Metagenomics in wine fermentation

Wine is influenced by a diverse and complex community of microorganisms. During the alcoholic fermentation these microorganisms are influencing the aroma and flavour of wine. This PhD thesis focuses on studying this microbial community during wine fermentation with the use of metagenomics. In general, metagenomics is the study of genetic material recovered directly from environmental samples.
The decreasing costs in sequencing, the process of determining the sequence of an organism's genome, make it possible to use metagenomics to characterise the microbial communities in various environments. Here, we applied it to characterize the microorganisms present in wine fermentation.
The decrease in sequencing costs also leads to an increasing number of sequencing projects. To help non-bioinformatics users to analyse their data, we developed a tool to visualise and analyse metagenomics data.
Today, most wines are produced by inoculating grape must with yeast or bacteria. This is mainly to avoid stuck fermentations. However, this also reduces the complexity of the microbial community which is believed to result in less complex wines compared to naturally occurring spontaneous fermentations. Here, we investigate the microorganisms present in spontaneous fermentations which originate from the vineyards. We show that even when the grapes come from the same grape variety and the same region, there are still differences in the abundance of microorganisms during the alcoholic fermentation. This shows that the vineyard affects the microbial community present during fermentation and with this the resulting wine.
In general, the wine industry will benefit from the knowledge gained about the microbial community present during wine fermentation, i.e. in spontaneous fermentation. Further, companies producing inoculants will be interested as spontaneous fermentations are believed to result in more complex wines.