On the origins and industrial applications of Saccharomyces cerevisiae × Saccharomyces kudriavzevii hybrids

Companies based on alcoholic fermentation products, such as wine, beer and biofuels, use yeasts to make their products. Each industrial process utilizes different media conditions, which differ in sugar content, the presence of inhibitors and fermentation temperature. Saccharomyces cerevisiae has traditionally been the main yeast responsible for most fermentation processes. However, the market is changing due to consumer demand and external factors such as climate change. Some processes, such as biofuel production or winemaking, require new yeasts to solve specific challenges, especially those associated with sustainability, novel flavours and altered alcohol content. One of the proposed solutions is the application of yeast hybrids. The lager beer market has been dominated by S. cerevisiae × S. eubayanus hybrids. However, several less thoroughly studied hybrids have been isolated from other diverse industrial processes. Here we focus on S. cerevisiae × S. kudriavzevii hybrids, which have been isolated from diverse industrial conditions that include wine, ale beer, cider and dietary supplements. Emerging data suggest an extended and complex story of adaptation of these hybrids to traditional industrial conditions. S. cerevisiae × S. kudriavzevii hybrids are also being explored for new industrial applications, such as biofuels. This review describes the past, present and future of S. cerevisiae × S. kudriavzevii hybrids.DP is a Marie Sklodowska-Curie fellow of the European Union's Horizon 2020 research and innovation programme, grant agreement No. 747775. DP and CTH: this material is based upon work supported by the National Science Foundation under Grant No. DEB-1253634, the Robert Draper Technology Innovation Fund from the Wisconsin Alumni Research Foundation, and funded in part by the DOE Great Lakes Bioenergy Research Center (DOE Office of Science BER DE-FC02-07ER64494). CTH is supported by the USDA National Institute of Food and Agriculture (Hatch Project 1003258). CTH is a Pew Scholar in the Biomedical Sciences, supported by the Pew Charitable Trusts. AQ and EB acknowledge Generalitat Valenciana grant PROMETEOII/2014/042 and Spanish Government (MINECO) and European Union FEDER grants AGL2015-67504-C3-01R (to AQ) and AGL2015-67504-C3-03-R (to EB). RPT is supported by the aforementioned grants associated to AQ.Peer reviewe