Phenotypic characterisation of fermentation performance and genome sequence analysis in an ale yeast strain

Abstract

Saccharomyces cerevisiae is an essential fermentation ingredient in the brewing industry, where its genomic information and fermentation traits profoundly influence final product characteristics. Here, a comprehensive phenotypic and genomic characterisation of the ale yeast strain (CGMCC 2.0002) was performed under simulated brewing conditions. Microscopic observations revealed that the strain exhibits an ellipsoidal morphology with smooth cell surfaces. During brewing, fermentation at 20 °C resulted in accelerated sugar depletion and significantly higher alcohol production compared with fermentation at 11 °C, although its flocculation properties were weaker at the higher temperature. Sensory evaluation indicated that the beer produced at 20 °C exhibited improved colour and taste. Meanwhile, the concentrations of ethyl acetate, isoamyl acetate, catechin, and salicylic acid in the beer all increased. Whole-genome resequencing using the S. cerevisiae S288C reference genome identified 42 711 single nucleotide polymorphisms, 4 725 insertions and deletions, and 562 structural variations in ale yeast. Notably, 21 mutated loci were situated within the essential genes of the glycolytic pathway. These findings establish a solid genomic and physiological baseline for optimising the application of this strain in craft beer production.