On the 30th of August, Associate Professor Valdimir Jirank gave this talk as part of the WIC Seminar Series. You can listen to the talk here or you can watch the slidecast below.
The microbiology of the winemaking process, which includes inoculated strains of the yeast Saccharomyces cerevisiae and the lactic acid bacterium, Oenococcus oeni, is critical to process efficiency and wine quality. In each case these organisms are required to complete a core conversion (sugar to ethanol or lactate to malate, respectively) as well as make desirable sensory contributions. These activities typically occur under extreme conditions which may include high sugar (osmolarity) and ethanol content and low pH, temperature and nutrient availability.
We have used mutant screening strategies and functional genomic approaches to identify the basis of superior yeast performance in the face of these challenges. In addition we have use adaptive evolution to yield yeast with enhance fermentation reliability based on increase nitrogen efficiency, fructophilicity or general robustness. In parallel work, we have isolated and heterologously expressed genes from O. oeni which encode esterases or glucosidases. Characterisation of these gene products has provided insights into their roles within the cell as well as potential contribution to wine.