Aim: To evaluate the coumarate descarboxylase (CD) and vinylphenol reductase (VR) activities in Dekkera bruxellensis isolates and study their relationship to the growth rate, protein profile and random amplified polymorphic DNA (RAPD) molecular pattern. Methods and Results: CD and VR activities were quantified, as well, the growth rate, intracellular protein profile and molecular analysis (RAPD) were determined in 12 isolates of D. bruxellensis. All the isolates studied showed CD activity, but only some showed VR activity. Those isolates with the greatest growth rate did not present a different protein profile from the others. The FASC showed a relationship between RAPD molecular patterns and VR activity. Conclusion: CD activity is common to all of the D. bruxellensis isolates. This was not the case with VR activity, which was detected at a low percentage in the analysed micro-organisms. A correlation was observed between VR activity and the RAPD patterns. Significance and Impact of the Study: This is the first study that quantifies the CD and VR enzyme activities in D. bruxellensis, demonstrating that these activities are not present in all isolates of this yeast.

Dekkera bruxellensis is the major contaminant yeast in the wine industry worldwide. Here, we present the draft genome sequence of D. bruxellensisLAMAP

Currently, there is a worldwide trend toward the food consumption without the use of preservatives. For this reason, biocontrols have emerged as a natural option to replace preservatives. We identify and select native wine yeasts with antimicrobial activity (AA) that work against pathogenic bacteria of food importance. We evaluated the antimicrobial capacity of 103 yeast against Salmonella typhimurium, Listeria monocytogenes, and Escherichia coli, by measuring the growth inhibition. AA was qualitatively determined by measuring the inhibition zone diameter accompanied by death zone of target cells. Results revealed that nine yeast strains showed AA against the three pathogens, being mainly of the genera Pichia, Candida, and Saccharomyces. To determine the type of AA, the viability was assessed by the method of SYTOX Green®. The results suggest that yeast exhibit AA bactericidal type. Thus, the use of yeasts arises as a natural and safe for the biocontrol of bacterial growth alternative.

Torulaspora delbrueckiiis a yeast species typically present in the early stages of the fermentation process.T. delbrueckiipositively modifies the aromatic properties of wines. However, its contribution to the final quality of the wine is restricted by its low tolerance to ethanol.T. delbrueckiiis capable of fermenting and tolerating an ethanol concentration ranging from 7.4% (v/v) to slightly higher than 9% (v/v). For this reason, it cannot complete fermentation, when alcohol reach levels higher than 12% (v/v), limiting their use in the industry. The objective of this work was to obtain new variants ofT. delbrueckiiwith improved resistance to ethanol through adaptive laboratory evolution. Variants capable of tolerating ethanol levels of 11.5% (v/v) were obtained. These presented improved kinetic parameters, and additionally showed an increase in resistance to SO₂in ethanol compared to the original strain. Co-inoculated fermentations were performed with the original strain (FTd/Sc) and with the evolved strain (FTdF/Sc), in addition to a control fermentation using onlySaccharomyces cerevisiaeEC1118 (FSc). The results obtained show that FTdF/Sc present higher levels of 2-Ethylhexanol, compared to FTd/Sc and FSc. Furthermore, FTdF/Sc presents higher levels of total alcohols, total aldehydes, total phenolic derivatives, and total sulfur compounds with significant differences with FSc. These results provide aT. delbrueckiiYCPUC10-F yeast with higher resistance to ethanol, which can be present throughout the fermentation process and be used in co-inoculated fermentations. This would positively impact the performance ofT. delbrueckiiby allowing it to be present not only in the early stages of fermentation but to remain until the end of fermentation.