S. pastorianus, an S. cerevisiae × S. eubayanus hybrid, is used for production of lager beer, the most produced alcoholic beverage worldwide. It emerged by spontaneous hybridization and colonized early lager brewing processes. Despite accumulation and analysis of genome sequencing data of S. pastorianus parental genomes, the genetic blueprint of industrially relevant phenotypes remains unresolved. Assimilation of maltotriose, an abundant sugar in wort, has been postulated to be inherited from the S. cerevisiae parent. Here, we demonstrate that although Asian S. eubayanus isolates harbor a functional maltotriose transporter SeAGT1 gene, they are unable to grow on α-oligoglucosides, but expression of S. cerevisiae regulator MAL13 (ScMAL13) was sufficient to restore growth on trisaccharides. We hypothesized that the S. pastorianus maltotriose phenotype results from regulatory interaction between S. cerevisiae maltose transcription activator and the promoter of SeAGT1. We experimentally confirmed the heterotic nature of the phenotype, and thus these results provide experimental evidence of the evolutionary origin of an essential phenotype of lager brewing strains.

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Standardization can be achieved in multiple ways; firms may join forces and develop standards in standardization committees, they may compete directly on the market in standards battles, or governmental agencies may impose standards. This paper studies criteria for the selection of standards in a situation in which these three forms of standardization occur simultaneously (multi-mode standardization). The paper attempts to arrive at weights for these criteria by applying them to the case of phosphorus recovery from municipal waste water, a technological process that fits the transition to a circular economy but that is still lacking standardization. A contribution is made to the standardization literature by empirically studying the case of multi-mode standardization and by applying standard success criteria to the area of water treatment.