Evaluating fermentation characteristics of Kazachstania spp. and their potential influence on wine quality

The current study is the first one to demonstrate the wine fermentation potential of members of several species of the genus Kazachstania including strains derived from grape must. The fermentation characteristics were evaluated in synthetic grape juice medium and in Sauvignon blanc. Our data show that none of the species evaluated could ferment to dryness in monoculture fermentations. However, at least 75% of the sugar was consumed before the fermentations got stuck. In mixed-culture fermentations with Saccharomyces cerevisiae diverse aroma profiles were evident especially in Sauvignon blanc fermentations. Four distinct potential aroma associations were identified: (i) Kazachstania solicola —vinegar and solvent-like, (ii) Kazachstania hellenica —spirituous, cheesy, (iii) Kazachstania aerobia CBS—fruity, floral (iv) K. aerobia IWBT, Kazachstania unispora and Kazachstania servazii —rancid, harsh. Furthermore, strain variation was apparent as the two K. aerobia strains displayed distinct karyotypes and aroma potential. Our data show that although members of the genus Kazachstania are typically encountered at low frequency in grape must, some of the species have positive aroma attributes that should be explored further.