Assessing the Oenological Potential of Nakazawaea ishiwadae, Candida railenensis and Debaryomyces hansenii Strains in Mixed-Culture Grape Must Fermentation with Saccharomyces cerevisiae

Niel Van Wyk,Isak S Pretorius,Christian Von Wallbrunn

doi:10.3390/fermentation6020049

Abstract

Recently, there has been a growing interest in the role of non-Saccharomyces yeast (NSY) as a coculturing partner with Saccharomyces cerevisiae during grape must fermentation. We investigated three new strains, namely Nakazawaea ishiwadae, Candida railenensis and Debaryomyces hansenii, for their oenological potential in mixed-culture micro-vinifications with S. cerevisiae Vin13 using Muscaris grape must. None of the NSY strains impeded the fermentation performance as all the mixed-culture experiments finished at the same time. Coculturing with N. ishiwadae yielded significantly higher concentrations of ethyl and acetate esters in the final wine product. Apart from higher acetic acid levels, wines produced with C. railenensis and D. hansenii yielded much lower esters concentrations. The concentrations of certain terpenes and norisoprenoids were also significantly modulated in the mixed-culture fermentations. This study reveals the rarely reported species of N. ishiwadae as a promising coculturing partner for increasing aroma-active compounds in a wine.

Highlights

Since the second half of the 1960s, commercial starter cultures of Saccharomyces cerevisiae wine yeast strains became available and soon afterwards were widely adopted among the winemaking community.Using starter cultures allowed for a far more reliable fermentation with far fewer reports of stuck or sluggish fermentations [1]
We explored the utility of three non-Saccharomyces yeasts (NSY) yeasts with limited knowledge about their co-fermenting contributions—Nakazawaea ishiwadae, Candida railenensis and Debaryomyces hansenii—in mixed-culture Muscaris grape must fermentations
Based on their 5.8S-ITS region two of the six strains that were identified as Debaryomyces hansenii, two as Metschnikowia pulcherrima, one as Candida railenensis and one as Nakazawaea ishiwadae (Figure 1)

Summary

Introduction

Since the second half of the 1960s, commercial starter cultures of Saccharomyces cerevisiae wine yeast strains became available and soon afterwards were widely adopted among the winemaking community.Using starter cultures allowed for a far more reliable fermentation with far fewer reports of stuck or sluggish fermentations [1]. Since the second half of the 1960s, commercial starter cultures of Saccharomyces cerevisiae wine yeast strains became available and soon afterwards were widely adopted among the winemaking community. Would be necessary in order to expand on the winemaking capabilities of wine yeast, including to develop on the breath of possible flavor profiles for wines prepared using defined cultures. Wine yeast researchers have, for the past twenty years, started to investigate the use of non-Saccharomyces yeasts (NSY; called non-conventional yeasts) as starter culture co-partners with S. cerevisiae. Several of these investigations resulted in the successful coculturing of Saccharomyces and non-Saccharomyces and yielded wines with improved qualities. Examples of improved characteristics included a marked decrease in ethanol levels, increased release of varietal

Methods

Results

Conclusion