Diversity and oenological characterization of indigenous Saccharomyces cerevisiae associated with Žilavka grapes

Abstract

The aim of this research was to identify the Saccharomyces spp. associated with Ž ilavka grapes and to evaluate their enzymatic activities, H 2 S production and micro-fermentation performance. For this purpose, a total of 143 yeast strains isolated from three production areas of the Mostar wine region (Bosnia and Herzegovina) were studied and analysed. Firstly, yeasts were identified to genus level by growth on WL nutrient agar and the test of assimilation of lysine. Later, molecular identification at species level was carried out with RFLP analysis of 18S rDNA ? ITS region, and at strain level with microsatelliteprimed PCR (MSP-PCR). At physiological level yeast strains were grouped into different clusters by means of the Joining-Tree-Clustering-Method. All yeasts tested were identified as S. cerevisiae, resulting a total of 18 different strains. All of the investigated strains produced hydrogen sulphide, 89% were able to complete the fermentation, and none of them was able to synthesize killer toxins. Since enzymes play a very important role in wine aroma development, it was very encouraging that 33% of the strains were able to synthesize pectinolytic enzyme but only one produced b-glucosidase. In the second part of the selection process two indigenous strains were compared with commercial yeast in a microvinification and Ž ilavka wines with different profiles of volatiles were obtained. This research represents a first step in the selection of indigenous yeast strains from the Mostar region with the goal of maintaining the specific organoleptic characteristics of Ž ilavka wine.

Ochratoxin A removal by Saccharomyces cerevisiae strains: effect of wine‐related physicochemical factors

“…Colour of biomass: 0, white (no hydrogen sulfide production); 1, cream (low production); 2, light brown (medium production); 3, dark brown (high production) …”

“…The following assays were performed: hydrogen sulfide production; interaction with phenolic compounds; amino acid decarboxylation (histidine, tyrosine, phenylalanine, tryptophan, lysine, leucine, ornithine, arginine); β ‐ d ‐glucosidase activity on esculin; pectolytic, xylanase and protease activities; ester hydrolase and glycosidase activities; β ‐ d ‐xylosidase activity …”

Selection of Autochthonous Saccharomyces cerevisiae Strains as Wine Starters Using a Polyphasic Approach and Ochratoxin a Removal

“…The ability to produce hydrogen sulfide was tested by using a qualitative method based on colony appearance on BiGGY agar (33). Decarboxylase activity was determined using the method of Nikolaou et al (31); histidine, tyrosine, phenylalanine, tryptophane, lysine, leucine, ornithine, and arginine were used as precursor amino acids.…”

A Focus on Quality and Safety Traits of Saccharomyces cerevisiae Isolated from Uva di Troia Grape Variety

“…Yeasts were streaked onto the surface of BIGGY agar medium (Oxoid; Orlić and others ); the plates were incubated at 25 °C for 3 d. The color of the streak (cream, light brown or dark brown) was used as an indirect index to asses H 2 S: low production (cream; code 1); medium production (light brown; code 2); high production (dark brown; code 3; Petruzzi and others ).…”