non-Saccharomyces Cerevisiae Research Articles

Dynamic changes in microbiota and volatile profiles of Marselan wine by single or pairwise inoculated three indigenous non-Saccharomyces yeasts

The object of this study was to compare the effects of three indigenous non-Saccharomyces cerevisiae strains (Hanseniaspora uvarum, Metschnikowia sinensis and Rhodotorula mucilaginosa) and their paired (co-inoculated) fermentation on the microbial communities and volatile profiles during the fermentation of Marselan wine. Results showed that both monoculture and mixed fermentation with non-Saccharomyces strain can complete alcohol fermentation wherein the alcohol content of indigenous yeast treatments were significantly higher than that of control NSD. A total of 44 aroma compounds were identified in all samples, among which the H + R mixed inoculation showed the highest aroma content (28581±1576.61 μg/L). In particular, the contents of ethyl butyrate (V5), ethyl octanoate (V9), and ethyl decanoate (V11) were significantly high, which could enhance the fresh fruit aroma in Marselan wine. Microbial diversity analysis showed that the diversity of fungi between groups was greater than that of bacteria, and H + R (Hanseniaspora and Rhodotorula) had higher microbial abundance (bacteria 79, fungi 78) than the other groups. Spearman correlation analysis revealed that Fructobacillus, Acinetobacter, and other indigenous microorganisms were positively correlated with volatile substances. In summary, the mixed fermentation of Hanseniaspora and Rhodotorula can be considered an effective strategy for improving the aroma quality of Marselan wine. This study provides new insight and useful references for the role and application of native non-Saccharomyces yeast in wine making.

Germplasm Resource Mining of Fen-Flavor Baijiu Brewing Micro-Organisms and Screening of Important Functional Strains

The exploration of microbial genetic resources for the production of fFen-flavor Baijiu has not only enriched the microbial library for baijiu production but has also laid the foundation for process improvement and strain optimization in baijiu brewing. In this study, a total of 177 fungal isolates were screened, including Saccharomyces cerevisiae, non-Saccharomyces cerevisiae, molds, and some pathogenic bacteria. Among them, Saccharomyces cerevisiae was the most abundant with 119 isolates, playing a major role in the fermentation of baijiu production. A total of 148 bacterial isolates were obtained from the fermentation mash samples, showing greater diversity compared to fungi. Bacillus species were the most abundant, with 94 isolates. Bacillus licheniformis, in particular, can produce a rich enzymatic system and flavor precursors, making it an important contributor to the sensory quality of baijiu. Lactic acid bacteria were the second most abundant, with 16 isolates. Additionally, five pathogenic fungal species were identified, including Candida pelliculosa, Candida lusitaniae, Fusarium oxysporum, Fusarium solani and Talaromyces marneffei. Six pathogenic bacterial species were also isolated, namely Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus xylosus, Moraxella osloensis, Actinomyces meyeri and Stenotrophomonas maltophilia. Finally, two strains of high acetate ethyl ester-producing yeast and lactate-degrading bacteria with good tolerance to temperature, pH, and ethanol concentration were identified as Saccharomyces cerevisiae and Bacillus licheniformis, respectively.

Effect of sequential fermentation with indigenous non-Saccharomyces cerevisiae combinations and Saccharomyces cerevisiae on the chemical composition and aroma compounds evolution of kiwifruit wine

To unlock the potential of indigenous non-Saccharomyces cerevisiae and develop novel starters to enhance the aromatic complexity of kiwifruit wine, Zygosaccharomyces rouxii, Pichia kudriavzevii and Meyerozyma guilliermondii were pairwise combined and then used in sequential fermentation with Saccharomyces cerevisiae. The impact of different starter cultures on the chemical composition and flavor profile of the kiwifruit wines was comprehensively analyzed, and the aroma evolution during alcoholic fermentation was investigated by examining the changes in key volatiles and their loss rates. Compared with Saccharomyces cerevisiae, mixed starter cultures not only improve antioxidant capacity but also increase esters and alcohols yields, presenting intense floral and fruity aromas with high sensory acceptability. The results indicated that sequential inoculation of non-Saccharomyces cerevisiae combination and Saccharomyces cerevisiae promoted the development of volatiles while maintaining the stability of key aroma compounds in the winemaking environment and reducing the aroma loss rates during alcoholic fermentation.

Comparison of volatile compounds and sensory profiles of low-alcohol pear beverages fermented with Saccharomyces cerevisiae and different non-Saccharomyces cerevisiae

This study aimed to assess the impact of Saccharomyces cerevisiae and different non-Saccharomyces cerevisiae (Zygosaccharomyces bailii, Hanseniaspora opuntiae and Zygosaccharomyces rouxii) on the volatile compounds and sensory properties of low-alcohol pear beverages fermented from three varieties of pear juices (Korla, Laiyang and Binzhou). Results showed that all three pear juices were favorable matrices for yeasts growth. Non-Saccharomyces cerevisiae exhibited a higher capacity for acetate ester production compared to Saccharomyces cerevisiae, resulting in a significant enhancement in sensory complexity of the beverages. PCA and sensory analysis demonstrated that pear varieties exerted a stronger influence on the crucial volatile components and aroma characteristics of the fermented beverages compared to the yeast species. CA results showed different yeast strains exhibited suitability for the fermentation of specific pear juice varieties.

Evaluation of the effect of Torulaspora delbrueckii on important volatile compounds in navel orange original brandy using E–nose combined with HS–SPME–GC–MS

Simultaneous inoculation of non-Saccharomyces cerevisiae during the alcoholic fermentation process has been found to be an effective strategy for enhancing wine flavor. This study aimed to investigate the effect of Torulaspora delbrueckii NCUF305.2 on the flavor of navel orange original brandy (NOOB) using E–nose combined with HS–SPME–GC–MS. The results showed a significant increase (p < 0.05) in the sensitivity of NOOB to W5C, W3C, W1S, and W3S sensors by mixed fermentation (MF). Esters in NOOB increased by 4.13%, while higher alcohols increased by 21.93% (p < 0.001), terpenes and others increased by 52.07% and 40.99% (p < 0.01), respectively. Notably, several important volatile compounds with relative odor activity values above 10 showed an increase. Sensory analysis revealed that a more pronounced citrus-like flavor and higher overall appearance scores were found in MF than in pure fermentation (PF). These findings offer valuable theoretical guidance for enhancing the quality of fruit brandies.

Uniform experimental design optimization of liquid fermentation Baijiu mixed fermentation

In this study, corn alcohol fermentation mash was used as raw material, and different microorganisms were added to improve the flavor of liquid fermentation Baijiu. The optimum fermentation conditions of liquid fermentation Baijiu were optimized by uniform experimental design. The optimum fermentation conditions were as follows: Saccharomyces cerevisiae: non-Saccharomyces cerevisiae=3.8:1, yeast inoculation amount was 0.65 g/g, Lactobacillus inoculation amount was 1%, yeast inoculation time was 26.5 h, Lactobacillus inoculation time was 0.5 h, the total acid content was 1.943 g/L, the estimated total acid yield was 2.036 g/L, and the relative deviation was 0.077%. Compared with the three control groups, the total acid yield increased by 27.39%, 12.36% and 19.05% respectively.

Coculturing of non-Saccharomyces cerevisiae and Saccharomyces cerevisiae for improving the aroma quality and antioxidant characteristics of beer with Yuan'an yellow tea

The utilization of mixed cultures of Saccharomyces and non-Saccharomyces cerevisiae strains to improve the quality and aroma complexity of wines has garnered considerable attention as of late. In this study, three non-S. cerevisiae strains exhibiting a strong β-glucosidase production capacity were screened from the yeasts preserved in the laboratory. Subsequently, the physiological characteristics of the strains were evaluated through growth curve analysis as well as alcohol and osmotic pressure tolerance experiments. Finally, the non-S. cerevisiae strain S14 (Torulaspora delbrueckii) was selected and applied to ferment Yuan'an yellow tea beer combined with S. cerevisiae S189. The results showed that the optimal fermentation performance was achieved when S14 was inoculated first, followed by the addition of S189 after 12 h of fermentation, with an S14:S189 ratio of 10:1. Mixed fermentation resulted in a significant increase in the concentration of volatile flavor compounds in beer, particularly terpenes, alcohols, esters, and acids, which exhibited levels of 520.98 μg/L, 5534.28 μg/L, and 1631.80 μg/L, respectively; these values were 299.25%, 32.45%, and 56.57% higher compared to purebred fermentation. Furthermore, mixed fermentation demonstrated an improvement in the antioxidant activity of beer, as evidenced by the increase in the comprehensive evaluation score (CES) from 1.86 to 2.89. Overall, these findings indicated the notable advantage of non-S. cerevisiae strain S14 in fermenting Yuan'an yellow tea beer.

Screening and characterization of indigenous non-Saccharomyces cerevisiae with high enzyme activity for kiwifruit wine production

To explore the diversity and fermentation potential of non-Saccharomyces cerevisiae associated with kiwifruit, indigenous yeasts isolated from kiwifruit and natural fermentation were comprehensively analyzed. A total of 166 indigenous yeasts were isolated, of which 54 representative strains were used for subsequent enzyme activity characterization. Different colorimetric methods were used to verify the ability of these strains to secrete hydrolytic enzymes, and then six strains were selected for sequential fermentation by specific activity assay. The performance of indigenous yeasts in improving organic acids, polyphenols, volatile compounds and sensory characteristics of wines was evaluated holistically. Results indicated that most sequential fermentations exhibited significant improvements in vitamin C and polyphenols. Remarkably, the involvement of Zygosaccharomyces rouxii, Meyerozyma guilliermondii, and Pichia kudriavzevii increased the concentrations of ethyl esters, acetates and alcohols, enhancing floral and tropical fruit odors and ultimately achieving the highest overall sensory acceptability, thereby highlighting their potential in kiwifruit wine fermentation.

Chemical Composition and Flavor Characteristics of Cider Fermented with Saccharomyces cerevisiae and Non-Saccharomyces cerevisiae.

Cider flavor has a very important impact on the quality. Solid-phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS) combined with gas chromatography-ion mobility spectrometry (GC-IMS) tested different kinds of non-Saccharomyces yeasts and Saccharomyces cerevisiae (S. cerevisiae) co-inoculated for the fermentation of cider to determine differences in aroma material, and the determination of odor activity value (OAV) is applied less frequently in research. Through Rhodotorula mucilaginosa, Debaryomyces hansenii, Zygosaccharomyces bailii, and Kluyveromyces Marxianus, four different strains of non-Saccharomyces yeast fermented cider, and it was found that, in both the chemical composition and flavor of material things, compared with monoculture-fermented cider using S. cerevisiae, all differences were significant. Co-inoculated fermentation significantly improved the flavor and taste of cider. As in the volatile compounds of OVA > 1, octanoic acid (Sc 633.88 μg/L, co-inoculation fermented group 955.49 μg/L) provides vegetable cheese fragrance and decanoic acid, ethyl ester (Sc 683.19 μg/L, co-inoculation fermented group 694.98 μg/L) a creamy fruity fragrance, etc., and the average content increased after co-inoculated fermentation. Phenylethyl alcohol, which can produce a rose scent, was relatively abundant in cider samples and varied greatly among the groups. Moreover, the contents of ethyl lactate and 1-butanol in the Sc+Rm (ciders fermented by S. cerevisiae and R. mucilaginosa) were the highest of all of the cider samples. Different types of non-Saccharomyces yeast produced cider with different flavor characteristics. This study demonstrates that different species of non-Saccharomyces yeast do have an important impact on the characteristics of cider and that co-inoculation with non-Saccharomyces yeast and S. cerevisiae for cider fermentation may be a strategy to improve the flavor of cider.

Sequential fermentation with indigenous non-Saccharomyces yeasts and Saccharomyces cerevisiae for flavor and quality enhancement of Longyan dry white wine

In this study, we investigated the effect of the sequential fermentation of four selected indigenous non-Saccharomyces yeasts (Candida stellimalicola HL-S-5, Rhodotorula mucilaginosa HL-S-8, Hanseniaspora uvarum HL-S-9, and Pichia kluyveri XL-48-6) and Saccharomyces cerevisiae VL2 on the oenological parameters, volatile compositions, organic acids, and sensory characteristics of Longyan dry white wine. Results showed that the ethanol concentration of pure fermentation (11.12 ± 0.04%, v/v) was the highest among all fermentations. Furthermore, the aroma concentrations produced by the fermentation of R. mucilaginosa HL-S-8/VL2 (9929.35 ± 96.87 μg/L) and P. kluyveri XL-48-6/VL2 (9017.67 ± 85.91 μg/L) were significantly higher than that of VL2 (7654.64 ± 397.07 μg/L). In particular, the treatment of R. mucilaginosa HL-S-8/VL2 increased the content of acetic esters (512.11 ± 12.92 μg/L) and fatty acid ethyl esters (6893.64 ± 56.67 μg/L), which enhanced fruity and floral characteristics. The sequential fermentation of R. mucilaginosa HL-S-8/VL2 led to significantly higher organic acid content (3843.32 ± 73.93 mg/L) than the other samples. Moreover, the sequential fermentation of R. mucilaginosa HL-S-8/VL2 wine samples resulted in the highest scores in sensory evaluation. Therefore, the sequential fermentation of R. mucilaginosa HL-S-8/VL2 was an effective way to improve wine flavor and quality. This work will provide a useful reference for improving the flavor and quality of Longyan wine through non-Saccharomyces cerevisiae.

Isolation, Identification, and Characterization of an Acid-Tolerant Pichia kudriavzevii and Exploration of Its Acetic Acid Tolerance Mechanism

Pichia kudriavzevii is one of the major non-Saccharomyces cerevisiae yeasts in Chinese baijiu brewing, which has shown a substantially higher tolerance to acid, heat, and ethanol. Exploring the mechanism of P. kudriavzevii could have a positive effect on the artificially controlled production of baijiu. In this study, an efficient acetic-acid-tolerant P. kudriavzevii strain, Y2, was isolated from the yellow water of strong-flavored baijiu brewing waste, and its molecular mechanism of acetic acid tolerance was investigated through a comparative transcriptomic analysis. The strain Y2 could tolerate 12 g/L of acetic acid. According to the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis, differentially expressed genes (DEGs) were mainly enriched in oxidative phosphorylation, the citrate cycle, glycolysis/gluconeogenesis, and carbon metabolism under low (AL group) and high (AH group) concentrations of acetic acid. However, the DEG enrichment was more profound in the AH group when compared to the control. Compared with the AL group, the expression of genes related to oxidative phosphorylation was more significantly upregulated, while in terms of the TCA cycle, phosphoenolpyruvate carboxykinase was significantly upregulated in both the AH and AL groups and was positively correlated with tolerance to acetic acid. This was followed by citrate synthase, isocitrate dehydrogenase, malate dehydrogenase, and succinate dehydrogenase. These results illustrated a possible mechanism of acid tolerance by regulating the metabolism-related pathways in P. kudriavzevii and provided a basis for the further investigation of the acid tolerance mechanism.

Adjustment of impact phenolic compounds, antioxidant activity and aroma profile in Cabernet Sauvignon wine by mixed fermentation of Pichia kudriavzevii and Saccharomyces cerevisiae.

Mixed fermentation using saccharomyces cerevisiae and non-saccharomyces cerevisiae has become one of the main research strategies to improve wine aroma. Hence, this study applied the mixed fermentation technique using Pichia kudriavzevii and Saccharomyces cerevisiae to brew Cabernet Sauvignon wine and to investigate the effects of inoculation timing and inoculation ratio on the polyphenolics, antioxidant activity and aroma of the resulting wine. The results showed that mixed fermentation significantly improved the amounts of flavan-3-ols. In particular, S1:5 had the highest amounts of (-)-catechin and procyanidin B1 (73.23mg/L and 46.59mg/L), while S1:10 had the highest (-)-epicatechin content (57.95mg/L). Meanwhile, S1:10 showed the strongest FRAP, CUPRAC and ABTS+activities (31.46 %, 25.38 % and 13.87 % higher than that of CK, respectively). In addition, mixed fermentation also increased the amounts of phenylethanol, isoamyl alcohol and ethyl esters, which enhanced the rose-like and fruity flavor of wine. This work used a friendly non-saccharomyces cerevisiae alongside appropriate inoculation strategies to provide an alternative approach for improved wine aroma and phenolic profile.

Indigenous yeast can increase the phenolic acid and volatile ester compounds in Petit Manseng wine.

Indigenous yeasts are generally found in grapes, vineyards, and natural environments. Sequential inoculation and fermentation with non-Saccharomyces cerevisiae yeast (H30) and Saccharomyces cerevisiae (YT13) also improve the flavor of wine. This study sequentially inoculated fermented Petit Manseng and natural grape juice with native H30 and YT13 selected from vineyards in Yantai, China. The sensory characteristics of Petit Manseng wine were evaluated by detecting the primary organic acids, phenolic acid compounds, and volatile ester compounds. The results showed that the lactic acid content of the natural wine fermented sequentially with H30 and YT13 increased by 490 μg/L compared with the control group, while the ferulic acid content was 1.4 times that of the single-yeast fermentation group. Furthermore, butyrolactone and anthocyanidin propionate were present in the mixed fermentation group, increasing the aroma complexity of Petit Manseng wine and providing high-quality yeast resources that increase the regional characteristics when producing dry white wine.

Effect of Hanseniaspora uvarum-Saccharomyces cerevisiae Mixed Fermentation on Aroma Characteristics of Rosa roxburghii Tratt, Blueberry, and Plum Wines.

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.

The Impact of Indigenous Non-Saccharomyces Yeasts Inoculated Fermentations on ‘Semillon’ Icewine

The emerging low acidity in icewine grapes is becoming a major problem in producing quality icewine. Using non-Saccharomyces cerevisiae yeasts in fermentation can improve wine’s organoleptic characteristics and aromatic quality. This study evaluated two indigenous non-Saccharomyces cerevisiae yeasts, Lachancea thermotolerans (LT-2) and Torulaspora delbrueckii (TD-3), for their ability to improve the acidity and quality of ‘Semillon’ icewine. Five different inoculation schemes were implemented, including a single inoculation of S. cerevisiae (SC), L. thermotolerans (LT), and T. delbrueckii (TD); the sequential inoculation of L. thermotolerans, followed by S. cerevisiae after 6 days (L-S); and the sequential inoculation of L. thermotolerans, followed by T. delbrueckii after 6 days (L-D). The results showed that, during sequential fermentation (L-S and L-D), the presence of S. cerevisiae or T. delbrueckii slightly restrained the growth of L. thermotolerans. Single or sequential inoculation with L. thermotolerans and T. delbrueckii significantly reduced the amount of volatile acidity and increased the glycerol content. Furthermore, fermentations involving L. thermotolerans produced relevant amounts of lactic acid (2.04–2.2 g/L) without excessive deacidification of the icewines. Additionally, sequential fermentations increased the concentration of terpenes, C13-norisoprenoid compounds, and phenethyl compounds. A sensory analysis also revealed that sequentially fermented icewines (L-S and L-D) had more fruity and floral odors and aroma intensity. This study highlights the potential application of L. thermotolerans and T. delbrueckii in sequential fermentation to improve the icewine quality.

전통누룩에서 분리한 non-Saccharomyces cerevisiae의 이화학적 및 기능적 특성

This study was conducted to evaluate the alcohol-producing abilities and functional characteristics of five strains of non-Saccharomyces cerevisiae (NSC), namely, Kluyveromyces marxianus KJ-L, Wickerhamomyces anomalus KJ-1, W. anomalus CP-2, Pichia anomalus HAN-1, and Meyerozyma guilliermondii SU-L, which were isolated from Korean traditional nuruk. The selected yeast strains produced large amounts of alcohol using a carbon source of 20% glucose and were identified as NSC based on their 18S rDNA sequences. The optimal growth temperature and pH of the NSC except for M. guilliermondii SU-L were 25°C and 4.0, respectively. Two NSC strains, KJ-L and CP-2, produced 5–10% more alcohol compared to that produced by S. cerevisiae LP (SC LP) control. Although the α-amylase and ß-glucosidase activities were slightly lower in the NSC strains than in the SC LP, glucoamylase activity was 1.4-fold higher in the NSC strains than in the SC LP. The α-glucosidase inhibition activity evaluated using 1% acarbose was 29-fold higher for K. marxianus KJ-L and P. anomalus HAN-1 than that of SC LP. The five strains of NSC exhibited higher angiotensin-converting enzyme inhibitory activity with inhibition rates of 51.7–61.7% compared to that of SC LP (37.3%). The tyrosinase inhibition activities of NSC (86.4-91.5%) and SC LP (94.9%) were significantly higher than that of the positive control, kojic acid. These NSC yeast show high potential for industrial application as domestic starters for manufacturing fermented foods and cosmetics based on their physiological activities and functional characteristics.

Effect of sequential fermentation with four non-Saccharomyces and Saccharomyces cerevisiae on nutritional characteristics and flavor profiles of kiwi wines

To improve the functional properties and flavor complexity of kiwi wine using different non-Saccharomyces cerevisiae, Wickeramomyces anomala (Wa), Zygosaccharomyces rouxii (Zr), ZygoSaccharomyces bailii (Zb) and Schizosaccharomyces pombe (Sp) were inoculated sequentially with S. cerevisiae (Sc). The physicochemical and sensorial profiles of the wines were evaluated. The evolution of cells showed that non-Saccharomyces exhibited varying degrees of fermentation vigor and only acted during the first vinification stage. Ethanol content, pH, ΔE and organic acids in the wines varied according to the yeasts used. Compared with the pure Sc fermentation, the sequential fermentations of Wa-Sc and Sp-Sc significantly increased the production of polyphenols. Fifteen volatile compounds with relative odor activity values (rOAV) ≥ 1.0 were identified. Furthermore, principal component analysis (PCA) revealed that Zr-Sc and Sp-Sc were correlated with higher levels of ethyl esters (ethyl hexanoate, ethyl heptanoate, ethyl decanoate), isoamyl acetate and 2-phenyl-1-ethanol in the wines, improving the flower and sweet notes. Zr-Sc also enhanced the tropical fruity aroma. Sequential inoculation with Zb was related to the contents of acetate esters, ethyl butyrate, methyl butyrate and cineole, triggering the tropical fruity odor. In addition, the partial least-squares regression (PLSR) revealed that acetate esters contributed greatly to the tropical fruity note.

The N.C.Yeastract and CommunityYeastract databases to study gene and genomic transcription regulation in non-conventional yeasts.

Responding to the recent interest of the yeast research community in non-Saccharomyces cerevisiae species of biotechnological relevance, the N.C.Yeastract (http://yeastract-plus.org/ncyeastract/) was associated to YEASTRACT + (http://yeastract-plus.org/). The YEASTRACT + portal is a curated repository of known regulatory associations between transcription factors (TFs) and target genes in yeasts. N.C.Yeastract gathers all published regulatory associations and TF-binding sites for Komagataellaphaffii (formerly Pichia pastoris), the oleaginous yeast Yarrowia lipolytica, the lactose fermenting species Kluyveromyces lactis and Kluyveromyces marxianus, and the remarkably weak acid-tolerant food spoilage yeast Zygosaccharomyces bailii. The objective of this review paper is to advertise the update of the existing information since the release of N.C.Yeastract in 2019, and to raise awareness in the community about its potential to help the day-to-day work on these species, exploring all the information available in the global YEASTRACT + portal. Using simple and widely used examples, a guided exploitation is offered for several tools: (i) inference of orthologous genes; (ii) search for putative TF binding sites and (iii) inter-species comparison of transcription regulatory networks and prediction of TF-regulated networks based on documented regulatory associations available in YEASTRACT + for well-studied species. The usage potentialities of the new CommunityYeastract platform by the yeast community are also discussed.

Characterization of different non-Saccharomyces yeasts via mono-fermentation to produce polyphenol-enriched and fragrant kiwi wine

To improve the functional property and flavor quality of kiwi wine, the performance of 11 strains of non-Saccharomyces yeasts from 5 species were comprehensively characterized in kiwi wine. Chemical compositions and sensorial profiles of all kiwi wines were assessed. The results indicated that most non-Saccharomyces cerevisiae produced more polyphenols than Saccharomyces cerevisiae WLS21 (Sc21). A total of 130 volatiles were observed in the kiwi wines. Zygosaccharomyces rouxii IFO30 (Zr30), Zygosaccharomyces bailii IFO37 (Zb37) and Schizosaccharomyces pombe 1757 (Sp57) were found to produce more concentration of volatile compounds than the other strains including Sc21. 25 volatiles with a rOAV ≥0.1 were identified. Principal component analysis (PCA) revealed that Zr30 and Zb37 specifically increased the concentrations of ethyl esters, 2-methylbutan-1-ol and phenethyl acetate, while Sp57 primarily enhanced the contents of phenylacetaldehyde, 2-methylbutan-1-ol and phenethyl acetate. The sensory analysis demonstrated that Zr30 and Zb37 strains were more optimal than S. cerevisiae in aroma generation. In addition, the partial least-squares regression (PLSR) analysis revealed that tropical fruits, red fruits, dried fruits, flowers and floral odors showed an intensely positive impact on the overall acceptability of the kiwi wine.

Effects of Honey Variety and Non-Saccharomyces cerevisiae on the Flavor Volatiles of Mead

This study examined the effects of honey varieties and non-Saccharomyces cerevisiae (Torulaspora delbrueckii and Kluyveromyces thermotolerans) on the flavor volatiles of mead. Five different types of mead were prepared from the honey varieties: vitex, acacia, linden, multifloral, and jujube. Among them, multifloral mead had the highest alcohol content, and acacia mead had the highest ester and acid content. As for the effect of non-Saccharomyces yeasts, vitex mead fermented with EC1118 exhibited the highest volatile-compound content, T. delbrueckii had the highest alcohol content (especially isopentanol and α-phenylethyl alcohol), and K. thermotolerans had the highest ethyl acetate and n-decanoic acid content. EC1118 had different effects on the flavor-volatile content of the two non-Saccharomyces cerevisiae fermented meads. Moreover, principal component analysis (PCA) and sensory analysis revealed considerable differences among the aroma components of the mead, which confirmed major differences among the aroma substances detected in this study.