Integrative genomics reveals Pichia kluyveri's potential for enhanced flavor compounds production during alcoholic fermentation

Abstract

Aroma formation during alcoholic fermentation is largely driven by yeast metabolism. Non-Saccharomyces strains have attracted increasing attention for their ability to enhance flavor diversity and sensory complexity. In this study, three non-Saccharomyces strains—Hanseniaspora uvarum QTX22, Metschnikowia pulcherrima YC-15, and Pichia kluyveri QTX15—were isolated from Marselan wine. Whole-genome sequencing and comparative genomic analyses revealed that P. kluyveri QTX15 exhibited moderate gene family expansion, with significant enrichment in redox-related pathways, suggesting enhanced metabolic potential. Notably, gene families associated with redox processes and ester biosynthesis were prominently represented, indicating potential for elevated aroma compound production. To experimentally validate these genomic insights, fermentation trials were performed using Marselan grape must that was sterilized at 121 °C to ensure microbiological control. While this standardized condition guarantees reproducibility, it should be noted that such intense heat may alter must composition compared to typical winemaking practice. Fermentations with P. kluyveri QTX15 and S. cerevisiae RC212 were conducted under static conditions at 28 °C. Gas chromatography–mass spectrometry (GC-MS), combined with multivariate statistical analysis including variable importance in projection (VIP) scores and sensory thresholds, highlighted 15 aroma compounds that may contribute to the wine's aroma profile. Compared with S. cerevisiae RC212, P. kluyveri QTX15 produced higher levels of acetate esters such as phenylethyl acetate (9190 μg/L vs. 1580 μg/L), isobutyl acetate, and isoamyl acetate —showing 2- to 6-fold increases—contributing to intensified fruity and floral aromas. These findings identify P. kluyveri QTX15 as a valuable non-Saccharomyces resource for enhancing aroma quality in fermented beverages, supporting its application in food and beverage fermentation.