Macrowine 2021
IVES 9 IVES Conference Series 9 Characterization of non-Saccharomyces yeast and its interaction with Saccharomyces cerevisiae with investigation of fermentation kinetics and aromatic composition

Characterization of non-Saccharomyces yeast and its interaction with Saccharomyces cerevisiae with investigation of fermentation kinetics and aromatic composition


There is growing evidence that non-Saccharomyces yeasts can be utilized to enhance wine aroma although little research has been done on most non-Saccharomyces species. This study was designed to genetically and phenotypically characterize two local South African non-Saccharomyces species, Kazachstania aerobia and Wickerhamomyces anomalus, in addition to determining their fermentation potential and volatile profiles in synthetic grape must. Genetic differences between isolates were investigated using the RAPD method and phenotypic heterogeneity was determined using plate spotting. Isolates were assessed for heat, alcohol, saline, osmotic and oxidative stress tolerance for phenotypic strain characterization. Eight K. aerobia and thirteen W. anomalus isolates were used to ferment synthetic grape must. After characterization three K. aerobia strains and two W. anomalus strains were then selected for the co-culture fermentations with S. cerevisiae VIN13 and EC1118. Fermentations were done by inoculating yeast simultaneously as well as sequentially, 48 hours apart. Single culture fermentations were used as controls. Aroma compounds in the synthetic wine were quantified using GC-FID. RAPD analysis classified W. anomalus isolates into four distinct strains in accordance to place of origin. Phenotypic variations were also evident in the proposed strains’ resistance to oxidative, saline and osmotic stresses compared to VIN13. Interestingly, there were phenotypic differences observed within the same strain groupings. The K. aerobia isolates showed no marked genetic differences, but with slight variations in stress response. Overall, the CBS strain had a higher growth performance than the other strains with K. aerobia Y965 showing the least growth. In co-inoculation experiments of VIN13 and K. aerobia, the latter persisted until day 9 when VIN13 was introduced on day 2 and until day 7 when VIN13 was introduced on day 0 regardless of isolate’s phenotype. When fermenting with EC1118, W. anomalus had higher cell densities compared to when fermented with VIN13. In sequential fermentations W. anomalus survived until day 9 (when fermenting with strain Y934-C) and day 7 (when fermenting with strain LO632). When inoculating simultaneously with both strains of S. cerevisiae, W. anomalus was detected in the must until day five. Kazachstania aerobia and W. anomalus gives a unique aroma profile to wines. Although as single cultures these yeast do not ferment wines to dryness, they are capable of conferring favourable wine aroma when in association S. cerevisiae strains with no risk of sluggish fermentation. Inoculating S. cerevisiae sequentially to the non-Saccharomyces yeast allows sufficient time for the non-Saccharomyces to impart valuable aroma compounds. This study provides a basis for further work on wine quality improvement through exploitation of non-Saccharomyces yeasts.

Publication date: May 17, 2024

Issue: Macrowine 2016

Type: Poster


Judy Lombard*, Florian Bauer, Hannibal Musarurwa, Sandra du Toit


Contact the author


IVES Conference Series | Macrowine | Macrowine 2016


Related articles…

A combination of biotechnology tools and coopers elements for an alternative the addition of SO2 at the end of the malolactic fermentation in red wines or at the “mutage” for the “liquoreux” wines

In red wines the post-MLF SO2 addition is an essential event. It is also the case for the “mutage” during the elaboration of the “liquoreux”. At these moments SO2 plays an antimicrobial action and an antioxidant effect. But at current pH of wines, ensuring a powerful molecular SO2 has become very difficult. Recent work on Brettanomyces strains have also shown that some strains are resistant up to 1.2 mg / L of molecular SO2. It’s also the case of the some Saccharomuces or Zygosaccharomyces strains suitable to re-ferment “liquoreux” wines after the “mutage”.

New biological tools to control and secure malolactic fermentation in high pH wines

Originally, the role of the malolactic fermentation (MLF) was simply to improve the microbial stability of wine via biological deacidification. However, there is an accumulation of evidence to support the fact that lactic acid bacteria (LAB) also contribute positively to the taste and aroma of wine. Many different LAB enter into grape juice and wine from the surface of grape berries, cluster stems, vine leaves, soil and winery equipment. Due to the highly selective environment of juices and wine, only a few types of LAB are able to grow.

Microbial life in the grapevine: what can we expect from the leaf microbiome?

The above-ground parts of plants, which constitute the phyllosphere, have long been considered devoid of bacteria and fungi, at least in their internal tissues and microbial presence there was long considered a sign of disease. However, recent studies have shown that plants harbour complex bacterial communities, the so-called “microbiome”[1]. We are only beginning to unravel the origin of these bacterial plant inhabitants, their community structure and their roles, which in analogy to the gut microbiome, are likely to be of essential nature. Among their multifaceted metabolic possibilities, bacteria have been recently demonstrated to emit a wide range of volatile organic compounds (VOCs), which can greatly impact the growth and development of both the plant and its disease-causing agents.

Analysis of off flavours in grapes infected with the fungal bunch rot pathogens, Aspergillus, Botrytis and Pencillium

Fungal bunch rots of grapes cause major losses to grape yield worldwide, yet the impact these moulds have on grape and wine quality is not well characterised. We sought to investigate the formation of unwanted volatile compounds of fungal origin in both synthetic grape juice culture media and in inoculated grape berries. Botrytis cinerea, Aspergillus niger, Aspergillus carbonarius, or Pencillium expansum were grown in synthetic grape juice medium and the culture homogenates analysed 4 and 7 days post inoculation. HS-SPME-GC-MS analysis of the culture homogenates 4 days post inoculation demonstrated that each of the fungi examined produced varying quantities of the mushroom or fungus-like aroma compounds, 1-Octen-3-ol, 1-Octen-3-one and 3-Octanone with A. carbonarius producing up to ten times the amounts of all three metabolites per mg of dry mycelium.

Colour assessment of port wines using colorimetric and spectrophotometric methods

Colour is an important quality parameter in wines and is the result of a complex mixture of pigments
(including anthocyanins and their derivatives, quinones, xanthyllium compounds, etc.). Red wine colour changes over time as pigments react between themselves and with other wine macromolecules
(particularly polyphenols). During wine tasting, colour is normally assessed on the outer rim of the wine profile in a tilted glass, since most wines are too opaque to be analysed in the middle of the glass. Therefore, depending on the depth of observation considered, the perception of wine colour can be different.