The brewing industry is constantly searching for unconventional yeast species to produce new beverages with unique flavours and aromas. Yeasts of the genus Hanseniaspora, which produce interesting aromatic compounds, represent a great potential. Screening tests are often applied to select a new brewing yeast. These consist of different culture media in microtiter format on which the growth of the yeasts is determined. To characterize yeasts of the genus Hanseniaspora, brewing-specific properties were tested on 45 strains, most of which were isolated from forest environments in Germany, with the remainder selected from the Collection of Industrial Microorganisms (ZIM). All yeasts were identified by sequencing ITS or D1/D2 regions of ribosomal gene prior to testing. The assays were used to determine an ability to assimilate maltose, resistance to ethanol, iso-α-acids, and to a combination of ethanol and iso-α-acids, enzymatic activity of β-lyases, diastatic activity (starch) and ability to degrade ferulic acid to volatile phenols. Screening results varied between strains. Of all strains tested, 15 were further selected for fermentation trials, at the end of which the aromatic profiles of beers were determined. These results were compared with the screening results and we found that the screening tests could not predict flavours produced. For the production of flavoured beer, we wanted to use species of Hanseniaspora jakobsenii, which, according to the literature, can grow poorly on maltose. With the aim to improve this trait we used adaptive laboratory evolution, but were unsuccessful in improving the trait. We also performed electrophoretic karyotyping by pulsed-field gel electrophoresis and tested an ability to sporulate. We found that H. jakobsenii has 8 chromosomes and is able to sporulate.
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