Role Of non-Saccharomyces Yeasts Research Articles

The Role and Use of Non-Saccharomyces Yeasts in Wine Production

The contribution by the numerous grape-must-associated non-Saccharomyces yeasts to wine fermentation has been debated extensively. These yeasts, naturally present in all wine fermentations, are metabolically active and their metabolites can impact on wine quality. Although often seen as a source of microbial spoilage, there is substantial contrary evidence pointing to a positive contribution by these yeasts. The role of non-Saccharomyces yeasts in wine fermentation is therefore receiving increasing attention by wine microbiologists in Old and New World wine producing countries. Species that have been investigated for wine production thus far include those from the Candida, Kloeckera, Hanseniaspora, Zygosaccharomyces, Schizosaccharomyces, Torulaspora, Brettanomyces, Saccharomycodes, Pichia and Williopsis genera. In this review the use and role of non-Saccharomyces yeast in wine production is presented and research trends are discussed.

Role of non-Saccharomyces yeasts in Korean wines produced from Campbell Early grapes: Potential use of Hanseniaspora uvarum as a starter culture

Several yeasts were isolated from Campbell Early grapes (Vitis labrusca cultivar Campbell Early), the major grape cultivar in Korea, grown in two different regions. PCR-RFLP analysis of the ITS I-5.8S-ITS II region showed that 34 isolates out of a total of 40 were in the same group. Phylogenetic analysis revealed that the major strain belonged to one species, Hanseniaspora uvarum, although they displayed some nucleotide mismatches between them. During spontaneous alcohol fermentation at 20 °C, the two grape musts containing 24 °Brix sugar exhibited similar fermentation patterns with differences in final alcohol production and yeast viable counts. PCR analysis of the yeasts randomly isolated during the fermentation using an intron splice site primer showed changes in yeast flora between 8 and 10 days of fermentation. We found that the dominant yeasts displaying various PCR patterns using the primer remained the same throughout the early stages of fermentation, as determined by molecular typing of their ITS regions using PCR-RFLP, and these yeasts were identical to those isolated from grape berries. Among the isolates, the strain designated SS6 was selected based on its potassium metabisulfite resistance, alcohol production (distillation method), and flavor (by sniffing test) of grape juice. When Campbell Early grape must was inoculated with H. uvarum SS6 cells, no differences in fermentation pattern were observed compared with that inoculated with cells of Saccharomyces cerevisiae W-3, an industrial wine yeast strain. However, SS6 wine showed higher levels of organic acid (especially lactic acid), aldehydes, and minor alcohols (except n-propyl alcohol), as well as a higher score in sensory evaluation, compared to those of W-3 wine.

The Occurrence of Non-Saccharomyces cerevisiae Yeast Species Over Three Vintages in Four Vineyards and Grape Musts From Four Production Regions of the Western Cape, South Africa

The role of non-Saccharomyces yeasts in wine production has been extensively debated and there is growing evidence that non-Saccharomyces yeasts play an important role in wine quality. It has been suggested that metabolites formed by some non-Saccharomyces species may contribute to wine quality. Recently a comprehensive, longterm research programme was launched by role players in the South African wine industry, whose aims include the isolation, characterisation and preservation of the natural yeast biodiversity of the Western Cape. As part of the programme, this paper investigates the presence of non-Saccharomyces yeast species over three vintages in four vineyards and musts in four distinct areas of the Western Cape. Samples were taken and the non-Saccharomyces yeast isolates were characterised by biochemical profiling and pulse field gel electrophoresis. In total 720 yeasts representing 24 species were isolated. Predominant species found in the must samples, i.e. Candida stellata, Kloeckera apiculata, Candida pulcherrima and Candida colliculosa, should have the most impact on subsequent fermentation.