-
Fungal Biology Jun 2023Yeast complexes in the composting process of cow dung prepared to fertilize the soil for growing vegetables and fruits were studied. The average abundance of yeasts...
Yeast complexes in the composting process of cow dung prepared to fertilize the soil for growing vegetables and fruits were studied. The average abundance of yeasts changed during the four temperature stages of the composting process. The highest abundance of yeasts, 1.38 × 10 cfu/g, was observed in the second stage of heating from 20 to 40 °C; the lowest was studied in the stage with the highest temperature (65 °C), 1.68 × 10 cfu/g. A total of 19 yeast species were observed and identified: 11 ascomycetes and 8 basidiomycetes, belonging to five subphyla of Fungi: Saccharomycotina (10), Pezizomycotina (1), Agaricomycotina (5), Pucciniomycotina (2), and Ustilaginomycotina (1). The greatest diversity of yeasts was found in the initial (20 °C) and second (heating up to 40 °C) temperature stages of composting (Aureobasidium pullulans (yeast-like fungus), Candida parapsilosis, Candida saitoana, Candida santamariae, Candida tropicalis, Curvibasidium cygneicollum, Cutaneotrichosporon moniliforme, Debaryomyces fabryi, Debaryomyces hansenii, Filobasidium magnum, Kazachstania sp., Moesziomyces bullatus, Naganishia globosa, Papiliotrema flavescens, Rhodotorula mucilaginosa, Scheffersomyces insectosa, Torulaspora delbrueckii, Vanrija musci), and the lowest in the stage of maximum heating (65 °C) (C. parapsilosis, C. tropicalis, Cyberlindnera jadinii).The opportunistic yeasts C. parapsilosis and C. tropicalis were obtained not only in the initial, second and third temperature stages of the composting process, but also in mature compost in the final stage prepared for soil application. This study shows that the cow dung, used in the farm studied did not meet the microbiological safety criteria. The reduction of opportunistic yeast species was not achieved with the composting method used. The likelihood of these species entering agricultural products via compost and soil and developing as endophytes in the internal tissues of fruits is very high. Since some strains of opportunistic Candida species from cow dung exhibited virulent characteristics (they produced hydrolytic enzymes and were resistant to antifungal compounds), additional phenotypic and genetic studies of the compost strains and their comparison with clinical isolates should be pursued.
Topics: Animals; Cattle; Composting; Yeasts; Candida; Fungi; Soil
PubMed: 37344009
DOI: 10.1016/j.funbio.2023.06.001 -
Frontiers in Microbiology 2020is a yeast species typically present in the early stages of the fermentation process. positively modifies the aromatic properties of wines. However, its contribution...
is a yeast species typically present in the early stages of the fermentation process. positively modifies the aromatic properties of wines. However, its contribution to the final quality of the wine is restricted by its low tolerance to ethanol. is capable of fermenting and tolerating an ethanol concentration ranging from 7.4% (v/v) to slightly higher than 9% (v/v). For this reason, it cannot complete fermentation, when alcohol reach levels higher than 12% (v/v), limiting their use in the industry. The objective of this work was to obtain new variants of with improved resistance to ethanol through adaptive laboratory evolution. Variants capable of tolerating ethanol levels of 11.5% (v/v) were obtained. These presented improved kinetic parameters, and additionally showed an increase in resistance to SO in ethanol compared to the original strain. Co-inoculated fermentations were performed with the original strain (FTd/Sc) and with the evolved strain (FTdF/Sc), in addition to a control fermentation using only EC1118 (FSc). The results obtained show that FTdF/Sc present higher levels of 2-Ethylhexanol, compared to FTd/Sc and FSc. Furthermore, FTdF/Sc presents higher levels of total alcohols, total aldehydes, total phenolic derivatives, and total sulfur compounds with significant differences with FSc. These results provide a YCPUC10-F yeast with higher resistance to ethanol, which can be present throughout the fermentation process and be used in co-inoculated fermentations. This would positively impact the performance of by allowing it to be present not only in the early stages of fermentation but to remain until the end of fermentation.
PubMed: 33408704
DOI: 10.3389/fmicb.2020.595023 -
Food Research International (Ottawa,... Jun 2022Salted soy whey, a liquid by-product from salted tofu processing, is a source of valuable nutrients. However, it is often under-utilized due to its high salt content....
Exploring the feasibility of biotransforming salted soy whey into a soy sauce-like condiment using wine yeast Torulaspora delbrueckii and soy sauce yeasts Zygosaccharomyces rouxii and Candida versatilis as single starter cultures.
Salted soy whey, a liquid by-product from salted tofu processing, is a source of valuable nutrients. However, it is often under-utilized due to its high salt content. The objective of this study was to investigate the feasibility of using different species of yeast to transform salted soy whey into a soy sauce-like condiment. Three yeasts were used for salted soy whey biotransformation: Zygosaccharomyces rouxii NCYC 1682, Candida versatilis NCYC 1433, and Torulaspora delbrueckii Biodiva. This study focused on the growth of the yeasts in soy whey added with different levels of NaCl and the physicochemical changes of salted soy whey after fermentation. The soy sauce yeasts (Z. rouxii and C. versatilis) grew by approximately 2 log CFU/mL in soy whey with 2% and 10% salt while the cell count of wine yeast T. delbrueckii increased by around 1.5 log CFU/mL at 10% salt and 1.78 log CFU/mL at 2% salt after 14 days of fermentation. Candida versatilis grew better at 10% salt with less glucose consumption (consumed 68.49% at 10% versus 94.05% at 2% salt) than at 2% salt. It was also found that all three yeasts converted isoflavone glycosides (bound isoflavones) into aglycones (free isoflavones), the latter having better bioavailability. C. versatilis showed the greatest ability to transform isoflavone glycosides in salted soy whey into higher amounts of aglycones (conversion efficiency of 23.04% at 2% salt and 15.05% at 10% salt). Salted soy whey fermented with different yeasts had different volatile profiles. Soy sauce yeasts produced more isobutyl alcohol, isoamyl alcohol and volatile phenols while T. delbrueckii generated a substantial amount of ethanol and esters. This study revealed the growth and flavour modulating potential of yeasts in salted soy whey fermentation, which provides a possible avenue to develop a soy sauce-like condiment using salted soy whey as a substrate.
Topics: Condiments; Feasibility Studies; Glycosides; Isoflavones; Saccharomyces cerevisiae; Saccharomycetales; Sodium Chloride; Soy Foods; Torulaspora; Whey; Whey Proteins; Wine
PubMed: 35650979
DOI: 10.1016/j.foodres.2022.111350 -
Journal of Dairy Science Dec 2023The possible contribution of brine-derived microflora to the sensory attributes of cheese is still a rather unexplored field. In this study, 365 bacteria and 105 yeast...
The possible contribution of brine-derived microflora to the sensory attributes of cheese is still a rather unexplored field. In this study, 365 bacteria and 105 yeast strains isolated from 11 cheese brines were qualitatively tested for proteolytic and lipolytic activities, and positive strains were identified by sequencing. Among bacteria, Staphylococcus equorum was the most frequent, followed by Macrococcus caseolyticus and Corynebacterium flavescens. As for yeasts, Debaryomyces hansenii, Clavispora lusitaniae, and Torulaspora delbrueckii were most frequently identified. A total of 38% of bacteria and 59% of yeasts showed at least 1 of the metabolic activities tested, with lipolytic activity being the most widespread (81% of bacteria and 95% of yeasts). Subsequently 15 strains of bacteria and 10 yeasts were inoculated in a curd-based medium and assessed via headspace-solid phase microextraction coupled with gas chromatography-mass spectrometry to determine their volatilome. After a 30-d incubation at 12°C, most strains showed a viability increase of about 2 log cfu/mL, suggesting good adaptability to the cheese environment. A total of 26 compounds were detected in the headspace, carbonyl compounds and alcohols being the major contributors to the volatile profile of the curd-based medium. Multivariate analysis was carried out to elucidate the overall differences in volatiles produced by selected strains. Principal component analysis and hierarchical clustering analysis demonstrated that the brine-related microorganisms were separated into 3 different groups, suggesting their different abilities to produce volatile compounds. Some of the selected strains have been shown to have interesting aromatic potential and to possibly contribute to the sensory properties of cheese.
Topics: Animals; Salts; Yeasts; Bacteria; Gas Chromatography-Mass Spectrometry; Cheese
PubMed: 37641243
DOI: 10.3168/jds.2022-23051 -
FEMS Yeast Research Aug 2022Recently, non-Saccharomyces yeast have become very popular in wine and beer fermentation. Their interesting abilities introduce novel aromatic profiles to the fermented...
Recently, non-Saccharomyces yeast have become very popular in wine and beer fermentation. Their interesting abilities introduce novel aromatic profiles to the fermented product. In this study, screening of eight non-Saccharomyces yeast (Starmerella bombicola, Lindnera saturnus, Lindnera jadinii, Zygosaccharomyces rouxii, Torulaspora delbrueckii, Pichia kluyveri, Candida pulcherrima, and Saccharomycodes ludwigii) revealed their potential in non-alcoholic beer production. Conditions for non-alcoholic beer production were optimised for all strains tested (except T. delbrueckii) with the best results obtained at temperature 10 to 15 °C for maximum of 10 days. Starmerella bombicola, an important industrial producer of biosurfactants, was used for beer production for the first time and was able to produce non-alcoholic beer even at 20°C after 10 days of fermentation. Aromatic profile of the beer fermented with S. bombicola was neutral with no negative impact on organoleptic properties of the beer. The most interesting organoleptic properties were evaluated in beers fermented with L. jadinii and L. saturnus, which produced banana-flavoured beers with low alcohol content. This work confirmed the suitability of mentioned yeast to produce non-alcoholic beers and could serve as a steppingstone for further investigation.
Topics: Beer; Fermentation; Saccharomycetales; Torulaspora; Wine
PubMed: 35918186
DOI: 10.1093/femsyr/foac039 -
Molecules (Basel, Switzerland) Jan 2021Wine fermentation processes are driven by complex microbial systems, which comprise eukaryotic and prokaryotic microorganisms that participate in several biochemical... (Review)
Review
Wine fermentation processes are driven by complex microbial systems, which comprise eukaryotic and prokaryotic microorganisms that participate in several biochemical interactions with the must and wine chemicals and modulate the organoleptic properties of wine. Among these, yeasts play a fundamental role, since they carry out the alcoholic fermentation (AF), converting sugars to ethanol and CO together with a wide range of volatile organic compounds. The contribution of , the reference organism associated with AF, has been extensively studied. However, in the last decade, selected strains received considerable commercial and oenological interest due to their specific pro-technological aptitudes and the positive influence on sensory quality. This review aims to highlight the inter-specific variability within the heterogeneous class of non- in terms of synthesis and release of volatile organic compounds during controlled AF in wine. In particular, we reported findings on the presence of model non- organisms, including spp. and , in combination with . The evidence is discussed from both basic and applicative scientific perspective. In particular, the oenological significance in different kind of wines has been underlined.
Topics: Fermentation; Hanseniaspora; Metschnikowia; Odorants; Pichia; Saccharomycetales; Torulaspora; Volatile Organic Compounds; Wine
PubMed: 33530641
DOI: 10.3390/molecules26030644 -
International Journal of Molecular... Jan 2021The surfaces of grapes are covered by different yeast species that are important in the first stages of the fermentation process. In recent years, non- yeasts such as ,... (Review)
Review
The surfaces of grapes are covered by different yeast species that are important in the first stages of the fermentation process. In recent years, non- yeasts such as , , , and have become popular with regard to winemaking and improved wine quality. For that reason, several manufacturers started to offer commercially available strains of these non- species. stands out, mainly due to its contribution to wine aroma, glycerol, ethanol yield, and killer factor. The metabolism of the yeast allows it to increase volatile molecules such as esters and varietal thiols (aroma-active compounds), which increase the quality of specific varietal wines or neutral ones. It is considered a low- or non-fermentative yeast, so subsequent inoculation of a more fermentative yeast such as is indispensable to achieve a proper fermented alcohol. The impact of is not limited to the grape wine industry; it has also been successfully employed in beer, cider, durian, and tequila fermentation, among others, acting as a promising tool in those fermentation processes. Although no species other than is available in the regular market, several recent scientific studies show interesting improvements in some wine quality parameters such as aroma, polysaccharides, acid management, and color stability. This could motivate yeast manufacturers to develop products based on those species in the near future.
Topics: Bioengineering; Ecology; Fermentation; Food Quality; Industrial Microbiology; Pichia; Vitis; Wine
PubMed: 33530422
DOI: 10.3390/ijms22031196 -
Food Chemistry Feb 2022Black currants (Ribes nigrum) were fermented with Saccharomyces and non-Saccharomyces yeasts without added sugar to yield low-ethanol-content beverages. The effects of...
Comparison of volatile compounds and sensory profiles of alcoholic black currant (Ribes nigrum) beverages produced with Saccharomyces, Torulaspora, and Metschnikowia yeasts.
Black currants (Ribes nigrum) were fermented with Saccharomyces and non-Saccharomyces yeasts without added sugar to yield low-ethanol-content beverages. The effects of yeasts on the volatile compounds and sensory characteristics were analysed by HS-SPME-GC-MS, GC-O, and generic descriptive analysis. Ninety-eight volatile compounds were identified from the black currant juice and fermented beverages. Significant increases in the contents of esters (131 %), higher alcohols (391 %), and fatty acids (not present in juice sample) compared to initial juice were observed depending on the yeasts used. GC-O analysis revealed the higher impact of esters on the sensory properties of Saccharomyces bayanus-fermented beverage compared to the Torulaspora delbrueckii-fermented beverage. In the sensory evaluation, non-Saccharomyces yeasts resulted in a higher 'black currant odour'. However, all beverages were intensely sour, which can be a significant challenge in the development of alcoholic berry beverages.
Topics: Alcoholic Beverages; Fermentation; Metschnikowia; Ribes; Saccharomyces; Torulaspora; Wine; Yeasts
PubMed: 34520974
DOI: 10.1016/j.foodchem.2021.131049 -
International Journal of Molecular... Dec 2021The killer phenotype of (Td) and (Sc) is encoded in the genome of medium-size dsRNA viruses (V-M). Killer strains also contain a helper large size (4.6 kb) dsRNA virus...
The killer phenotype of (Td) and (Sc) is encoded in the genome of medium-size dsRNA viruses (V-M). Killer strains also contain a helper large size (4.6 kb) dsRNA virus (V-LA) which is required for maintenance and replication of V-M. Another large-size (4.6 kb) dsRNA virus (V-LBC), without known helper activity to date, may join V-LA and V-M in the same yeast. Kbarr1 killer strain contains the killer virus Mbarr1 in addition to two L viruses, TdV-LAbarr1 and TdV-LBCbarr1. In contrast, the Kbarr2 killer strain contains two M killer viruses (Mbarr1 and M1) and a LBC virus (TdV-LBCbarr2), which has helper capability to maintain both M viruses. The genomes of TdV-LBCbarr1 and TdV-LBCbarr2 were characterized by high-throughput sequencing (HTS). Both RNA genomes share sequence identity and similar organization with their ScV-LBC counterparts. They contain all conserved motifs required for translation, packaging, and replication of viral RNA. Their Gag-Pol amino-acid sequences also contain the features required for cap-snatching and RNA polymerase activity. However, some of these motifs and features are similar to those of LA viruses, which may explain that at least TdV-LBCbarr2 has a helper ability to maintain M killer viruses. Newly sequenced ScV-LBC genomes contained the same motifs and features previously found in LBC viruses, with the same genome location and secondary structure. Sequence comparison showed that LBC viruses belong to two clusters related to each species of yeast. No evidence for associated co-evolution of specific LBC with specific M virus was found. The presence of the same M1 virus in and raises the possibility of cross-species transmission of M viruses.
Topics: Amino Acid Sequence; Base Sequence; Capsid; Double Stranded RNA Viruses; Genome, Viral; Helper Viruses; RNA, Double-Stranded; RNA, Viral; Saccharomyces cerevisiae; Torulaspora; Wine
PubMed: 34948288
DOI: 10.3390/ijms222413492 -
Food Research International (Ottawa,... Nov 2020Nitrogen content of grape musts strongly impacts on fermentation performance and wine metabolite production. As nitrogen is a limiting nutrient in most grape musts,...
Phenotypic and transcriptional analysis of Saccharomyces cerevisiae during wine fermentation in response to nitrogen nutrition and co-inoculation with Torulaspora delbrueckii.
Nitrogen content of grape musts strongly impacts on fermentation performance and wine metabolite production. As nitrogen is a limiting nutrient in most grape musts, nitrogen supplementation is a common practice that ensures yeast growth during fermentation. However, preferred nitrogen sources -as ammonium- repress the genes related to alternative nitrogen sources consumption, usually involved in aromatic compounds production. Here, we describe the effect of high ammonium doses in Saccharomyces cerevisiae fermentation performance and wine properties, and how it is affected by yeast co-inoculation in mixed (S. cerevisiae + Torulaspora delbrueckii) fermentations. In addition, an RNA-seq analysis allowed us to study the S. cerevisiae transcriptional response to ammonium nutrition and yeast interaction, demonstrating that T. delbrueckii presence affects the global S. cerevisiae transcriptional response, reducing ammonium effects at both phenotypic -fermentation kinetics and metabolite production- and transcriptional levels, under experimental conditions.
Topics: Fermentation; Nitrogen; Saccharomyces cerevisiae; Torulaspora; Wine
PubMed: 33233242
DOI: 10.1016/j.foodres.2020.109663