Fermentation processes in beer brewing are based on the use of yeast strains from the Saccharomyces genus. Such starter cultures enable consistent and efficient production of beer but limited microbial diversity in the starter cultures reduces the sensory profile and complexity of the final products. Aroma improvement and an increase in flavor diversity can be achieved by bioaromatization of beer, which involves use of non-Saccharomyces yeasts for aroma production. The yeast Hanseniaspora jakobsenii has the potential for bioaromatization, but it grows only weakly on wort. Therefore, the aim of the master's thesis was to improve the uptake of maltose by the yeast H. jakobsenii ZIM 2603 with adaptive laboratory evolution (ALE). ALE was carried out for 42 days in a microtiter plate in a medium with maltose and growth was monitored by measuring the absorbance in real time. To set up the ALE experiment, we first determined the growth parameters of the yeast H. jakobsenii in media with glucose and maltose as different carbon sources in presence or absence of oxygen. We determined the growth curve of the strain H. jakobsenii using absorbance measurements and calculated maximum specific growth rate and generation time. Our results show that the yeast H. jakobsenii reached the highest maximum specific growth rate in an aerobic environment in the rich YPD medium, while it achieved the lowest maximum specific growth rate in the YP medium containing 20% glucose under anaerobic conditions. Growth in maltose medium was very weak and did not improve even after ALE. The results show that maltose uptake did not improve and that there were no mutations in the MALx3 gene of the evolved clones of the populations.
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