Co-inoculation with Saccharomyces cerevisiae and non-Saccharomyces yeasts is an effective method to improve the flavor of cider. Wickerhamomyces anomalus, known for its high ester production capacity, was evaluated in combination with S. cerevisiae to identify optimal mixed yeast inoculants for improved sensory characteristics. Three W. anomalus strains and three inoculation ratio attributes (1:5, 1:1, and 5:1) were tested to assess their impact on the physicochemical indices and sensory attributes of cider. All the strains used as starters developed fermentation-producing ciders with alcoholic degrees between 6.22 and 6.36 (% v/v). Co-inoculation with W. anomalus resulted in significantly higher ester, volatile acid, and higher alcohol levels compared to those of S. cerevisiae monocultures, increasing the complexity of fruity and floral aromas. Furthermore, the proportion of W. anomalus strains in the inoculations was positively correlated with increased aromatic esters and higher alcohols. The Sc–Wa (1:5) cider showed the highest contents of ethyl ethanoate and 3-methylbutan-1-ol, contributing to a nail polish-like aroma. Sc–Wa (1:1) yielded a higher aromatic diversity than did Sc–Wa (5:1), suggesting that co-inoculation with a ratio of 1:1 may provide an effective fermentation strategy for cider aroma enhancement. These findings offer valuable insights into how non-Saccharomyces yeasts can be effectively applied in cider co-fermentation, providing a foundation for their future use in industrial applications.

Non-Saccharomyces yeasts have the potential to ameliorate wine ethanol levels, but such fit-for-purpose yeast strains are still lacking. Seventy-one indigenous non-Saccharomyces yeasts isolated from spontaneous fermentations of four wine regions in China (Ningxia, Xinjiang, Gansu, and Shaanxi) were screened for ethanol formation and were characterized for major metabolite profiles in synthetic grape juice fermentation to obtain non-Saccharomyces yeasts with low ethanol yields. Four Hanseniaspora strains with less volatile acidity production were primarily selected, and their ethanol yield was reduced by 22–32% compared to S. cerevisiae. These strains were further evaluated for oenological properties, namely ethanol and temperature tolerance, H₂S production, and killer activities against S. cerevisiae. Strain HuC-3-2 was then subjected to Atmospheric Room Temperature Plasma (ARTP) mutagenesis, and a mutant (HuC32-2-72) with rapid growth and optimized ethanol-reducing capability was obtained. The best-performing strains were further characterized in sequential fermentations with S. cerevisiae in Merlot juice, and resulted in a 1.4% v/v decrease in ethanol yield. Comprehensive analysis of yeast populations and the production of key metabolites highlighted important carbon sinks, as well as glycerol formation, partially accounting for the ethanol reduction. In addition to ethanol amelioration, the Hanseniaspora strains also led to alterations in many metabolites, including volatile compounds and some organic acids, which can further modulate wine aroma and flavor.

Hanseniaspora uvarum is a representative non- Saccharomyces species that plays a significant role in fermentation processes such as winemaking. In recent years, this species has gained attention in food engineering and evolutionary biology. However, the population genomic signatures in this species remain poorly understood. In this study, a population genomics analysis was conducted on 151 H. uvarum strains (45 from Ningxia, China; 21 from other regions of China; 67 from Australia; and 18 from other regions or of unspecified origin), and a pangenome analysis was performed on 159 strains, incorporating eight additional genome assemblies. Phylogenetic analysis, ancestry coefficient analysis, and principal component analysis generally distinguished Chinese strains from those sampled on other continents. However, substantial post-divergence gene flow and introgression were inferred between intercontinentally paired clades. Positively selected candidate genes exhibited region-specific patterns: GO terms related to the positive regulation of filamentous growth in response to external stimuli were significantly enriched in the Ningxia strains; the stress-related GO term “cytoplasmic stress granule” was significantly enriched in both the Ningxia and Australian strains, but with distinct sets of associated genes. Although the samples were primarily isolated from anthropogenic environments, H. uvarum exhibited an open pangenome, indicating substantial adaptive potential to diverse stresses. This study advances our understanding of the evolutionary dynamics of H. uvarum and establishes a genomic foundation for future ecological and industrial research on this yeast.