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Botrytis cinerea is a fungal pathogen that can infect healthy fruits and vegetables, causing significant economic losses through the development of gray mold disease. Over the past few decades, antagonistic yeast has been successfully employed to control this disease. In this study, an exhaustive screening process was conducted on seven yeast strains, ultimately identifying Hanseniaspora uvarum as the strain with the highest antimicrobial activity. Subsequent investigations focused on understanding its inhibitory mechanisms against cucumber gray mold. The results demonstrated that H. uvarum exhibited remarkable suppression of spore germination and germ tube elongation in B. cinerea. Most notably, H. uvarum displayed rapid colonization on the surface of cucumber fruits and effectively curbed the invasion of cucumber gray mold by inducing ROS metabolism, enhancing the activity of disease-resistant enzymes (PPO and POD) and upregulating the expression levels of relevant genes (CsPLA, CsPR1, CsCHI, and CsGLU), while promoting the accumulation of total phenolics and flavonoids. These collective actions served to maintain the storage quality of the fruits. In conclusion, H. uvarum holds significant potential in mitigating the harm caused by cucumber gray mold. [ABSTRACT FROM AUTHOR]

This study explores the potential of indigenous non- Saccharomyces yeasts isolated from Vitis vinifera L. grape skins to improve the quality of regional wines by enhancing their physicochemical and sensory characteristics. Five promising yeast strains were identified at different stages of fermentation: Hanseniaspora opuntiae (J1Y-T1), H. guilliermondii (Y5P-T5), H. uvarum (JF3-T1N), Pichia kudriavzevii (Y8P-T8), and Starmerella bacillaris (WMP4-T4). Among these, H. uvarum and S. bacillaris were particularly noteworthy due to their superior alcohol production, achieving levels of 8.16 ± 0.05% and 8.04 ± 0.04% (v/v), respectively, and demonstrating higher alcohol tolerance even in later fermentation stages. Hanseniaspora uvarum also showed exceptional resilience, with a half-life of 3.34 ± 0.03 days and a Km value of 1.0200 ± 0.0100 mol L⁻¹, achieving the highest biomass even in the later stages of fermentation. High-Performance Liquid Chromatography analysis revealed that while tartaric acid levels remained constant, malic acid content decreased, and acetic acid was produced by all strains. Solid-Phase Microextraction-Gas Chromatography Mass Spectrometry identified ethyl acetate as the dominant volatile compound, with H. uvarum producing the highest concentration (43.411 ± 1.602%), contributing to a fruitier aroma and flavor. The combined attributes of H. uvarum higher alcohol content, enhanced fruity notes, improved clarity, lower acetic acid (0.52 ± 0.03 g L⁻¹), and significant residual sugar (162.37 ± 2.48 g L⁻¹) make it a promising candidate for improving the overall quality of regional wines. Incorporating H. uvarum into mixed starter cultures with specific Saccharomyces strains could further optimize the wine fermentation process. [ABSTRACT FROM AUTHOR]

Chemical control of Drosophila suzukii (Diptera: Drosophilidae) based on the use of insecticides is particularly challenging as the insect attacks ripening fruits shortly before harvest. An alternative strategy may rely on the use of yeasts as phagostimulants and baits, applied on canopy as attract-and-kill formulations. The aim of this research was to identify the most attractive among six yeast species for D. suzukii: Saccharomyces cerevisiae, Hanseniaspora uvarum, Clavispora santaluciae, Saccharomycopsis vini, Issatchenkia terricola, and Metschnikowia pulcherrima. The volatile profile of C. santaluciae was described for the first time. Behavioural experiments identified H. uvarum and S. vini as the most attractive yeasts. The characterization of yeast headspace volatiles using direct headspace (DHS) and solid-phase microextraction (SPME) revealed several strain-specific compounds. With DHS injection, 19 volatiles were characterised, while SPME revealed 71 compounds constituting the yeast headspace. Both analyses revealed terpenoids including β-ocimene, citronellol, (Z)-geraniol (nerol), and geranial as distinct constituents of S. vini. H. uvarum and S. vini were further investigated using closed-loop stripping analysis (CSLA) and electroantennography. Out of 14 compounds quantified by CSLA, ethyl acetate, isoamyl acetate, β-myrcene, benzaldehyde and linalool were detected by D. suzukii antennae and might generate the strong attractiveness of S. vini and H. uvarum. Our results highlight a strong attraction of D. suzukii to various yeasts associated with both the flies and their habitat and demonstrate how different sampling methods can impact the results of volatile compound characterization. It remains to be demonstrated whether the distinct attraction is based on special adaptations to certain yeasts and to what extent the metabolites causing attraction are interchangeable. [ABSTRACT FROM AUTHOR]

In this investigation, we focused on elucidating the impact of non-Saccharomyces yeasts on both the aromatic chemical composition and sensory attributes of red dragon fruit wine. This was achieved through the introduction of Hanseniaspora uvarum or Pichia guilliermondii concurrently with Saccharomyces cerevisiae, employing methodologies encompassing co-inoculation or sequential inoculation. The findings suggested that the combined inoculation of non-Saccharomyces yeasts and S. cerevisiae is capable of modulating the sensory properties of wines. Additionally, varying inoculation methods exerted a significant impact on the aromatic qualities of the wine. Co-inoculation and sequential inoculation of H. uvarum or P. guilliermondii with S. cerevisiae demonstrated a remarkable augmentation in the quantity of volatile chemicals while effectively regulating the number of odor activity value (OAV) > 1 in the wine. Therefore, the utilization of mixed fermentation emerges as a viable strategy for regulating the flavor profile of red dragon wine. This methodology stands as a valuable guideline for making various fruit wines, including red dragon fruit wine. [ABSTRACT FROM AUTHOR]

This study explores the potential of indigenous non-Saccharomyces yeasts isolated from Vitis vinifera L. grape skins to improve the quality of regional wines by enhancing their physicochemical and sensory characteristics. Five promising yeast strains were identified at different stages of fermentation: Hanseniaspora opuntiae (J1Y-T1), H. guilliermondii (Y5P-T5), H. uvarum (JF3-T1N), Pichia kudriavzevii (Y8P-T8), and Starmerella bacillaris (WMP4-T4). Among these, H. uvarum and S. bacillaris were particularly noteworthy due to their superior alcohol production, achieving levels of 8.16 ± 0.05% and 8.04 ± 0.04% (v/v), respectively, and demonstrating higher alcohol tolerance even in later fermentation stages. Hanseniaspora uvarum also showed exceptional resilience, with a half-life of 3.34 ± 0.03 days and a Km value of 1.0200 ± 0.0100 mol L⁻¹, achieving the highest biomass even in the later stages of fermentation. High-Performance Liquid Chromatography analysis revealed that while tartaric acid levels remained constant, malic acid content decreased, and acetic acid was produced by all strains. Solid-Phase Microextraction-Gas Chromatography Mass Spectrometry identified ethyl acetate as the dominant volatile compound, with H. uvarum producing the highest concentration (43.411 ± 1.602%), contributing to a fruitier aroma and flavor. The combined attributes of H. uvarum higher alcohol content, enhanced fruity notes, improved clarity, lower acetic acid (0.52 ± 0.03 g L⁻¹), and significant residual sugar (162.37 ± 2.48 g L⁻¹) make it a promising candidate for improving the overall quality of regional wines. Incorporating H. uvarum into mixed starter cultures with specific Saccharomyces strains could further optimize the wine fermentation process.

Non-Saccharomyces yeasts have great potential in improving wine quality, showing personality characteristics, and highlighting the terroir of wine. In this study, we evaluated the impact of simultaneous inoculation with the non-Saccharomyces yeasts Torulaspora delbrueckii or (and) Hanseniaspora uvarum in combination with Saccharomyces cerevisiae (EC1118 or VL3) on the aromatic compounds and sensory quality of Sauvignon blanc wines. The growth of yeast groups in the alcoholic fermentation process was tracked using fluorescence in situ hybridization. The presence of non-Saccharomyces yeast notably impacted the distribution of S. cerevisiae and was related to the species of yeast. The co-fermentation of H. uvarum and S. cerevisiae improved the content of total esters, especially acetate esters. Simultaneous inoculation of T. delbrueckii or (and) H. uvarum significantly increased the content of total terpenes, especially linalool. Similar results were found for some higher alcohols and organic acids. Sensory evaluation showed that the wines mixed fermentation with H. uvarum had significantly tropical fruit aroma characteristics. Citrus and mineral notes, typical aroma characteristics of Sauvignon blanc wine, were enhanced by mixed fermentation strategies with T. delbrueckii or (and) H. uvarum and different S. cerevisiae. Hence, co-fermentation by T. delbrueckii or H. uvarum combined with S. cerevisiae could significantly improve the sensory quality of Sauvignon blanc wine. [ABSTRACT FROM AUTHOR]

Lignocellulosic biomass as a cheap and abundant raw material offers great advantages in terms of biotechnological applications. The current study aimed to produce bioethanol from mulberry pomace by newly isolated xylose/glucose co-fermenter Hanseniaspora uvarum. For this purpose, the xylose consumption capacity of the yeast was first tested using the synthetic xylose-containing medium as a carbon source, and Hanseniaspora uvarum effectively fermented xylose into ethanol. Afterward, Hansenispora uvarum was used for the fermentation of the liquid hydrolysate obtained by dilute acid pretreatment of mulberry pomace. Furthermore, a subsequent enzymatic hydrolysis of the pretreated mulberry pomace was performed to investigate its effect. For this purpose, initial biomass concentration (50–500 g/L) for fermentation was optimized in two different mulberry pomace media containing nitrogen sources or mineral salts. Enzymatic hydrolysis of pretreated mulberry pomace was performed at 400 g/L initial biomass loading with or without soluble soy protein addition, and a significant increase in fermentable sugar concentrations was observed. The highest sugar concentration was observed as 159.6 g/L when 400 g/L biomass loading was used during dilute acid pretreatment, and subsequent enzymatic hydrolysis was performed using 15 FPU/g cellulose. Moreover, after dilute acid pretreatment and enzymatic hydrolysis, ethanol production of Hanseniaspora uvarum reached 61.3 g/L (0.153 g/gbiomass) which is a sufficient amount for efficient distillation according to literature. Results show that xylose/glucose co-fermenter Hanseniaspora uvarum and mulberry pomace can be considered for second-generation bioethanol production. [ABSTRACT FROM AUTHOR]

Pure, co-, and sequential fermentations of Hanseniaspora uvarum, H. guilliermondii, and Saccharomyces cerevisiae strains were evaluated to improve the aromatic quality of ciders. In sequential fermentations, Hanseniaspora strains were used as starter, followed by S. cerevisiae inoculation succeeding one, two, and three days of fermentation. Kinetics, physicochemical parameters, and volatile compounds were assessed during 10 days of fermentation. The headspace technique was used to capture the volatile compounds from the ciders obtained in each experiment and analyzed by gas chromatography. Fermentations with pure strains of Hansenisaspora sp. showed a high population (>1010 CFU/mL) but had a low fermentation rate (2.3–3.8 CO2 g/L/d), low consumption of amino acids (20–40 mg/L) with a high residual content, high sugar consumption (80–90 g/L), and low alcohol content (<2.0% v/v). The H. uvarum strain produced a notably high ester content (245 mg/L). In the co-fermentations, H. guilliermondii with S. cerevisiae highlighted a significant production of higher alcohols, similar to that produced by S. cerevisiae alone (152–165 mg/L). In general, the maximum fermentation rate of the sequential inoculations was lower than co-fermentations but showed low residual nitrogen content (<69 mg/L) and good conversion of sugars into ethanol (4.3–5.7% v/v). The highest concentrations of volatile compounds were observed in treatments involving the two non-conventional strains: H. uvarum with S. cerevisiae inoculation after three days (564 mg/L) and H. guilliermondii after just one day (531 mg/L) of fermentation. These differences stemmed from the metabolic activity of the strains. H. uvarum was influenced by the presence of Saccharomyces, whereas H. guilliermondii did not exhibit this effect. Thus, a pure H. uvarum inoculum has the potential to produce a demi-sec cider with low alcohol content and high content of esters, contributing to a fruity aroma. In addition, ciders with sequential inoculation were the most promising for dry cider processing concerning fermentation parameters and bioaroma enrichment. [ABSTRACT FROM AUTHOR]

Post-harvest decay of fresh table grapes causes considerable annual production losses. The main fungal agents of decay both in pre- and post-harvest are B. cinerea, Penicillium spp., Aspergillus spp., Alternaria spp., and Cladosporium spp. To date, the use of agrochemicals and SO2 are the main methods to control grape molds in pre- and postharvest, respectively. Significant improvements, however, have already been made in to apply innovative and more environmentally sustainable control strategies, such as Biological Control Agents (BCAs), which can reduce disease severity in both pre- and post-harvest. In this study, 31 new non-Saccharomyces yeast strains, isolated from berries of native Apulian table grape genotypes, were tested for their in vivo effectiveness against grey mold of table grapes, resulting in two St. bacillaris ('N22_I1' and 'S13_I3'), one S. diversa ('N22_I3'), one A. pullulans ('OLB_9.1_VL') and one H. uvarum ('OLB_9.1_BR') yeast strains that were marked as efficient and good BCAs. Their mechanisms of action were characterized through in vitro assays, and additional characteristics were evaluated to assess the economic feasibility and viability for future technological employment. Their effectiveness was tested by reducing the working concentration, their antagonistic effect on a wide range of fungal pathogens, their ability to survive in formulations with long shelf life, and their safety to human health. [ABSTRACT FROM AUTHOR]

Non-Saccharomyces yeasts co-cultivation is one of the techniques to improve complexity of wine aroma profile. However, this strategy is rarely mentioned in the process of fortified wine. The purpose of this study is to use non-Saccharomyces yeasts in Kyoho-fortified wine making and explore the differences through instrumental analysis and sensory evaluation. Three yeast strains, S. cerevisiae Gr112, Hanseniaspora uvarum Pi235 and Pichia kluyveri Pe114 were used during the fermentation process. Then, the wine samples were aged with oak chips for 90 days. Sequential inoculation treatment of wine showed higher esters and terpenes content, which also corresponded to the level of floral and fruity attributes according to respondents. On the other hand, the ageing process provided the wooden aroma compounds such as whiskey lactone and vanillin to Kyoho-fortified wines. Consequently, co-cultivation and ageing could increase aroma variety and complexity which enhance the aroma quality in fortified wines. [ABSTRACT FROM AUTHOR]

Parent‐to‐offspring transmission of beneficial microorganisms is intimately interwoven with the evolution of social behaviors. Ancestral stages of complex sociality–microbe vectoring interrelationships may be characterized by high costs of intensive parental care and hence only a weak link between the transmission of microbial symbionts and offspring production. We investigate the relationship between yeast symbiont transmission and egg‐laying, as well as some general factors thought to drive the "farming" of microscopic fungi by the fruit fly Drosophila melanogaster, an insect with no obvious parental care but which is highly dependent on dietary microbes during offspring development. The process of transmitting microbes involves flies ingesting microbes from their previous environment, storing and vectoring them, and finally depositing them to a new environment. This study revealed that fecal materials of adult flies play a significant role in this process, as they contain viable yeast cells that support larval development. During single patch visits, egg‐laying female flies transmitted more yeast cells than non‐egg‐laying females, suggesting that dietary symbiont transmission is not random, but linked to offspring production. The crop, an extension of the foregut, was identified as an organ capable of storing viable yeast cells during travel between egg‐laying sites. However, the amount of yeast in the crop reduced rapidly during periods of starvation. Although females starved for 24 h deposited a smaller amount of yeast than those starved for 6 h, the yeast inoculum produced still promoted the development of larval offspring. The results of these experiments suggest that female Drosophila fruit flies have the ability to store and regulate the transfer of microorganisms beneficial to their offspring via the shedding of fecal material. We argue that our observation may represent an initial evolutionary stage of maternal care through the manipulation of microbial load, from which more specialized feedbacks of sociality and microbe management may evolve. [ABSTRACT FROM AUTHOR]

Pure, co-, and sequential fermentations of Hanseniaspora uvarum, H. guilliermondii, and Saccharomyces cerevisiae strains were evaluated to improve the aromatic quality of ciders. In sequential fermentations, Hanseniaspora strains were used as starter, followed by S. cerevisiae inoculation succeeding one, two, and three days of fermentation. Kinetics, physicochemical parameters, and volatile compounds were assessed during 10 days of fermentation. The headspace technique was used to capture the volatile compounds from the ciders obtained in each experiment and analyzed by gas chromatography. Fermentations with pure strains of Hansenisaspora sp. showed a high population (>1010 CFU/mL) but had a low fermentation rate (2.3–3.8 CO2 g/L/d), low consumption of amino acids (20–40 mg/L) with a high residual content, high sugar consumption (80–90 g/L), and low alcohol content (v/v). The H. uvarum strain produced a notably high ester content (245 mg/L). In the co-fermentations, H. guilliermondii with S. cerevisiae highlighted a significant production of higher alcohols, similar to that produced by S. cerevisiae alone (152–165 mg/L). In general, the maximum fermentation rate of the sequential inoculations was lower than co-fermentations but showed low residual nitrogen content (v/v). The highest concentrations of volatile compounds were observed in treatments involving the two non-conventional strains: H. uvarum with S. cerevisiae inoculation after three days (564 mg/L) and H. guilliermondii after just one day (531 mg/L) of fermentation. These differences stemmed from the metabolic activity of the strains. H. uvarum was influenced by the presence of Saccharomyces, whereas H. guilliermondii did not exhibit this effect. Thus, a pure H. uvarum inoculum has the potential to produce a demi-sec cider with low alcohol content and high content of esters, contributing to a fruity aroma. In addition, ciders with sequential inoculation were the most promising for dry cider processing concerning fermentation parameters and bioaroma enrichment.

Despite many non‐Saccharomyces yeasts being considered spoilage microorganisms, they can increase aroma and flavor diversity in alcoholic beverages. The purpose of this study was to investigate nontraditional inoculation strategies using aroma‐producing yeast strains for Kyoho wine fermentation, followed by an instrumental analysis and sensory evaluation. The winemaking process was carried out using Saccharomyces cerevisiae Gr112, Hanseniaspora uvarum Pi235, and Pichia kluyveri Pe114. Multiple inoculation strategies were explored. In instrumental analysis results, mixed culture could promote the formation of esters (5.9‐folds) and glycerol (1.3‐folds) and reduce the content of ethanol (–0.5% [v/v]) in wine. The sensory analysis results suggested that the three yeast strains sequential inoculation treatment was associated with the aroma attributes "floral," "red fruity," and "tropical fruity." Co‐cultivation contributed to an increase in complexity and aromatic intensity, with the three‐strain inoculation treatment presenting a more distinctive appearance. Practical Application: The inoculation of S. cerevisiae improved the accumulation of volatile acids and esters by inhibiting the growth of non‐Saccharomyces yeast strains. Inoculation of H. uvarum and P. kluyveri would effectively solve the defect of excessive content of higher alcohols in wines produced by S. cerevisiae. The suitable inoculation strategy between non‐Saccharomyces yeasts could improve the overall quality of Kyoho wine whose starter might be widely used in fermentation industry. [ABSTRACT FROM AUTHOR]

To study the effect of mixed fermentation of non-Saccharomyces strains and Saccharomyces cerevisiae on the aroma quality of 'Italian Riesling' wine in the eastern foothill of Helan Mountain and to determine the most optimum process of mixed fermentation, two selected non-Saccharomyces strains, including Hanseniaspora uvarum YUN268 and Pichia fermentans Z9Y-3, were inoculated with Saccharomyces cerevisiae in different proportions (10:1 or 1:1) and different stages (48 h in advance or simultaneously at the beginning) to ferment 'Italian Riesling' dry white wine. The oenological parameters and aroma indexes of the wine samples were evaluated. The results showed mixed fermentation can not only reduce the alcohol content of wine 0.24~0.71% vol but also increase the glycerol content to improve the taste of wine. The mixed fermentation effect of Pichia fermentans Z9Y-3 and Saccharomyces cerevisiae resulted in improvements, especially the high proportion (10:1) sequential inoculation and simultaneous inoculation of wine samples (WSP10 and WCP10), which not only produced more volatile aroma substances and glycerol content but also increased the total amount of ester substances by 49.4% and 56.5%, respectively, compared with the control. The sensory evaluation scores of WSP10 and WCP10 were significantly higher than the control (89.3 and 88.1 points, respectively). At the same time, it can also enhance the aroma of lemon, cream, almond, and others and increase the aroma complexity of wine. Therefore, these two methods of mixed fermentation inoculation are more suitable for the production of Italian Riesling wine in the eastern foothill of Helan Mountain. In conclusion, the mixed fermentation of Pichia fermentans Z9Y-3 and Saccharomyces cerevisiae 10:1 (simultaneous or sequential) inoculation is suitable for the production of Italian Riesling dry white wine in the eastern foothill of Helan Mountain. [ABSTRACT FROM AUTHOR]

Penicillium expansum is a major postharvest pathogen of apples, causing loss in fruits through tissue damage, as well as in apple products due to contamination with the mycotoxin patulin. During infections, patulin is a cultivar-dependent virulence factor that facilitates apple lesion development. Patulin also has characterized antimicrobial activity and is important for inhibiting other competitive phytopathogens, but the role of this inhibitory activity has not been investigated in the context of the apple microbiome. In our current study, we isolated 68 apple microbiota and characterized their susceptibility to P . expansum extracts. We found gram-negative bacteria and basidiomycete yeast to demonstrate largely patulin-specific growth inhibition compared with gram-positive and ascomycete isolates. From co-cultures, we identified a Hanseniaspora and Gluconobacter pairing that reduced P . expansum biomass and found that H . uvarum alone is sufficient to reduce apple disease progression in vivo. We investigated possible mechanisms of H . uvarum biocontrol activity and found modest inhibition on apple puree plates, as well as a trend toward lower patulin levels at the wound site. Active biocontrol activity required live yeast, which was also effective in controlling Botrytis cinerea apple infections. Lastly, we explored the breadth of H . uvarum biocontrol activity with over 30 H . uvarum isolates and found consistent inhibition of P . expansum apple disease., Competing Interests: The author(s) declare no conflict of interest.

Hanseniaspora uvarum, a non-Saccharomyces cerevisiae species, has a crucial effect on the aroma characteristics of fruit wines, thus, attracting significant research interest in recent years. In this study, H. uvarum–Saccharomyces cerevisiae mixed fermentation was used to ferment Rosa roxburghii Tratt, blueberry fruit wine, and plum fruit wines using either a co-inoculated or a sequentially inoculated approach. The three fruit wines' volatile aroma characteristics were analyzed by headspace–solid-phase microextraction–gas chromatography-mass spectrometry (HS–SPME–GC–MS). The results showed that the mixed inoculation of H. uvarum and S. cerevisiae reduced the alcoholic content of Kongxinli fruit wine. Moreover, H. uvarum–S. cerevisiae fermented Rosa roxburghii Tratt, blueberry, and plum fruit wines and further enriched their flavor compounds. The overall flavor characteristics of sequentially inoculated fruit wines differed significantly from those fermented with S. cerevisiae alone, although several similarities were also observed. Sequential inoculation of H. uvarum and S. cerevisiae positively affected the mellowness of the wine and achieved a better harmony of the overall wine flavors. Therefore, H. uvarum–Saccharomyces cerevisiae mixed fermentation can improve the complexity of the wines' aromatic composition and empower them with a unique identity. In particular, H. uvarum–Saccharomyces cerevisiae blueberry wine produced by mixed fermentation had the widest variety and content of aroma compounds among the fermented wines. Therefore, H. uvarum–Saccharomyces cerevisiae mixed-fermentation inoculation in the three fermented fruit wines significantly increased the aroma compound variety and content, thus, enriching their aroma richness and complexity. This study is the first comparative evaluation of the aroma characteristics of different fruit wines fermented with a mixed inoculation of H. uvarum and S. cerevisiae and provides a preliminary guide for these fruit wines produced with non-Saccharomyces yeast. [ABSTRACT FROM AUTHOR]

Biological control by antagonistic microorganisms are an effective and environmentally friendly approach in postharvest disease management. In order to develop a biocontrol agent for fresh walnut fruit preservation, the potential biocontrol effects of Bacillus amyloliquefaciens RD.006 and Hanseniaspora uvarum FA.006 against the main fungal pathogen of walnuts were evaluated. Botryosphaeria species showed the highest detection, and the JNHT01 strain showed the strongest pathogenicity. Bot. dothidea JNHT01 caused gray mold and brown rot on fresh walnuts, and its incidence rate reached 100% after an 8 days incubation. The growth of this fungal strain can be promoted by lighting, with a maximum growth rate achieved at a pH of 7 and at 28 °C. B. amyloliquefaciens RD.006 and H. uvarum FA.006 supernatants at a concentration of 1–15% v/v showed antifungal activity. The mycelial growth inhibition rates of Bot. dothidea JNHT01 were 23.67–82.61% for B. amyloliquefaciens RD.006 and 1.45–21.74% for H. uvarum FA.006. During Bot. dothidea JNHT01 growth, the biomass, nucleic acid leakage, and malondialdehyde content gradually increased, while the DPPH scavenging capacity and SOD activity decreased. The B. amyloliquefaciens RD.006 and H. uvarum FA.006 strains showed antifungal activity by damaging fungal cell membranes and reducing fungal antioxidant activity. Moreover, the antifungal effect of B. amyloliquefaciens RD.006 was higher than that of H. uvarum FA.006. Hence, the RD.006 strain of B. amyloliquefaciens can be considered a potential biocontrol agent for the management of postharvest walnut diseases caused by Bot. dothidea. [ABSTRACT FROM AUTHOR]

In this study, an oomycete strain FQ01 of Phytophthora nicotianae, which could cause destructive postharvest disease, was isolated. At present, chemical fungicides are themain reagents used for controlling Phytophthora diseases. It is necessary to find new control techniques that are environmentally friendly. The biocontrol activity of Hanseniaspora uvarumMP1861 against P. nicotianae FQ01 was therefore investigated. Our results revealed that the volatile organic compounds (VOCs) released by the yeast strain MP1861 could inhibit the development of P. nicotianae FQ01. The major component of the VOCs produced by the yeast strainMP1861 was identified to be ethyl acetate (70.8%). Biocontrol experiments showed that Phytophthora disease in tomato fruit could be reduced by 95.8% after the yeast VOCs treatment. Furthermore, ethyl acetate inhibited the mycelial growth of the oomycete strain FQ01, and damaged the pathogen cell membrane. This paper describes the pioneering utilization of the yeast strain MP1861 for biocontrol of postharvest fruit rot in tomato caused by P. nicotianae. [ABSTRACT FROM AUTHOR]

The oriental fruit fly, Bactrocera dorsalis (Diptera: Tephritidae) is a destructive horticultural pest which causes considerable economic losses every year. A collection of microorganisms live within the B. dorsalis gut, and they are involved in its development, physiology, and behavior. However, knowledge regarding the composition and function of the gut mycobiota in B. dorsalis are still limited. Here, we comprehensively characterized the gut mycobiota in B. dorsalis across different developmental stages. High‐throughput sequencing results showed a significant difference in fungal species abundance and diversity among different developmental stages of B. dorsalis. Quantitative polymerase chain reaction and culture‐dependent methods showed that yeast species was the dominant group in the larval stage. We isolated 13 strains of yeast from the larval gut, and found that GF (germ‐free) larvae mono‐associated with strain Hanseniaspora uvarum developed faster than those mono‐associated with other tested fungal strains. Supplementing the larval diet with H. uvarum fully rescued B. dorsalis development, shortened the larval developmental time, and increased adult wing lengths, as well as the body sizes and weights of both pupae and adults. Thus, our study highlights the close interactions between gut fungi, especially H. uvarum, and B. dorsalis. These findings can be applied to the sterile insect technique program to promote host development during mass insect rearing. [ABSTRACT FROM AUTHOR]

Winemaking involves a wide diversity of microorganisms with different roles in the process. The wine microbial consortium (WMC) includes yeasts, lactic acid bacteria and acetic acid bacteria with different implications regarding wine quality. Despite this technological importance, their origin, prevalence, and routes of dissemination from the environment into the winery have not yet been fully unraveled. Therefore, this study aimed to evaluate the WMC diversity and incidence associated with vineyard environments to understand how wine microorganisms overwinter and enter the winery during harvest. Soils, tree and vine barks, insects, vine leaves, grapes, grape musts, and winery equipment were sampled along four seasons. The isolation protocol included: (a) culture-dependent microbial recovery; (b) phenotypical screening to select fermenting yeasts, lactic acid, and acetic acid bacteria; and (c) molecular identification. The results showed that during all seasons, only 11.4% of the 1424 isolates presumably belonged to the WMC. The increase in WMC recovery along the year was mostly due to an increase in the number of sampled sources. Acetic acid bacteria (Acetobacter spp., Gluconobacter spp., Gluconoacetobacter spp.) were mostly recovered from soils during winter while spoilage lactic acid bacteria (Leuconostoc mesenteroides and Lactobacillus kunkeii) were only recovered from insects during véraison and harvest. The fermenting yeast Saccharomyces cerevisiae was only isolated from fermented juice and winery equipment. The spoilage yeast Zygosaccharomyces bailii was only recovered from fermented juice. The single species bridging both vineyard and winery environments was the yeast Hanseniaspora uvarum, isolated from insects, rot grapes and grape juice during harvest. Therefore, this species appears to be the best surrogate to study the dissemination of the WMC from vineyard into the winery. Moreover, the obtained results do not evidence the hypothesis of a perennial terroir-dependent WMC given the scarcity of their constituents in the vineyard environment along the year and the importance of insect dissemination. [ABSTRACT FROM AUTHOR]

Non- Saccharomyces (NS) yeasts with high β -glucosidase activity play a vital role in improving the aroma complexity of wines by releasing aroma compounds from glycosidic precursors during fermentation. In this study, the effect of sequential inoculation fermentation of Meyerozyma guilliermondii NM218 and Hanseniaspora uvarum BF345 with two Saccharomyces cerevisiae strains [Vintage Red™ (VR) and Aroma White™ (AW)] on volatile compounds and sensory characteristics of wines was investigated. Prior to winemaking trials, the sequential inoculation times of the two NS yeasts were evaluated in synthetic must, based on changes in strain population and enzyme activity. The intervals for inoculation of NM218 and BF345 with the S. cerevisiae strains were 48 and 24 h, respectively. In the main experiment, sequential inoculation fermentations of the two strains with S. cerevisiae were carried out in Cabernet Sauvignon (CS) and Chardonnay (CH) grape must. The oenological parameters, volatile composition, and sensory characteristics of the final wines were assessed. No clear differences were observed in the oenological parameters of the sequentially fermented CH wines compared with the control, except for residual sugar and alcohol. However, in CS wines, the total acid contents were significantly lower in the wines fermented by sequential inoculation compared to the control. Both NM218 and BF345 improved the aroma complexity of wines by increasing esters and terpenes when inoculated with S. cerevisiae strains compared to inoculation with S. cerevisiae strains alone. NM218 resulted in a more positive effect on CS wine aroma, with higher levels of citronellol and trans -nerolidol. BF345 significantly enhanced the floral and fruity aromas of CH wine by producing higher concentrations of geranyl acetone, β -damascenone, trans -nerolidol, and nerol. Both NM218 and BF345 yeasts could potentially be used to improve wine aroma and overall quality, especially wine floral and fruity aromas, when used in sequential inoculation with S. cerevisiae. [ABSTRACT FROM AUTHOR]

The application of β-glucosidase from non-Saccharomyces yeasts to improve wine aroma has been widely explored. However, few enzymes are active under the severe conditions of wine aging (high ethanol concentration, low temperature, and low pH). Therefore, the application of β-glucosidase in wine aging needs further research. In this study, the β-glucosidases Mg-βgl and Hu-βgl extracted from Meyerozyma guilliermondii NM218 and Hanseniaspora uvarum BF345 were purified and used in young Chardonnay wines aged for 50 days. The enzyme activity of the two enzymes was measured. The effects of the two enzymes and a commercial β-glucosidase (An-βgl) on the volatile composition and sensory quality of the wine were also determined. The results showed that Mg-βgl and Hu-βgl had high specific activity of 1.95 U/mg and 2.11 U/mg, respectively, maintaining the activity of 70–80% at 20 °C, pH of 3.0–4.0, and 15% ethanol, corresponding to wine aging conditions. Analysis of volatiles with GC-MS showed a 65–70% increase in total terpenoids and new detection of C13-norisoprenoids when the wines were treated with the three β-glucosidases. In addition, wines treated with Mg-βgl and Hu-βgl had more hexanol, phenylethanol, ethyl octanoate, ethyl heptanoate, and ethyl caprate than wines treated without and with An-βgl. In sensory analysis, the judges showed a greater preference for Hu-βgl-treated wines, to which they attributed pleasant sweet, floral, honey, pomelo, and banana aromas. The results of this study not only offer a way to improve flavor complexity in wine but also provide a reference for the use of other edible sources of β-glucosidase in wine aging. [ABSTRACT FROM AUTHOR]

Non-Saccharomyces (NS) yeasts with high β-glucosidase activity play a vital role in improving the aroma complexity of wines by releasing aroma compounds from glycosidic precursors during fermentation. In this study, the effect of sequential inoculation fermentation of Meyerozyma guilliermondii NM218 and Hanseniaspora uvarum BF345 with two Saccharomyces cerevisiae strains [Vintage Red™ (VR) and Aroma White™ (AW)] on volatile compounds and sensory characteristics of wines was investigated. Prior to winemaking trials, the sequential inoculation times of the two NS yeasts were evaluated in synthetic must, based on changes in strain population and enzyme activity. The intervals for inoculation of NM218 and BF345 with the S. cerevisiae strains were 48 and 24 h, respectively. In the main experiment, sequential inoculation fermentations of the two strains with S. cerevisiae were carried out in Cabernet Sauvignon (CS) and Chardonnay (CH) grape must. The oenological parameters, volatile composition, and sensory characteristics of the final wines were assessed. No clear differences were observed in the oenological parameters of the sequentially fermented CH wines compared with the control, except for residual sugar and alcohol. However, in CS wines, the total acid contents were significantly lower in the wines fermented by sequential inoculation compared to the control. Both NM218 and BF345 improved the aroma complexity of wines by increasing esters and terpenes when inoculated with S. cerevisiae strains compared to inoculation with S. cerevisiae strains alone. NM218 resulted in a more positive effect on CS wine aroma, with higher levels of citronellol and trans-nerolidol. BF345 significantly enhanced the floral and fruity aromas of CH wine by producing higher concentrations of geranyl acetone, β-damascenone, trans-nerolidol, and nerol. Both NM218 and BF345 yeasts could potentially be used to improve wine aroma and overall quality, especially wine floral and fruity aromas, when used in sequential inoculation with S. cerevisiae.

To study the effect of mixed fermentation of non-Saccharomyces strains and Saccharomyces cerevisiae on the aroma quality of ‘Italian Riesling’ wine in the eastern foothill of Helan Mountain and to determine the most optimum process of mixed fermentation, two selected non-Saccharomyces strains, including Hanseniaspora uvarum YUN268 and Pichia fermentans Z9Y-3, were inoculated with Saccharomyces cerevisiae in different proportions (10:1 or 1:1) and different stages (48 h in advance or simultaneously at the beginning) to ferment ‘Italian Riesling’ dry white wine. The oenological parameters and aroma indexes of the wine samples were evaluated. The results showed mixed fermentation can not only reduce the alcohol content of wine 0.24~0.71% vol but also increase the glycerol content to improve the taste of wine. The mixed fermentation effect of Pichia fermentans Z9Y-3 and Saccharomyces cerevisiae resulted in improvements, especially the high proportion (10:1) sequential inoculation and simultaneous inoculation of wine samples (WSP10 and WCP10), which not only produced more volatile aroma substances and glycerol content but also increased the total amount of ester substances by 49.4% and 56.5%, respectively, compared with the control. The sensory evaluation scores of WSP10 and WCP10 were significantly higher than the control (89.3 and 88.1 points, respectively). At the same time, it can also enhance the aroma of lemon, cream, almond, and others and increase the aroma complexity of wine. Therefore, these two methods of mixed fermentation inoculation are more suitable for the production of Italian Riesling wine in the eastern foothill of Helan Mountain. In conclusion, the mixed fermentation of Pichia fermentans Z9Y-3 and Saccharomyces cerevisiae 10:1 (simultaneous or sequential) inoculation is suitable for the production of Italian Riesling dry white wine in the eastern foothill of Helan Mountain.

Drosophila suzukii is a major pest of soft fruits, laying eggs in fruit before it is harvested. Control remains dependent on routine applications of insecticides. In semi‐field experiments, we tested the possibility of reducing the amount of insecticide needed to control D. suzukii by combining lower rates, volumes and area of application, in combination with phagostimulant baits in comparison with full field rates of the insecticides and an untreated control. The baits were (1) Combi‐protec—a proprietary mixture of plant extract, proteins and sugars, (2) a suspension of the yeast Hanseniaspora uvarum and (3) molasses. Low insecticide rates were 4% of the full rates and were attained by diluting the insecticide concentration in the spray and reducing the sprayed volume. The low rate was applied as a coarse quality spray in a swath across the middle of the strawberry or raspberry crop. The full rate was applied as fine droplets to the entire crop canopy. In strawberry, the Combi‐protec with a low rate of cyantraniliprole resulted in the same level of control of D. suzukii as the full rate. Combi‐protec was a more effective bait than the H. uvarum suspension. In raspberry, the average spray deposit coverage on the crop was approximately eight times higher with the full rate application compared with the low rate application. However, low rates of cyantraniliprole and spinosad with Combi‐protec or molasses baits were equally effective in D. suzukii control compared with the full rates of insecticides. In raspberry, the cost of the four full rate sprays of insecticides was £74 ha‐1 or £314 ha‐1 more than the four low rate insecticide sprays with Combi‐protec or molasses, respectively. The low rates of application resulted in fruit insecticide residues being less than 11% of those from raspberries sprayed with the full rates. [ABSTRACT FROM AUTHOR]

This study aimed to assess the impact of different fermentation lees on enhancing the chemical composition, volatile profile, and sensory characteristics of wine during aging, specifically in relation to autolysis induction treatments. Lees processed by high hydrostatic pressure, especially those obtained from sequential fermentation (Hanseniaspora spp. followed by Saccharomyces spp.) determined the best color evolution, the highest protection against oxidation together with an overall improvement of volatile profile; these aged wines also obtained the highest scores in floral and fruity notes, resulting the most preferred by the panel. An improvement of the overall wine quality might be reached, by modulating lees composition (i.e. , non- Saccharomyces spp. as fermentation co-starters), then by applying high hydrostatic pressure as alternative to enzyme addition for managing the subsequent aging on lees. This might possibly implement and improve the current winemaking process with an innovative, sustainable approach. [ABSTRACT FROM AUTHOR]

Hanseniaspora uvarum were isolated and characterized from various local environments to assess their production of fermentation-related enzymes, including β-glucosidase, esterase, pectinase and protease. Four H. uvarum strains with high enzyme activities were selected for further evaluation of their impact on Cabernet Sauvignon wines by analyzing enological parameters and untargeted metabolomics. Results showed that GS29 and GS38 strains improved aroma diversity and taste characteristics in co-fermentation, while GS36 strain only enhanced aromatic intensity and complexity. Metabolomics revealed that compared to S. cerevisiae , H. uvarum strains popularly reduced intermediate metabolites in glycolysis and TCA cycle, consumed more polypeptides, amino acids, and nucleotides, altered polyphenolic composition ratios, and decreased indole and derivatives. Our study highlights the application of three H. uvarum strains in co-fermentation to improve wine quality and provides insights into the metabolic regulation of each H. uvarum during co-fermentation like by adding intermediate metabolites or precursors. [Display omitted] • H. uvarum GS36 strain enhanced aromatic intensity and complexity of red wine. • H. uvarum GS29 and GS38 strains improved aroma diversity and taste characteristics. • H. uvarum strains popularly reduced intermediate metabolites in glycolysis and TCA cycle. • H. uvarum strains consumed more polypeptides, amino acids, and nucleotides than S. cerevisiae. • H. uvarum strains altered polyphenolic composition ratios and decreased indole derivatives. [ABSTRACT FROM AUTHOR]

Yeast derivatives are winemaking additives generally obtained from Saccharomyces spp., commonly used as fermentation and wine quality enhancers. Even though they are widely used, the production process - from initial biomass to their final composition, is not standardized and often not specific for winemaking purposes. In the present study, biomass production was performed by applying different temperatures and agitation conditions, to assess their effect on the chemical composition of the resulting derivatives, using S. cerevisiae and H. uvarum as starting microorganisms. The application of shaking mostly affected the chemical composition of yeast derivatives, resulting in the highest mean concentration of amino acids (146 mg/g in S. cerevisiae), polysaccharides (370 mg/g in H. uvarum), and glutathione (about 85 μmol/g in S. cerevisiae). Derivatives obtained from H. uvarum were characterized by a non-negligible amount of glutathione (35.6 μmol/g - 53.1 μmol/g) and cysteine (12.7 μmol/g - 26.2 μmol/g), regardless of the growth conditions previously applied; only for this strain, reducing proteins linked to cell wall residues were detected. The results obtained suggest that the chemical composition of yeast derivatives may be managed during biomass production, also using specific strains, thus possibly obtaining products naturally rich in compounds of enological interest. • Chemical composition of yeast derivatives may be managed during biomass propagation. • Agitation mostly affected amino acids, polysaccharides and antioxidants content. • Considerable concentration of antioxidants was found in derivatives from H. uvarum. • Derivatives for winemaking may be obtained combining growth conditions and strain. [ABSTRACT FROM AUTHOR]

Biological control by antagonistic microorganisms are an effective and environmentally friendly approach in postharvest disease management. In order to develop a biocontrol agent for fresh walnut fruit preservation, the potential biocontrol effects of Bacillus amyloliquefaciens RD.006 and Hanseniaspora uvarum FA.006 against the main fungal pathogen of walnuts were evaluated. Botryosphaeria species showed the highest detection, and the JNHT01 strain showed the strongest pathogenicity. Bot. dothidea JNHT01 caused gray mold and brown rot on fresh walnuts, and its incidence rate reached 100% after an 8 days incubation. The growth of this fungal strain can be promoted by lighting, with a maximum growth rate achieved at a pH of 7 and at 28 °C. B. amyloliquefaciens RD.006 and H. uvarum FA.006 supernatants at a concentration of 1–15% v/v showed antifungal activity. The mycelial growth inhibition rates of Bot. dothidea JNHT01 were 23.67–82.61% for B. amyloliquefaciens RD.006 and 1.45–21.74% for H. uvarum FA.006. During Bot. dothidea JNHT01 growth, the biomass, nucleic acid leakage, and malondialdehyde content gradually increased, while the DPPH scavenging capacity and SOD activity decreased. The B. amyloliquefaciens RD.006 and H. uvarum FA.006 strains showed antifungal activity by damaging fungal cell membranes and reducing fungal antioxidant activity. Moreover, the antifungal effect of B. amyloliquefaciens RD.006 was higher than that of H. uvarum FA.006. Hence, the RD.006 strain of B. amyloliquefaciens can be considered a potential biocontrol agent for the management of postharvest walnut diseases caused by Bot. dothidea.

Oenological yeasts play a crucial role in the winemaking process by converting sugar into ethanol, carbon dioxide and flavor substances that contribute to the wine aroma profile. Eighty strains of yeast were isolated from Rosa roxburghii Tratt. Three of the indigenous yeast strains (numbered as C26, C31 and F110) were selected based on having the strongest fruity-aroma producing ability to further evaluate theirs oenological properties, and they were identified as Hanseniaspora uvarum based on morphological and molecular analyses. Strains tolerance results showed that the selected strains have glucose, citric acid and sulfur dioxide tolerances that are comparable to commercial Saccharomyces cerevisiae X16, but they are ethanol sensitive. Additionally, the H. uvarum strains had similar β-glucosidase production abilities to the control, but they do not produce hydrogen sulfide. Moreover, the selected H. uvarum strains reduced the acidity and increased the volatile aroma richness and complexity of R. roxburghii wine during laboratory-scale fermentation. Thus, the selected H. uvarum strains (C26, C31 and F110) show potential in the production of unique R. roxburghii wine. [ABSTRACT FROM AUTHOR]

Quality of plum jerkum is significantly associated to the profile of volatile compounds. Therefore, we decided to assess the impact of various fermentation types on selected properties of plum jerkums, especially compounds which contribute to the aroma of the finished product. We used the following yeast strains: S. cerevisiae S1, H. uvarum H2, and Ethanol RED (S. cerevisiae). Moreover, we considered spontaneous fermentation. S. cerevisiae and H. uvarum strains were isolated during the fermentation of Čačanska Lepotica or Węgierka Dąbrowicka (plum cultivars), respectively. As for fermentation type, spontaneous fermentation of H. uvarum H2 provided the best results. It could be associated to the fact that plum juices fermented with H. uvarum H2 presented the highest concentration of terpenoids, esters, or some higher alcohols. In the current paper, application of indigenous strains of yeasts resulted in the required oenological characteristics, e.g., highest fermentation efficiency and concentration of ethanol was determined in juices fermented with Ethanol RED (S. cerevisiae) and also with S. cerevisiae S1. Our results suggested that indigenous strains of yeasts present in plums demonstrate great potential for the production of plum jerkums of high quality. [ABSTRACT FROM AUTHOR]

This review focuses on autochthonous wine yeasts that occur naturally in a specific geographical area, and their role in wine production. The distribution of individual species changes during ripening and processing of grapes and fermentation of the grape must. The composition of autochthonous microflora is influenced by many factors including interspecific interactions. Autochthonous yeast populations lend to wine flavor and taste typical for a specific geographical area. The article describes the fermentation of grape must, changes of autochthonous yeast microflora during spontaneous or combined fermentation, and includes an overview of the basic species of autochthonous yeasts.

The application of β-glucosidase from non-Saccharomyces yeasts to improve wine aroma has been widely explored. However, few enzymes are active under the severe conditions of wine aging (high ethanol concentration, low temperature, and low pH). Therefore, the application of β-glucosidase in wine aging needs further research. In this study, the β-glucosidases Mg-βgl and Hu-βgl extracted from Meyerozyma guilliermondii NM218 and Hanseniaspora uvarum BF345 were purified and used in young Chardonnay wines aged for 50 days. The enzyme activity of the two enzymes was measured. The effects of the two enzymes and a commercial β-glucosidase (An-βgl) on the volatile composition and sensory quality of the wine were also determined. The results showed that Mg-βgl and Hu-βgl had high specific activity of 1.95 U/mg and 2.11 U/mg, respectively, maintaining the activity of 70–80% at 20 °C, pH of 3.0–4.0, and 15% ethanol, corresponding to wine aging conditions. Analysis of volatiles with GC-MS showed a 65–70% increase in total terpenoids and new detection of C13-norisoprenoids when the wines were treated with the three β-glucosidases. In addition, wines treated with Mg-βgl and Hu-βgl had more hexanol, phenylethanol, ethyl octanoate, ethyl heptanoate, and ethyl caprate than wines treated without and with An-βgl. In sensory analysis, the judges showed a greater preference for Hu-βgl-treated wines, to which they attributed pleasant sweet, floral, honey, pomelo, and banana aromas. The results of this study not only offer a way to improve flavor complexity in wine but also provide a reference for the use of other edible sources of β-glucosidase in wine aging.

Background. The geographic and temporal distributions of bacterial and fungal populations are poorly understood within the same wine grape cultivar. In this work, we describe the microbial composition from 'Pinot noir' must with respect to vintage, growing region, climate, and must chemistry across the states of California and Oregon, USA. Materials and Methods. We sampled 'Pinot noir' clone 667 clusters from 15 vineyards existing in a latitudinal gradient spanning nearly 1,200 km in California and Oregon for two vintages (2016 and 2017). Regions included five American Viticultural Areas (AVA). In order from southern California to Oregon, these AVAs were Santa Barbara, Monterey, Sonoma, Mendocino, and Willamette Valley. Uninoculated grape musts were subjected to 16S rRNA gene and ITS-1 amplicon sequencing to assess composition of microbial communities. We also measured grape maturity metrics. Finally, to describe regions by precipitation and growing degree days, we queried the Parameterelevation Regressions on Independent Slopes Model (PRISM) spatial climate dataset. Results. Most of the dominant bacterial taxa in must samples were in the family Enterobacteriaceae, notably the lactic acid bacteria or the acetic acid bacteria groups, but some, like the betaproteobacterial genus Massilia, belonged to groups not commonly found in grape musts. Fungal communities were dominated by Hanseniaspora uvarum (Saccharomycetaceae). We detected relationships between covariates (e.g., vintage, precipitation during the growing season, pH, titratable acidity, and total soluble solids) and bacterial genera Gluconobacter and Tatumella in the family Enterobacteraceae, Sphingomonas (Sphingomonodaceae), Lactobacillus (Lactobacillaceae), and Massilia (Oxalobacteraceae), as well as fungal genera in Hanseniaspora, Kazachstania, Lachancea, Torulaspora in the family Saccharomycetaceae, as well as Alternaria (Pleosporaceae), Erysiphe (Erysiphaceae), and Udeniomyces (Cystofilobasidiaceae). Fungal community distances were significantly correlated with geographic distances, but this was not observed for bacterial communities. Climate varied across regions and vintages, with growing season precipitation ranging from 11mmto 285mmand growing degree days ranging from 1,245 to 1,846. Discussion. We determined that (1) bacterial beta diversity is structured by growing season precipitation, (2) fungal beta diversity reflects growing season precipitation and growing degree days, and (3) microbial differential abundances of specific genera vary with vintage, growing season precipitation, and fruit maturity metrics. Further, the correlation between fungal community dissimilarities and geographic distance suggests dispersal limitation and the vineyard as a source for abundant fungal taxa. Contrasting this observation, the lack of correlation between bacterial community dissimilarity and geographic distance suggests that environmental filtering is shaping these communities. [ABSTRACT FROM AUTHOR]

The growing trend in the wine industry is the revaluation of the role of non‐Saccharomyces yeasts, promoting the use of these yeasts in association with Saccharomyces cerevisiae. Non‐Saccharomyces yeasts contribute to improve wine complexity and organoleptic composition. However, the use of mixed starters needs to better understand the effect of the interaction between these species during alcoholic fermentation. The aim of this study is to evaluate the influence of mixed starter cultures, composed by combination of different S. cerevisiae and Hanseniaspora uvarum strains, on wine characteristics and to investigate the role of cell‐to‐cell contact on the metabolites produced during alcoholic fermentation. In the first step, three H. uvarum and two S. cerevisiae strains, previously selected, were tested during mixed fermentations in natural red grape must in order to evaluate yeast population dynamics during inoculated fermentation and influence of mixed starter cultures on wine quality. One selected mixed starter was tested in a double‐compartment fermentor in order to compare mixed inoculations of S. cerevisiae/H. uvarum with and without physical separation. Our results revealed that physical contact between S. cerevisiae and H. uvarum affected the viability of H. uvarum strain, influencing also the metabolic behaviour of the strains. Although different researches are available on the role of cell‐to‐cell contact‐mediated interactions on cell viability of the strains included in the mixed starter, to our knowledge, very few studies have evaluated the influence of cell‐to‐cell contact on the chemical characteristics of wine. [ABSTRACT FROM AUTHOR]

Yeasts play an important role in the life cycle and biology of the insect pest Drosophila suzukii (Matsumura), commonly known as the spotted wing drosophila (SWD). Adult and larvae of this species are known to feed and benefit from yeast in their diet. In addition, yeasts were found to be attractive to SWD and were repeatedly found to be associated with SWD. Among those, Hanseniaspora uvarum is the most commonly mentioned. The present study explores the chemical composition and the effects of three H. uvarum strains and five yeast species (Saccharomyces cerevisiae, Candida sp., Issatchenkia terricola, Metschnikowia pulcherrima and Saccharomycopsis vini) in the diet of SWD adults. The different yeast species used in this study influenced mortality, fecundity and ingestion by SWD females. Hanseniaspora uvarum and S. vini were preferably ingested and increased fecundity of SWD females. The intra- and extracellular concentrations of compounds, such as amino acids, carbohydrates, sugar alcohols and organic acids, produced or consumed by yeasts differed among the species. Knowledge of the interaction of different yeast species with SWD and specific differences in the profile of compounds of yeast can help to improve the development of control strategies against the insect pest by promoting the ingestion of attract-and-kill formulations based on the combinations of yeasts and an appropriate insecticide. [ABSTRACT FROM AUTHOR]

The utilization of native yeast strains associated with a distinct terroir for autochthonous grape types represents a novel trend in winemaking, contributing to the production of unique wines with regional character. Hence, this study aimed to isolate native strains of the yeast H. uvarum from the surface of various fruits and to characterize its fermentation capability in Prokupac grape must. Out of 31 yeasts, 8 isolates were identified as H. uvarum. The isolates were able to grow at low (4 °C) temperatures, SO2 concentrations up to 300 ppm and ethanol concentrations up to 5%. Additionally, they provided a good profile of organic acids during the microvinification of sterile grape must. Although the content of acetic acid (0.54–0.63 g/L) was relatively high, the sniffing test proved that the yeast isolates developed a pleasant aroma characterized as fruity. All H. uvarum isolates produced twice the concentration of glycerol compared to commercial wine yeast Saccharomyces cerevisiae, contributing to the fullness and sweetness of the wine. The results for pure and sequential fermentation protocols confirmed that the selected S-2 isolate has good oenological characteristics, the capability to reduce the ethanol content (up to 1% v/v) and a potential to give a distinctive note to Prokupac-grape wines.

The occurrence of mycotoxins on grapes poses a high risk for food safety; thus, it is necessary to implement effective prevention methods. In this work, a metagenomic approach revealed the presence of important mycotoxigenic fungi in grape berries, including Aspergillus flavus, Aspergillus niger aggregate species, or Aspergillus section Circumdati. However, A. carbonarius was not detected in any sample. One of the samples was not contaminated by any mycotoxigenic species, and, therefore, it was selected for the isolation of potential biocontrol agents. In this context, Hanseniaspora uvarum U1 was selected for biocontrol in vitro assays. The results showed that this yeast is able to reduce the growth rate of the main ochratoxigenic and aflatoxigenic Aspergillus spp. occurring on grapes. Moreover, H. uvarum U1 seems to be an effective detoxifying agent for aflatoxin B1 and ochratoxin A, probably mediated by the mechanisms of adsorption to the cell wall and other active mechanisms. Therefore, H. uvarum U1 should be considered in an integrated approach to preventing AFB1 and OTA in grapes due to its potential as a biocontrol and detoxifying agent.

A current trend in winemaking has highlighted the beneficial contribution of non-Saccharomyces yeasts to wine quality. Hanseniaspora uvarum is one of the more represented non-Saccharomyces species onto grape berries and plays a critical role in influencing the wine sensory profile, in terms of complexity and organoleptic richness. In this work, we analyzed a group of H. uvarum indigenous wine strains as for genetic as for technological traits, such as resistance to SO2 and β-glucosidase activity. Three strains were selected for genome sequencing, assembly and comparative genomic analyses at species and genus level. Hanseniaspora genomes appeared compact and contained a moderate number of genes, while rarefaction analyses suggested an open accessory genome, reflecting a rather incomplete representation of the Hanseniaspora gene pool in the currently available genomes. The analyses of patterns of functional annotation in the three indigenous H. uvarum strains showed distinct enrichment for several PFAM protein domains. In particular, for certain traits, such as flocculation related protein domains, the genetic prediction correlated well with relative flocculation phenotypes at lab-scale. This feature, together with the enrichment for oligo-peptide transport and lipid and amino acid metabolism domains, reveals a promising potential of these indigenous strains to be applied in fermentation processes and modulation of wine flavor and aroma. This study also contributes to increasing the catalog of publicly available genomes from H. uvarum strains isolated from natural grape samples and provides a good roadmap for unraveling the biodiversity and the biotechnological potential of these non-Saccharomyces yeasts.

Hanseniaspora, a predominant yeast genus of grape musts, includes sister species recently reported as fast evolving. The aim of this study was to investigate the genetic relationships between the four most closely related species, at the population level. A multi-locus sequence typing strategy based on five markers was applied on 107 strains, confirming the clear delineation of species H. uvarum, H. opuntiae, H. guilliermondii, and H. pseudoguilliermondii. Huge variations were observed in the level of intraspecific nucleotide diversity, and differences in heterozygosity between species indicate different life styles. No clear population structure was detected based on geographical or substrate origins. Instead, H. guilliermondii strains clustered into two distinct groups, which may reflect a recent step toward speciation. Interspecific hybrids were detected between H. opuntiae and H. pseudoguilliermondii. Their characterization using flow cytometry, karyotypes and genome sequencing showed different genome structures in different ploidy contexts: allodiploids, allotriploids, and allotetraploids. Subculturing of an allotriploid strain revealed chromosome loss equivalent to one chromosome set, followed by an auto-diploidization event, whereas another auto-diploidized tetraploid showed a segmental duplication. Altogether, these results suggest that Hanseniaspora genomes are not only fast evolving but also highly dynamic.

Multi-starter wine fermentations employing non-Saccharomyces (NS) yeasts are becoming an emerging trend in winemaking. It is therefore important to determine the impacts of different NS strains in the wine phenotype and in particular the aroma outputs in different inoculation schemes and fermentation conditions. Here, two native NS yeasts, Lachancea thermotolerans LtMM7 and Hanseniaspora uvarum HuMM19, were assessed for their ability to improve the quality of Moschofilero, a Greek aromatic white wine. The NS strains were initially examined in laboratory scale fermentations in mixed inoculations with ScMM23, a native Saccharomyces cerevisiae strain. LtMM7 was selected to be further evaluated in pilot scale fermentations. Five different inoculation schemes were considered: single inoculation of ScMM23 (IS), simultaneous inoculation of ScMM23 with HuMM19 (SMH) or LtMM7 (SML), and sequential inoculation of HuMM19 (SQH) or LtMM7 (SQL) followed by ScMM23. At laboratory scale fermentations, the chemical profiles were largely affected by both the NS species and the inoculation scheme applied. The sequential inoculation using HuMM19 produced the most divergent wine phenotype. However, HuMM19 caused significant increases in acetic acid and ethyl acetate levels that impeded its use in pilot scale trials. LtMM7 significantly affected the chemical profiles of wines produced at the winery, especially in the sequential inoculation scheme. Importantly, LtMM7 significantly increased the levels of acetate esters or ethyl esters, depending on the inoculation method applied. In particular, acetate esters like isobutyl acetate, hexyl acetate, and 2-phenylethyl acetate, which all impart fruity or floral aromas, were significantly increased in SQL. On the other hand, higher levels of total ethyl esters were associated with SML. The most striking differences were observed in the levels of fruit-impair esters like ethyl decanoate, 3-methylbutyl octanoate, and isoamyl hexanoate. This is the first study to report a significant increase in the ethyl ester fraction by L. thermotolerans. Interestingly, L. thermotolerans in SQL also increased the concentrations of damascenone and geraniol, the major teprenic compound of Moschofilero, which are associated with several typical floral and fruity aromas of the variety. Present results show that L. thermotolerans may enhance the varietal character and increase the chemical complexity of Moschofilero wines.

A current trend in winemaking has highlighted the beneficial contribution of non- Saccharomyces yeasts to wine quality. Hanseniaspora uvarum is one of the more represented non- Saccharomyces species onto grape berries and plays a critical role in influencing the wine sensory profile, in terms of complexity and organoleptic richness. In this work, we analyzed a group of H. uvarum indigenous wine strains as for genetic as for technological traits, such as resistance to SO2 and β-glucosidase activity. Three strains were selected for genome sequencing, assembly and comparative genomic analyses at species and genus level. Hanseniaspora genomes appeared compact and contained a moderate number of genes, while rarefaction analyses suggested an open accessory genome, reflecting a rather incomplete representation of the Hanseniaspora gene pool in the currently available genomes. The analyses of patterns of functional annotation in the three indigenous H. uvarum strains showed distinct enrichment for several PFAM protein domains. In particular, for certain traits, such as flocculation related protein domains, the genetic prediction correlated well with relative flocculation phenotypes at lab-scale. This feature, together with the enrichment for oligo-peptide transport and lipid and amino acid metabolism domains, reveals a promising potential of these indigenous strains to be applied in fermentation processes and modulation of wine flavor and aroma. This study also contributes to increasing the catalog of publicly available genomes from H. uvarum strains isolated from natural grape samples and provides a good roadmap for unraveling the biodiversity and the biotechnological potential of these non- Saccharomyces yeasts. [ABSTRACT FROM AUTHOR]

Hanseniaspora , a predominant yeast genus of grape musts, includes sister species recently reported as fast evolving. The aim of this study was to investigate the genetic relationships between the four most closely related species, at the population level. A multi-locus sequence typing strategy based on five markers was applied on 107 strains, confirming the clear delineation of species H. uvarum, H. opuntiae, H. guilliermondii , and H. pseudoguilliermondii. Huge variations were observed in the level of intraspecific nucleotide diversity, and differences in heterozygosity between species indicate different life styles. No clear population structure was detected based on geographical or substrate origins. Instead, H. guilliermondii strains clustered into two distinct groups, which may reflect a recent step toward speciation. Interspecific hybrids were detected between H. opuntiae and H. pseudoguilliermondii. Their characterization using flow cytometry, karyotypes and genome sequencing showed different genome structures in different ploidy contexts: allodiploids, allotriploids, and allotetraploids. Subculturing of an allotriploid strain revealed chromosome loss equivalent to one chromosome set, followed by an auto-diploidization event, whereas another auto-diploidized tetraploid showed a segmental duplication. Altogether, these results suggest that Hanseniaspora genomes are not only fast evolving but also highly dynamic. [ABSTRACT FROM AUTHOR]

Volatile organic compounds (VOCs) of antagonistic yeasts are considered as environmental safe fumigants to promote the resistance and quality of strawberry (Fragaria ananassa). By GC‐MS assays, VOCs of Hanseniaspora uvarum (H. uvarum) fumigated strawberry fruit showed increased contents of methyl caproate (5.8%), methyl octanoate (5.1%), and methyl caprylate (10.9%) in postharvest cold storage. Possible mechanisms of H. uvarum VOCs involved in regulations of the defense‐related enzymes and substances in strawberry were investigated during postharvest storage in low temperature and high humidity (2 ± 1°C, RH 90%–95%). Defense‐related enzymes assays indicated H. uvarum VOCs stimulated the accumulation of CAT, SOD, POD, APX, PPO, and PAL and inhibited biosynthesis of MDA in strawberry fruit under storage condition. Moreover, the expression levels of related key enzyme genes, such as CAT, SOD, APX42, PPO, and PAL6, were consistently increased in strawberry fruit after H. uvarum VOCs fumigation. [ABSTRACT FROM AUTHOR]

Multi-starter wine fermentations employing non- Saccharomyces (NS) yeasts are becoming an emerging trend in winemaking. It is therefore important to determine the impacts of different NS strains in the wine phenotype and in particular the aroma outputs in different inoculation schemes and fermentation conditions. Here, two native NS yeasts, Lachancea thermotolerans LtMM7 and Hanseniaspora uvarum HuMM19, were assessed for their ability to improve the quality of Moschofilero, a Greek aromatic white wine. The NS strains were initially examined in laboratory scale fermentations in mixed inoculations with ScMM23, a native Saccharomyces cerevisiae strain. LtMM7 was selected to be further evaluated in pilot scale fermentations. Five different inoculation schemes were considered: single inoculation of ScMM23 (IS), simultaneous inoculation of ScMM23 with HuMM19 (SMH) or LtMM7 (SML), and sequential inoculation of HuMM19 (SQH) or LtMM7 (SQL) followed by ScMM23. At laboratory scale fermentations, the chemical profiles were largely affected by both the NS species and the inoculation scheme applied. The sequential inoculation using HuMM19 produced the most divergent wine phenotype. However, HuMM19 caused significant increases in acetic acid and ethyl acetate levels that impeded its use in pilot scale trials. LtMM7 significantly affected the chemical profiles of wines produced at the winery, especially in the sequential inoculation scheme. Importantly, LtMM7 significantly increased the levels of acetate esters or ethyl esters, depending on the inoculation method applied. In particular, acetate esters like isobutyl acetate, hexyl acetate, and 2-phenylethyl acetate, which all impart fruity or floral aromas, were significantly increased in SQL. On the other hand, higher levels of total ethyl esters were associated with SML. The most striking differences were observed in the levels of fruit-impair esters like ethyl decanoate, 3-methylbutyl octanoate, and isoamyl hexanoate. This is the first study to report a significant increase in the ethyl ester fraction by L. thermotolerans. Interestingly, L. thermotolerans in SQL also increased the concentrations of damascenone and geraniol, the major teprenic compound of Moschofilero, which are associated with several typical floral and fruity aromas of the variety. Present results show that L. thermotolerans may enhance the varietal character and increase the chemical complexity of Moschofilero wines. [ABSTRACT FROM AUTHOR]

The use of multi-species starter cultures is an approach of increasing significance for winemakers in order to improve the general quality and safety of the final product. As first step of the present study, we isolated and characterize two Saccharomyces cerevisiae yeast starter strains, denoted as ITEM 167292 and ITEM 17293, from natural must fermentations of "Negroamaro" grapes. As second step, we studied the interactions during grape must fermentation between these two strains, the Hanseniaspora uvarum strain ITEM 8785 and five autochthonous Oenococcus oeni strains, by microbial counts and by quantifying l -malic acid and ethanol concentrations. The best performing O. oeni strain, namely OT4, was used to create, with the H. uvarum strain ITEM 8785, two mixed starter formulations with the strains ITEM 167292 and ITEM 17293. The three microbial species showed to be compatible and to complete the fermentative processes producing wines denoted by reduced acetic acid concentrations. The performance of the mixed starter formulations were then validated by carrying pilot-scale vinifications. At the best of our knowledge, this report is the first study regarding the utilization of selected H. uvarum / S. cerevisiae / O. oeni autochthonous strains in a simultaneous multi-starter inoculation for the industrial production of regional typical wines. • The first investigation on a non- Saccharomyces/Saccharomyces/Oeni starter culture is proposed. • The compatibility among microbial species during fermentation was assessed. • The mixed starter produced red wine with reduced acetic acid content. • The results presented were validated by pilot-scale vinification trials. • The industrial application of the mixed starter formulation reported is a promising approach. [ABSTRACT FROM AUTHOR]

In recent studies, the yeast species Hanseniaspora uvarum and Lachancea thermotolerans were isolated from the digestive tract of four North American yellowjacket species (Hymenoptera: Vespidae), and attraction of yellowjackets to brewer's yeast, Saccharomyces cerevisiae (all Saccharomycetaceae), growing on fruit powder was demonstrated. We tested the hypothesis that Vespula spp. are attracted to cultures of H. uvarum and L. thermotolerans and their respective volatiles. In field experiments, we found that H. uvarum and L. thermotolerans are attractive to three species of yellowjacket, but only when grown on grape juice‐infused yeast peptone dextrose (YPD) agar. Using gas chromatography‐mass spectrometry, we analyzed the headspace volatiles produced by these yeasts, and field tested an 18‐component yeast synthetic semiochemical blend. This synthetic blend attracted western yellowjackets, Vespula pensylvanica (Saussure), but no other yellowjacket species. Acetic acid or ethanol added to the synthetic blend at biologically relevant doses either had no effect or significantly lowered trap captures. Our results demonstrate that yeast symbionts isolated from the digestive tract of yellowjackets are attractive to their hosts. Further research is needed to identify the volatiles mediating attraction of species other than V. pensylvanica to the yeast cultures. Yellowjackets in the genus Vespula (Hymenoptera: Vespidae) harbor the yeasts Hanseniaspora uvarum and Lachancea thermotolerans (both Saccharomycetaceae) in their digestive tract. Our research demonstrates that yellowjackets are attracted to these yeasts growing on grape juice‐infused agar, and a synthetic blend of 18 volatiles produced by the yeasts is attractive to western yellowjackets, Vespula pensylvanica. The volatiles produced by symbiotic yeasts show potential for use as a yellowjacket trap bait. [ABSTRACT FROM AUTHOR]