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Gewählte Master / Diploma Thesis:

Christoph Reiterich (2017): Molecular investigation of lactic acid bacteria in wine.
Master / Diploma Thesis - Institut für Lebensmittelwissenschaften, BOKU-Universität für Bodenkultur, pp 245. UB BOKU obvsg

Data Source: ZID Abstracts
Lactic acid bacteria (LAB) play a crucial role in the process of winemaking. Next to yeasts, which are responsible for alcoholic fermentation, they are the main effectors of malolactic fermentation (MLF) which is particularly of importance in red wine. However, they can also cause wine spoilage. The aim of this work was the investigation of the LAB diversity in wine samples using PCR-DGGE method which has proven to be a quick and reliable tool to study the LAB community and their fluctuation over the time of vinification. The primer sets rpoB, WLAB, Lac and WBAC have been tested as a prosecution of a previous study performed by Filipp (2011). Furthermore different isolates were tested for the production of ethyl carbamate, exopolysaccharides (EPS) and β-glucosidase. For the detection of LAB in wine in terms of specificity and sensitivity, the WLAB system was found to be the most suitable one. The rpoB system also performed well but showed a high limit of detection. The Lac and WBAC system were not appropriate due to multiple bands complicating the evaluation. Based on the obtained results, it can be concluded that PCR-DGGE is an effective and promising procedure to analyze and monitor LAB in wine but further research has to be made in order to improve the results. The results regarding oenological properties showed a high potential for the formation of ethyl carbamate in all tested species, including O. oeni. The investigation of the ability to form EPS confirmed Pd. damnosus as the main producer of EPS but also positive isolates of O. oeni were found. Only 16 of 259 isolates were tested positive for the presence of the β-glycosidase gene. These isolates belonged to the species Lb. brevis, Lb. paracasei, Lb. plantarum, Pd. parvulus and O. oeni. Further studies such as microvinification tests are required to check appropriate isolates prior to their usage.

Beurteilende(r): Kneifel Wolfgang
1.Mitwirkender: Domig Konrad
2.Mitwirkender: Mayrhofer Sigrid

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