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Food Microbiology Jun 2023The use of Torulaspora delbrueckii in the alcoholic fermentation (AF) of grape must is increasingly studied and used in the wine industry. In addition to the...
The use of Torulaspora delbrueckii in the alcoholic fermentation (AF) of grape must is increasingly studied and used in the wine industry. In addition to the organoleptic improvement of wines, the synergy of this yeast species with the lactic acid bacterium Oenococcus oeni is an interesting field of study. In this work, 60 strain combinations were compared: 3 strains of Saccharomyces cerevisiae (Sc) and 4 strains of Torulaspora delbrueckii (Td) in sequential AF, and four strains of O. oeni (Oo) in malolactic fermentation (MLF). The objective was to describe the positive or negative relationships of these strains with the aim of finding the combination that ensures better MLF performance. In addition, a new synthetic grape must has been developed that allows the success of AF and subsequent MLF. Under these conditions, the Sc-K1 strain would be unsuitable for carrying out MLF unless there is prior inoculation with Td-Prelude, Td-Viniferm or Td-Zymaflore always with the Oo-VP41 combination. However, from all the trials performed, it appears that the combinations of sequential AF with Td-Prelude and Sc-QA23 or Sc-CLOS, followed by MLF with Oo-VP41, reflected a positive effect of T. delbrueckii compared to inoculation of Sc alone, such as a reduction in L-malic consumption time. In conclusion, the obtained results highlight the relevance of strain selection and yeast-LAB strain compatibility in wine fermentations. The study also reveals the positive effect on MLF of some T. delbrueckii strains.
Topics: Saccharomyces cerevisiae; Torulaspora; Fermentation; Wine; Vitis; Oenococcus; Malates
PubMed: 36906299
DOI: 10.1016/j.fm.2022.104212 -
Frontiers in Microbiology 2022Canastra cheese is the most well-known artisanal cheese produced in Brazil. Although its production includes a step to remove fungi from the cheese surface, in recent...
Canastra cheese is the most well-known artisanal cheese produced in Brazil. Although its production includes a step to remove fungi from the cheese surface, in recent years some cheesemakers have preserved the autochthonous fungi grown during ripening due to an interest in the sensory characteristics attributed to these microorganisms. In this work, the mycobiota of artisanal cheeses produced in the Canastra region was characterized based on ITS marker gene analysis. A total of 96 artisanal cheeses from 16 different farms across 9 cities were collected during two different periods (dry and wet seasons). The Canastra cheese mycobiota was significantly impacted by the season, the city of production and the farm but altitude did not affect the fungal community of the cheeses analyzed. was most abundant in the majority of samples across both seasons. During the wet season, and were the next most abundant species, followed by and These results highlight the importance of manufacturing practices and seasonality on the fungal composition of Canastra cheeses. These insights are particularly important in light of recent new regulation in Brazil, removing previous obstacles for surface fungi to persist on cheese. These new regulations will allow new approaches to cheese production, and ultimately, novel products.
PubMed: 36817100
DOI: 10.3389/fmicb.2022.1076672 -
Food Technology and Biotechnology Dec 2022Wine yeasts are a heterogeneous microbial group with high enzymatic potential that makes them a useful tool in winemaking. With a better understanding of their...
RESEARCH BACKGROUND
Wine yeasts are a heterogeneous microbial group with high enzymatic potential that makes them a useful tool in winemaking. With a better understanding of their oenological properties, selection procedures can be optimised to obtain more efficient strains. The present study aims to isolate and select yeasts from wine grape surface by studying their production of enzymes that hydrolyse plant cell wall polymers and by linking them to different technological parameters and antioxidant activity of wines.
EXPERIMENTAL APPROACH
Yeasts that are able to produce carbohydrolases and related enzymes of oenological importance were firstly selected on plates and subsequently identified. Then, a secondary selection of yeasts was carried out according to technological effects of their extracellular enzyme extracts on short macerations. In this way, the colour extraction, total polyphenol content, clarification, filterability and antioxidant activity were studied. This approach makes it possible to correlate the microorganism capacity to produce cell wall-depolymerizing enzymes with their technological effects.
RESULTS AND CONCLUSIONS
From 366 isolates, 96 strains (26.2%) showed at least one of the polysaccharidase activities and 55 strains (57.3%) of them exhibited activities of multiple enzymes that degrade plant cell wall polymers. Sixteen strains were selected and identified as , , and . Pectinolytic enzymes had the highest hydrolytic activity. had a broader enzyme blend and higher activity, dominated by pectinases and followed by xylanases and cellulases. Moreover, the m7-2 strain produced high amounts of polysaccharidase and this was strain-dependent. Strains that produced enzyme extracts with a wide range of activities that were also the highest, also had the best chromatic and technological properties. Cluster analysis confirmed that R-22, m11-2, m86-1 and m86-2 and m7-2 could be correlated with a better effect on filterability, clarification and extraction of bioactive compounds, encouraging future studies regarding their application in winemaking.
NOVELTY AND SCIENTIFIC CONTRIBUTION
The study of yeast multi-enzymatic systems impacting the grape maceration process enables a proper selection criterion for wine yeasts to improve colour extraction, technological parameters and antioxidant activity of Malbec wine. This work shows that and have a high enzymatic potential for oenological purposes.
PubMed: 36816877
DOI: 10.17113/ftb.60.04.22.7777 -
Letters in Applied Microbiology Feb 2023Maize is one of the most cultivated species and requires agrochOPemicals for nutrition and pathogen control. Fusarium verticillioides is responsible for damaging plants...
Maize is one of the most cultivated species and requires agrochOPemicals for nutrition and pathogen control. Fusarium verticillioides is responsible for damaging plants and stored grains. Plants naturally exposed to stresses have defense mechanisms that are triggered by chemical or biological agents, known as induced systemic resistance. In this study, the yeast Torulaspora globosa (strain CCA6S01) was evaluated as an immune response promoter in maize against F. verticillioides. The treatments started 4 days after maize emergence and consisted of control (saline solution), acetylsalicylic acid (ASA, 100 mg/L), yeast cells (1 × 105 cells/mL), or yeast metabolites (cell-free filtrates). After running the treatments, the plants were inoculated with 1 mL of a F. verticillioides suspension at a concentration of 1 × 106 spores/mL. The application of yeast cells provided similar results to ASA treatment, a known inducer of plant resistance. Yeast cells provided maize plants with fewer rot symptoms and higher activities of enzymes related to plant resistance. Thus, we concluded that T. globosa (strain CCA6S01) might be used in agriculture practice as a plant protection agent. It can help to decrease the application of fungicides in the field and maintain plant productivity under stress.
Topics: Zea mays; Fusarium; Promoter Regions, Genetic; Plant Diseases
PubMed: 36763790
DOI: 10.1093/lambio/ovac072 -
International Journal of Systematic and... Dec 2022Two strains of a novel ascomycetous yeast species were isolated from rotting wood samples collected in Jiuxi Mountain Forest Park in Yunnan Province, southwest China....
Two strains of a novel ascomycetous yeast species were isolated from rotting wood samples collected in Jiuxi Mountain Forest Park in Yunnan Province, southwest China. Both strains formed one or two spherical ascospores in persistent asci. Phylogenetic analysis of the concatenated sequences of the internal transcribed spacer (ITS) region (ITS1-5.8S-ITS2) and the D1/D2 domain of the large subunit rRNA gene revealed that the novel strains represented a phylogenetically distinct species belonging to the genus . This novel species differed from the type strains of the closest known species, and , by 0.9 and 1.2 % nucleotide substitutions in the D1/D2 domain and 5.3 and 6 % nucleotide substitutions in the ITS region, respectively. The novel species can also be distinguished from and in terms of the ability to assimilate ribitol, succinate and citrate, and its ability to grow at 37 °C. The species name of sp. nov. is proposed with holotype CBS 16004 (Mycobank MB 844535).
Topics: Torulaspora; Wood; Phylogeny; DNA, Ribosomal Spacer; China; DNA, Fungal; Sequence Analysis, DNA; Mycological Typing Techniques; Base Composition; RNA, Ribosomal, 16S; DNA, Bacterial; Bacterial Typing Techniques; Fatty Acids; Saccharomycetales; Ascomycota
PubMed: 36748467
DOI: 10.1099/ijsem.0.005629 -
AIMS Microbiology 2022This research aimed to evaluate the diversity of yeasts recovered from fermented foods gathered from some areas of Northeastern Thailand. The fermented food items...
This research aimed to evaluate the diversity of yeasts recovered from fermented foods gathered from some areas of Northeastern Thailand. The fermented food items included Pla-som, Nham-pla, Kem-buknud, Isan-sausage, Pla-ra, Mhum-neu, Mhum-Khai-pla, Nham-neu, Nham-mu, Kung-joom, Som-pla-noi, and Poo-dong. Their probiotic characteristics were also investigated. A total of 103 yeast isolates of nine genera were identified using 28S rDNA sequencing. The yeast genera were (20.3%), (2.9%), (1.0%), (33.0%), (3.9%), (1.0%), (28.2%), (2.9%), and (6.8%). Based on probiotic characteristic analysis of ten selected yeast strains, KKKS4-1 showed the strongest probiotic characteristics in terms of hemolytic activity, antimicrobial activity against pathogenic bacteria, tolerance to low pH and bile salt and hydrophobicity. Isolated yeasts with probiotic characteristics may be useful in fermented food and animal feed production to improve their nutritional values.
PubMed: 36694589
DOI: 10.3934/microbiol.2022037 -
Microorganisms Dec 2022(1) Background: Wine yeast research offers the possibility of isolating new strains with distinct metabolic properties due to the geographical location of the vineyard...
(1) Background: Wine yeast research offers the possibility of isolating new strains with distinct metabolic properties due to the geographical location of the vineyard and the processes used in winemaking. Our study deals with the isolation and identification of six yeasts from spontaneously fermented wine wort from Romania and their characterization as new potential starter culture for traditional beverages, for food industry or biomedicine. (2) Materials and methods: The isolates were identified using conventional taxonomy tests, phenotypic phylogeny analysis (Biolog YT), MALDI-TOF mass spectrometry, PCR-RFLP, and sequencing of the ITS1-5,8S-ITS2 rDNA region. The capacity of the yeasts to grow under thermal, ionic, and osmotic stress was determined. The safe status was confirmed by testing virulence and pathogenicity factors. Assays were performed in order to evaluate the growth inhibition of strains and determine the antimicrobial mechanism of action. (3) Results and discussions: The yeast isolates were identified as belonging to the , , , , and genera. All the isolates were able to develop under the tested stress conditions and were confirmed as safe. With the exception of CMGB-MS1-1, all the isolates showed good antimicrobial activity based on competition for iron ions or production of killer toxins. (4) Conclusions: The results revealed the resistance of our yeasts to environmental conditions related to industrial and biomedical applications and their high potential as starter cultures and biocontrol agents, respectively.
PubMed: 36677329
DOI: 10.3390/microorganisms11010037 -
FEMS Yeast Research Jan 2023In this study, the effect of five different Torulaspora delbrueckii strains in combination with an ale type Saccharomyces cerevisiae on physical, chemical,...
In this study, the effect of five different Torulaspora delbrueckii strains in combination with an ale type Saccharomyces cerevisiae on physical, chemical, microbiological, aroma composition, and sensory profiles of beer were examined. The ethyl alcohol content of produced beers ranged from 5.46% (v/v) to 5.93% (v/v), while the highest alcohol amount was obtained using a pure culture of S. cerevisiae. The major volatiles among beer aroma compounds was acetaldehyde, n-propanol, 3-methyl-butanol, 2-methyl-butanol, ethyl acetate, isoamyl acetate, 2,3-butanedione, and 2,3-pentanedione. It was ascertained that the total amount of higher alcohols was higher in the S. cerevisiae control beer compared to all mixed fermentations. Total ester levels were higher in all the mixed culture beers than the control beer. Sensory evaluation showed that all the mixed cultures of S. cerevisiae and T. delbrueckii positively influenced the sensory profile of the beers. Strain Y1031 was the most preferred and was characterized as rich in hop aroma and full bodied. It is therefore a suitable strategy to use T. delbrueckii in mixed fermentations with S. cerevisiae to produce beer with a distinctive flavor. The results demonstrate that, T. delbrueckii strains isolated or commercialized for winemaking can be equally employed as well in brewing.
Topics: Saccharomyces cerevisiae; Fermentation; Torulaspora; Beer; Wine; Ethanol; Butanols
PubMed: 36669755
DOI: 10.1093/femsyr/foad006 -
Foods (Basel, Switzerland) Jan 2023Non-Saccharomyces (NS) yeasts are gaining popularity in modern winemaking for improving wine quality. Climate change is one of the biggest challenges winegrowing now...
Non-Saccharomyces (NS) yeasts are gaining popularity in modern winemaking for improving wine quality. Climate change is one of the biggest challenges winegrowing now faces in warm regions. Here, Lachancea thermotolerans LtS1 and Torulaspora delbrueckii TdS6 combined with Saccharomyces cerevisiae ScS13 isolated from Assyrtiko grapes from Santorini island were evaluated in grape must fermentation with the aim to mitigate major consequences of temperature rise. Different inoculation protocols were evaluated, including simultaneous and sequential mixed-strain inoculations, displaying significant variation in the chemical and kinetic characteristics. Both LtS1 and TdS6 could raise the titratable acidity (TA). TdS6 also reduced the volatile acidity (VA) and was thus chosen for further evaluation in microvinifications and pilot-scale fermentations. Consistent with lab-scale trials, sequential inoculation exhibited the longest persistence of TdS6 resulting in minimum VA levels. Diethyl succinate, ethyl propanoate, and ethyl isobutyrate were significantly increased in sequential inoculations, although a decline in the net total ester content was observed. On the other hand, significantly higher levels of TA, succinic acid, and 2-methylpropanoic were associated with sequential inoculation. The overall performance of TdS6 coupled with a high compatibility with S. cerevisiae suggests its use in the fermentation of Santorini-Assyrtiko or other high sugar musts for the production of structured dry or sweet wines.
PubMed: 36613407
DOI: 10.3390/foods12010191 -
Foods (Basel, Switzerland) Dec 2022This study aimed to investigate in vitro the probiotic potential of three yeasts strains (BB06, OBT05, and MT07) isolated from agro-food natural sources. Screening was...
This study aimed to investigate in vitro the probiotic potential of three yeasts strains (BB06, OBT05, and MT07) isolated from agro-food natural sources. Screening was performed, including several functional, technological, and safety aspects of the yeast strains, in comparison to a reference Saccharomyces boulardii, to identify the ones with suitable probiotic attributes in aquaculture. The yeast strains were identified by 5.8S rDNA-ITS region sequencing as Metschnikowia pulcherrima OBT05, Saccharomyces cerevisiae BB06, and Torulaspora delbrueckii MT07. All yeast strains were tolerant to different temperatures, sodium chloride concentrations, and wide pH ranges. S. cerevisiae BB06 showed a strong and broad antagonistic activity. Moreover, the S. cerevisiae strain exhibited a high auto-aggregation ability (92.08 ± 1.49%) and good surface hydrophobicity to hexane as a solvent (53.43%). All of the yeast strains have excellent antioxidant properties (>55%). The high survival rate in the gastrointestinal tract (GIT) can promote yeast isolates as probiotics. All yeast strains presented a resistance pattern to the antibacterial antibiotics. Non-hemolytic activity was detected. Furthermore, freeze-drying with cryoprotective agents maintained a high survival rate of yeast strains, in the range of 74.95−97.85%. According to the results obtained, the S. cerevisiae BB06 strain was found to have valuable probiotic traits.
PubMed: 36613340
DOI: 10.3390/foods12010124