This study evaluated the oenological potential of two non-Saccharomyces yeast strains, Hanseniaspora opuntiae TR-5 and Zygosaccharomyces bailii L-25, isolated from extreme winemaking environments in southern Spain. Out of 156 yeast isolates screened from high-sugar musts and flor yeast biofilms, strains were selected based on their β-glucosidase activity, killer phenotype, and ethanol production, traits associated with aroma release and microbial competition. Fermentation trials on sugar-rich synthetic medium showed that both H. opuntiae and Z. bailii achieved ethanol yields of 10% v/v and residual sugars at 4 g/L. Co-culture and sequential inoculation, with H. opuntiae introduced first and Z. bailii added on day four, resulted in complete alcoholic fermentation and a reduction in undesirable acetoin levels compared to single-strain fermentations. These findings highlight the practical potential of using selected non-Saccharomyces strains in sequential fermentations to improve aroma complexity, fermentation reliability, and sensory quality in wines, even in the absence of Saccharomyces cerevisiae. The application of these strains offers a novel approach for precision oenology and varietal expression in challenging musts.

Non-Saccharomyces yeasts play a significant role in winemaking, offering unique benefits and contributing to wine complexity and varied and desirable aromatic profiles. This work focuses on the sensory improvement of Pedro Ximénez white wines using selected strains of Wickerhamomyces anomalus isolated from biologically aged wines. Chemical and microbiological analyses confirmed the implantation of W. anomalus; these yeast strains appear to displace indigenous non-Saccharomyces species in the must and produce large amounts of ethyl acetate and lower ethanol content. Wines made with W. anomalus strains were judged negatively by the tasting panel due to a nail polish/varnish odor and a strong, bitter taste; however, when these wines were blended with wine normally produced by spontaneous fermentation, the judges rated them positively, highlighting fruity aromas not detected under other conditions. These results conclude that W. anomalus strains isolated from biologically aged wines could be useful for modulating the sensory profile of white wines. Moreover, their use in combination with other yeasts or in immobilized form could improve the results obtained and avoid the blending process. The high yield of ethyl acetate produced by these strains could be of interest as an alternative to current methods of producing this compound, including the use of these wines for the production of quality vinegar.

The Criaderas and Solera system represents one of the most sophisticated aging methodologies in winemaking, producing distinctive Sherry wines through dynamic blending and biological aging processes. This traditional Spanish system, combined with the unique metabolic activities of flor yeast (Saccharomyces cerevisiae), creates wines of exceptional complexity and consistency. This comprehensive review synthesizes current literature on the Criaderas and Solera system, focusing on biological aging mechanisms, flor yeast dynamics, industrial applications, and contemporary challenges. Recent advances in genomic, proteomic and metabolomic studies of flor yeasts have been analyzed, alongside modern analytical approaches to the characterization of Sherry wine. The Criaderas and Solera system enables consistent wine quality through fractional blending across multiple aging levels. Flor yeasts exhibit specialized metabolic adaptations, including enhanced ethanol oxidation capacity, biofilm formation abilities, and stress resistance mechanisms. Modern applications extend beyond traditional winemaking to include biotechnological uses, immobilization techniques, and sustainable production methods. Current challenges include climate change impacts, maintaining genetic diversity, adapting to new technologies and meeting evolving consumer preferences. The integration of traditional knowledge with modern biotechnology offers promising opportunities for optimizing Sherry production. Understanding flor yeast ecology and metabolic pathways provides insights for developing innovative applications while preserving the authenticity of this centuries-old winemaking tradition.

Spanish “Fino”-style white wines are traditionally aged by a dynamic process under a flor veil of Saccharomyces cerevisiae, requiring ≥15% (v/v) ethanol, which is typically achieved through fortification. Market demand for lower-alcohol wines and the need to reduce production costs have encouraged the development of alternative approaches. Here, static biological aging was evaluated as a method for producing Fino-type wines with reduced ethanol content. Base wines with ~14% and ~15% (v/v) ethanol were aged for nine months, during which chemical, microbiological, and sensory parameters were analyzed, along with flor veil activity. Lower-ethanol wines showed greater flor activity, with approximately 20 more yeast isolates in the wines with 14% (v/v) ethanol. Higher acetaldehyde levels were detected in these wines, reaching about 377 mg L⁻¹ compared to 230 mg L⁻¹ in the control wines (≥15% v/v ethanol). Significant changes were observed in pH (3.13–3.47 vs. 3.04–3.46), volatile acidity (0.20–0.26 g L⁻¹ vs. 0.31–0.66 g L⁻¹), and several volatile compounds, resulting in chemical and sensory profiles consistent with traditional biologically aged wine. Static biological aging can yield lower-alcohol Fino-style white wines with sensory and chemical attributes comparable to the traditional fortified versions, providing a cost-effective alternative that aligns with evolving consumer preferences.

This study investigates nitrogen metabolism during the middle of the second fermentation in stopped bottles of sparkling wine, focusing on two flor Saccharomyces cerevisiae yeast strains (G1 and N62) isolated from the velum of biologically aged wine. Nitrogen compounds, including amino acids, biogenic amines, and ammonium chloride, were quantified, revealing strain-specific differences in nitrogen utilization and production. Proteomic analysis identified 1053 proteins, with 127 showing significant differences between strains. Strain G1 demonstrated enhanced cell wall remodeling and prioritized nitrogen conservation via arginine and lysine biosynthesis, while strain N62 exhibited increased translational activity and alternative carbon utilization pathways. Notably, strain N62 produced higher concentrations of biogenic amines (putrescine and tyramine), likely due to its greater decarboxylation capacity. Principal Component Analysis (PCA) highlighted clear differentiation in the nitrogen compound profiles across the base wine and wines inoculated with the two strains. The proteome of strain N62 showed increased mitochondrial activity and TCA cycle involvement, facilitating faster fermentation (27 days vs. 52 days for G1), growth (46 × 10⁶ cells/mL vs. 21 × 10⁶ cells/mL for G1) and cell viability (4 × 10⁶ cells/mL vs. 0.7 × 10⁶ cells/mL for G1). These findings suggest that yeast strain selection significantly influences nitrogen metabolism and potentially aroma profiles and and fermentation dynamics in sparkling wine production. Understanding these metabolic adaptations provides valuable insights for optimizing yeast performance to enhance wine quality and preserve regional characteristics.

Yeast biocapsules are a novel immobilization technology that could be used in fermentation processes. They are spherical structures consisting of yeast cells encapsulated and attached to the hyphae of a filamentous fungus. Yeast biocapsules offer a cutting-edge approach to cell immobilization, with significant potential for advancing fermented food production. By enhancing fermentation control, improving product quality, and increasing process efficiency, these biocapsules represent a key innovation in food fermentation technology, particularly in the production of alcoholic beverages such as beer and wine. Proteomic analysis of two-dimensional gels was carried out to study changes in proteins expressed in (i) co-immobilized yeast cells, and (ii) free-format yeast cells. This analysis showed that the proteins expressed in co-immobilized yeast cells played critical roles in DNA repair, cell cycle regulation, protein synthesis, and translation, whereas the proteins expressed by free yeast cells were mainly related to glycolysis. These findings suggest a defense response of the co-immobilized yeast against fungal interactions, involving regulatory mechanisms at the DNA, RNA, and protein levels. This study opens new avenues for exploring yeast–fungus co-immobilization, including stress responses, the nature of the binding polymers, and the proteomics of biocapsules. Additionally, investigating natural co-immobilization mechanisms between various microorganisms could uncover further biotechnological applications and biocatalytic activities.