Effects of High Sugar Content on Fermentation Dynamics and Some Metabolites of Wine-Related Yeast Species Saccharomyces cerevisiae, S. uvarum and Starmerella bacillaris
Szent István University Faculty of Horticultural Science Department of Oenology, Ménesi út 45, 1118 Budapest, Hungary
Received: 25 July 2019
Accepted: 18 February 2020
Starmerella bacillaris, Candida zemplinina, non-Saccharomyces yeast, high sugar concentration, metabolic footprint
Starmerella bacillaris (synonym Candida zemplinina) is an important non-Saccharomycesyeast in winemaking with valuable oenological properties, accompanying Saccharomycesspecies in sweet wine fermentation, and has also been suggested for application ascombined starter culture in dry or sweet wines. In this study, the major metabolites andnitrogen utilization of these yeasts are evaluated in the musts with high or extremely highsugar concentration. The change in the metabolic footprint of Saccharomyces cerevisiae,Saccharomyces uvarum and Starmerella bacillaris strains was compared when they werepresent as pure cultures in chemically defined grape juice medium with 220 and 320 g/L ofsugar, to represent a fully matured and an overripe grape. Surprisingly, the extreme sugarconcentration did not result in a considerable change in the rate of sugar consumption;only a shift of the sugar consumption curves could be noticed for all species, especiallyfor Starmerella bacillaris. At the extreme sugar concentration, Starmerella bacillaris showedexcellent glycerol production, moderate nitrogen demand together with a noticeableproline utilisation. The change in the overall metabolite pattern of Starmerella bacillarisallowed clear discrimination from the change of the Saccharomyces species. In this experiment,the adequacy of this non-Saccharomyces yeast for co-fermentation in juices withhigh sugar concentration is highlighted. Moreover, the results suggest that Starmerellabacillaris has a more active adaptation mechanism to extremely high sugar concentration.