EXPLORING THE METABOLIC AND PHENOTYPIC DIVERSITY OF INDIGENOUS YEASTS ISOLATED FROM GREEK WINE

Abstract

Climate change leads to even more hostile and stressful for the wine microorganism conditions and consequently issues with fermentation rate progression and off-character formation are frequently observed. The objective of the current research was to classify a great collection of yeast isolates from Greek wines based on their technological properties with oenological interest. Towards this direction, fourteen spontaneously fermented wines from different regions of Greece were collected for further yeast typing. The yeast isolates were subjected in molecular analyses and identification at species level. Random Amplified Polymorphic DNA (RAPD) genomic fingerprinting with the oligo-nucleotide primer M13 was used, combined with Matrix Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry (MALDI-TOF MS) technique. All yeast isolates were scrutinized for their sensitivity to killer toxin, production of metabolites such as acetic acid and H₂S, enzymatic activity of β-glucosidase and resistance to different concentrations of the antimicrobial agents; SO₂. Qualitative data were statistically treated by homogeneity of variances, one sample Kolmogorov-Smirnov and off between-subjects effects tests. According to our results, among the 190 isolates, S. cerevisiae was the most dominant species (83,5%) while some less common non-Saccharomyces species such as Trigonopsis californica, Priceomyces carsonii, Zygo saccharomyces bailii, Brettanomyces bruxellensis and Pichia manshurica were identified in minor abundancies. Moreover, based on phenotypic typing, the majority of isolates were neutral to killer toxin test and exhibited low acetic acid production. Additionally, statistically significant differences were observed between the different levels of H₂S production in terms of sample origin and yeast species. Finally, Hierarchical Cluster Analysis revealed the presence of four yeast groups based on phenotypic fingerprinting. This study proposed a fast preselection of wine autochthonous yeast with oenological potential using a simple phenotypic-based methodology.

Acknowledgements: This research has been co-financed by the European Union and Greek national funds through the Operational Program Competitiveness, Entrepreneurship and Innovation, under the call ”
Greece – Israel Call for Proposals for Joint R&D Projects 2019″(project code: T10ΔIΣ-00060).