Maria Jose Valera, Valentina Olivera, Eduardo Boido, Eduardo Dellacassa, and Francisco Carrau*
*Universidad de la Republica, Av. Gral. Flores 2124, 11800, Uruguay (fcarrau@fq.edu.uy)

Hanseniaspora species are the main yeasts isolated from grapes and grape musts. The genus has two clear technological clusters, the fruit group and the fermentation group, based on genetic and phenotypic characterization. Among the Hanseniaspora species belonging to the latter, H. osmophila and H. vineae have been found in spontaneous fermentations of grape must. These yeasts are characterized by their increased capacity to ferment over other apiculate yeasts. However, there are some differences between these two species that make them interesting from an enological point of view. H. vineae is well known for its ability to improve wine flavor. Genomic, transcriptomic, and metabolomic studies of H. vineae have enhanced our understanding of its utility within the wine industry. H. osmophila has been less characterized in wine production, although its capacity to increase pleasant aromas in red wines was reported recently. The objective of this study was to evaluate differences in wine fermentation performance between these two Hanseniaspora species. Single-strain microfermentations were carried out with Chardonnay grape must inoculated with H. vineae Hv205 and H. osmophila AWRI3579. In addition, H. uvarum AWRI1280, representing the Hanseniaspora fruit clade, and the industrial strain Saccharomyces cerevisiae ALG804 were used as controls for fermentation performance. Wine aromas were characterized chemically by gas chromatography-mass spectrometry and a descriptive sensory analysis was performed by an expert panel of tasters. Both species contributed positive aroma to final wines, while no defects were detected compared to H. uvarum. Wines fermented with H. vineae had significantly greater concentrations of 2-phenylethyl, tryptophol, tyrosol acetates, acetoin, and benzyl alcohol than H. osmophila wines. Sensory analysis showed increased intensity of fruity and flowery notes in wines fermented with H. vineae. Higher gene copy numbers of putative acetyl transferases found in H.vineae compared to H. osmophila might explain the increased capacity for acetate synthesis.

Funding Support: Agencia de Investigacion e Innovacion ANII, Proyecto ALI 2_2019_1_155314