Unusual Non-Saccharomyces Yeasts Isolated from Unripened Grapes without Antifungal Treatments

Abstract

There a lot of studies including the use of non-Saccharomyces yeasts in the process of wine fermentation. The attention is focused on the first steps of fermentation. However, the processes and changes that the non-Saccharomyces yeast populations may have suffered during the different stages of grape berry ripening, caused by several environmental factors, including antifungal treatments, have not been considered in depth. In our study, we have monitored the population dynamics of non-Saccharomyces yeasts during the ripening process, both with biochemical identification systems (API 20C AUX and API ID 32C), molecular techniques (RFLP-PCR) and enzymatic analyses. Some unusual non-Saccharomyces yeasts have been identified (Metschnikowia pulcherrima, Aureobasidium pullulans, Cryptococcus sp. and Rhodotorula mucilaginosa). These yeasts could be affected by antifungal treatments used in wineries, and this fact could explain the novelty involved in their isolation and identification. These yeasts can be a novel source for novel biotechnological uses to be explored in future work.

Culturable Yeast Diversity of Grape Berries from Vitis vinifera ssp. sylvestris (Gmelin) Hegi

“…However, from the enological and biotechnological perspectives, some yeast species are usually present during the fermentation process. After processing, three groups of non-Saccharomyces yeasts can be found in the first stages of grape must fermentation [62], during which they proliferate due to their lower tolerance to ethanol: aerobic yeasts (e.g., yeasts of genera Pichia, Rhodotorula, and Cryptococcus), yeasts with low or medium fermentation ability (e.g., genera Hanseniaspora and Metschnikowia), and yeasts with fermentative capacity (Lachancea, Zygosaccharomyces, and Torulaspora). These yeasts are then gradually replaced by the ethanol-tolerant yeast S. cerevisiae [62,63].…”

Production of kurut (kurt) using probiotic Lacticaseibacillus rhamnosus GG strain in combination with a yeast isolated from Kazakhstan kurut

“…Thus, many examinations have already been piloted to produce LGGenriched products, such as Camembert-type cheese, yoghurt, buttermilk, salad dressing, sausage, and kefir (Rodgers, 2001;Galli et al, 2019;Yousefvand et al, 2022). It has been reported that C. laurentii yeast function as a biocontrol agent against fruit pathogens (Mateo et al, 2020). In addition, this yeast was isolated from Zimbabwean traditional fermented milks (Gadaga et al, 2000).…”