Impact of co-inoculation of Saccharomyces cerevisiae, Hanseniaspora uvarum and Oenococcus oeni autochthonous strains in controlled multi starter grape must fermentations

The use of multi-species starter cultures is an approach of increasing significance for winemakers in order to improve the general quality and safety of the final product. As first step of the present study, we isolated and characterize two Saccharomyces cerevisiae yeast starter strains, denoted as ITEM 167292 and ITEM 17293, from natural must fermentations of "Negroamaro" grapes. As second step, we studied the interactions during grape must fermentation between these two strains, the Hanseniaspora uvarum strain ITEM 8785 and five autochthonous Oenococcus oeni strains, by microbial counts and by quantifying L-malic acid and ethanol concentrations. The best performing O. oeni strain, namely OT4, was used to create, with the H. uvarum strain ITEM 8785, two mixed starter formulations with the strains ITEM 167292 and ITEM 17293. The three microbial species showed to be compatible and to complete the fermentative processes producing wines denoted by reduced acetic acid concentrations. The performance of the mixed starter formulations were then validated by carrying pilot-scale vinifications. At the best of our knowledge, this report is the first study regarding the utilization of selected H. uvarum/S. cerevisiae/O. oeni autochthonous strains in a simultaneous multi-starter inoculation for the industrial production of regional typical wines.