Sorting Lachancea from Saccharomyces: investigating viability and growth of resuspended Lachancea thermotolerans sorted via flow cytometry after exposure of Saccharomyces cerevisiae in a mixed fermentation

Institut for Fødevarevidenskab 2018

Mixed fermentations of Lachancea thermotolerans with saccharomyces cerevisiae show an inhibited viability and growth of L. thermotolerans. This is both due to harmful compounds excreted by S. cerevisiae as well as damaging cell-to-cell contact. Growth of L. thermotolerans and S. cerevisiae in mixed and single fermentations are investigated. The fermentations were carried out in synthetic grape must and the growth was determined on Wallerstein Laboratory Nutritional agar. After this L. thermotolerans cells are sorted from the mixed fermentation by means of flow cytometry at day 1 and 3. These sorted cells are then resuspended with S. cerevisiae to examine the growth in a secondary fermentation. The method for sorting the L. thermotolerans was developed throughout the study. Mixed fermentations showed that the growth of L. thermotolerans was inhibited in the presence of S. cerevisiae. The combination of the yeast did not have any effect on S. cerevisiae. After a workable sorting method was developed, L. thermotolerans was sorted from the mixed fermentation at day 1 and 3. The yeast sorted at day 1 died out after 3 days of re-fermentation with fresh S. cerevisiae whereas the yeast sorted at day 3 showed much better survivability. L. thermotolerans sorted after 3 days of fermentation survived throughout the 6 days of growth examination done in this study and showed a very slight rise in concentration during the period. These results demonstrate that an adaptation or an innate characteristic of the L. thermotolerans cells give them the ability to better survive in the presence of S. cerevisiae and opens up for interesting work in what these characteristics might be.

Flow cytometry; Lachancea; Saccharomyces; MASTERTHESIS

Open access content. Open access content

57 pages
application/pdf
English

DAV oai:pure.atira.dk:studentproject/1b01515e-b35f-40db-934d-1c955b11d782
1035523145

UNIV OF COPENHAGEN
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