lactose produces ethanol developed. For this purpose, it important to isolate yeasts can ferment subsequently produce alcohol. This study aimed identify from characterise their ability starters kefir. Based on morphological physiological evaluations, 15 presumptive yeast isolates were obtained, 10 which grew well lactose-containing media. Those able grow only carbon sources subjected molecular identification based internal transcribed spacer (ITS) 5.8 rDNA PCR technology. Molecular confirmed four isolates—namely, KFA 3, 7, 9 KFB 1—as belonging Kluyveromyces marxianus. The batch data these strains fitted logistic model obtain carrying capacity coefficients strain performances compared. kinetic modelling revealed had highest values coefficient, biomass yield product yield, indicating that, among K. marxianus strains, was superior due its relatively fast growth good productivity.