Lachancea fermentati strains isolated from Kombucha: fundamental insights, and practical application in low alcohol beer brewing

dc.contributor.authorBellut, Konstantin
dc.contributor.authorKrogerus, Kristoffer
dc.contributor.authorArendt, Elke K.
dc.contributor.funderFonds Baillet Latouren
dc.description.abstractWith a growing interest in non-alcoholic and low alcohol beer (NABLAB), researchers are looking into non-conventional yeasts to harness their special metabolic traits for their production. One of the investigated species is Lachancea fermentati, which possesses the uncommon ability to produce significant amounts of lactic acid during alcoholic fermentation, resulting in the accumulation of lactic acid while exhibiting reduced ethanol production. In this study, four Lachancea fermentati strains isolated from individual kombucha cultures were investigated. Whole genome sequencing was performed, and the strains were characterized for important brewing characteristics (e.g., sugar utilization) and sensitivities toward stress factors. A screening in wort extract was performed to elucidate strain-dependent differences, followed by fermentation optimization to enhance lactic acid production. Finally, a low alcohol beer was produced at 60 L pilot-scale. The genomes of the kombucha isolates were diverse and could be separated into two phylogenetic groups, which were related to their geographical origin. Compared to a Saccharomyces cerevisiae brewersâ yeast, the strainsâ sensitivities to alcohol and acidic conditions were low, while their sensitivities toward osmotic stress were higher. In the screening, lactic acid production showed significant, strain-dependent differences. Fermentation optimization by means of response surface methodology (RSM) revealed an increased lactic acid production at a low pitching rate, high fermentation temperature, and high extract content. It was shown that a high initial glucose concentration led to the highest lactic acid production (max. 18.0 mM). The data indicated that simultaneous lactic acid production and ethanol production occurred as long as glucose was present. When glucose was depleted and/or lactic acid concentrations were high, the production shifted toward the ethanol pathway as the sole pathway. A low alcohol beer (<1.3% ABV) was produced at 60 L pilot-scale by means of stopped fermentation. The beer exhibited a balanced ratio of sweetness from residual sugars and acidity from the lactic acid produced (13.6 mM). However, due to the stopped fermentation, high levels of diacetyl were present, which could necessitate further process intervention to reduce concentrations to acceptable levels.en
dc.description.statusPeer revieweden
dc.description.versionPublished Versionen
dc.identifier.citationBellut, K., Krogerus K. and Arendt E. K. (2020) 'Lachancea fermentati Strains Isolated From Kombucha: Fundamental Insights, and Practical Application in Low Alcohol Beer Brewing', Frontiers In Microbiology, 11, (21 pp). doi: 10.3389/fmicb.2020.00764en
dc.identifier.journaltitleFrontiers In Microbiologyen
dc.publisherFrontiers Mediaen
dc.rights© 2020 Bellut, Krogerus and Arendt. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.en
dc.subjectLachancea fermentatien
dc.subjectLactic aciden
dc.subjectResponse surface methodologyen
dc.subjectWhole genome sequencingen
dc.titleLachancea fermentati strains isolated from Kombucha: fundamental insights, and practical application in low alcohol beer brewingen
dc.typeArticle (peer-reviewed)en
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