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Microorganisms Jan 2022() is responsible for grape infection and damage to the winemaking and table grape sectors. Although anti- chemicals are available, they are considered unsustainable...
BACKGROUND
() is responsible for grape infection and damage to the winemaking and table grape sectors. Although anti- chemicals are available, they are considered unsustainable for resistance phenomenon and adverse effects on the environment and human health. Research is focused on developing alternative approaches, such as exploiting biological control agents (BCAs). In this context, 19 yeasts of the genera , , , and were tested as antimicrobial agents against development.
METHODS
A combination of in vitro tests based on dual-culture methods, volatile organic compound production assay, laboratory tests on grape berries (punctured and sprayed with yeasts) and field experiments based on yeast treatments on grapes in vineyards allowed the selection of two potential BCAs.
RESULTS
DiSVA 269 and DiSVA 211 exhibited the best ability to contain the development of , showing the severity, the decay and the McKinney index lower than a commercial biological formulation consisting of a mixture of two different strains, which were used as positive controls.
CONCLUSIONS
The results indicated that the selected strains were effective BCA candidates to counteract in the field, applying them in the partial or total replacement of conventional treatments.
PubMed: 35208653
DOI: 10.3390/microorganisms10020200 -
Microorganisms Sep 2022The use of yeasts as starter cultures was boosted with the emergence of large-scale fermentations in the 20th century. Since then, has been the most common and widely... (Review)
Review
The use of yeasts as starter cultures was boosted with the emergence of large-scale fermentations in the 20th century. Since then, has been the most common and widely used microorganism in the food industry. However, species have also been used as an adjuvant in cheese production or as starters for coffee, cocoa, vegetable, meat, beer, and wine fermentations. A thorough screening of candidate is sometimes performed to obtain the best performing strains to enhance specific features. Some commonly selected species include (teleomorph ) (wine), (teleomorph ) (coffee), (teleomorph ) (cheese), and (teleomorph ) and (teleomorph ) (cocoa). These species are associated with the production of key metabolites (food aroma formation) and different enzymes. However, safety-associated selection criteria are often neglected. It is widely known that some species are opportunistic human pathogens, with important clinical relevance. Here, the physiology and metabolism of species are addressed, initially emphasizing their clinical aspects and potential pathogenicity. Then, species used in food fermentations and their functional roles are reported. We recommended that not be used as food cultures if safety assessments are not performed. Some safety features are highlighted to help researchers choose methods and selection criteria.
PubMed: 36144457
DOI: 10.3390/microorganisms10091855 -
Biology Letters Jul 2019Animals such as bumblebees use chemosensory cues to both locate and evaluate essential resources. Increasingly, it is recognized that microbes can alter the quality of...
Animals such as bumblebees use chemosensory cues to both locate and evaluate essential resources. Increasingly, it is recognized that microbes can alter the quality of foraged resources and produce metabolites that may act as foraging cues. The distinct nature of these chemosensory cues however and their use in animal foraging remain poorly understood. Here, we test the hypothesis that species of nectar-inhabiting microbes differentially influence pollinator attraction and feeding via microbial metabolites produced in nectar. We first examined the electrophysiological potential for bumblebee (Bombus impatiens) antennal olfactory neurons to respond to microbial volatile organic compounds (mVOCs), followed by an olfactory preference test. We also assessed gustatory preferences for microbial-altered nectar through both no-choice and choice feeding assays. Antennal olfactory neurons responded to some mVOCs, and bees preferred nectar solutions inoculated with the bacterium Asaia astilbes over the yeast Metschnikowia reukaufii based on volatiles alone. However, B. impatiens foragers consumed significantly more Metschnikowia-inoculated nectar, suggesting distinct roles for mVOCs and non-volatile metabolites in mediating both attraction and feeding decisions. Collectively, our results suggest that microbial metabolites have significant potential to shape interspecific, plant-pollinator signalling, with consequences for forager learning, economics and floral host reproduction.
Topics: Animals; Bees; Flowers; Metschnikowia; Plant Nectar; Plants; Pollination; Smell
PubMed: 31311487
DOI: 10.1098/rsbl.2019.0132 -
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 -
Foods (Basel, Switzerland) Sep 2021The pre and postharvest disease named 'aqueous spot' is an emerging risk for sweet cherries growing in Jerte Valley (Cáceres, Spain). Early stages of the disease appear...
The pre and postharvest disease named 'aqueous spot' is an emerging risk for sweet cherries growing in Jerte Valley (Cáceres, Spain). Early stages of the disease appear in the tree, but it is usually detected after harvesting, during the postharvest period. Symptoms include the appearance of skin discolouration and translucency in the shoulder areas. At the most advanced stages, a mycelium of white colour partially or completely covers the fruit. This manuscript provides a detailed description of the microbes involved in this disease, such as bacteria, yeasts, and moulds. Microbes of different cherry cultivars were studied during two consecutive seasons (2019 and 2020). The counts of bacteria and yeast in damaged tissues were higher (7.05 and 6.38 log10 CFU/g for total aerobic mesophilic microbes and yeasts, respectively) than sound tissues (6.08 and 5.19 log10 CFU/g, respectively). The Enterobacterales order dominated the bacteria population. Among yeasts, , in 2019, and and , in 2020, were consistently isolated from all samples. The presence of moulds was inconsistently detected at the early stage of this disease by plate counts. However, microscopic observations revealed the presence of hyphae in cherry flesh. Different pathogenic moulds were identified, although white mycelium, identified as by molecular methods, was consistently isolated at later stages. Inoculation tests confirmed the involvement of white-mycelium in the development of this new postharvest disease in the Jerte Valley. Its combination with Enterobacterales enhanced the evolution of rotting, whereas the combination with yeasts decreased and delayed the symptoms. This work presents the first report of a consortia of microorganisms implicated in the development of 'aqueous spot', an emerging disease in sweet cherry cultivars in the Jerte Valley.
PubMed: 34681330
DOI: 10.3390/foods10102281 -
Scientific Reports Jun 2022The gut mycobiota has never been studied either during pregnancy or in patients with gestational diabetes (GDM). This study aimed to analyze the fecal mycobiota of GDM...
The gut mycobiota has never been studied either during pregnancy or in patients with gestational diabetes (GDM). This study aimed to analyze the fecal mycobiota of GDM patients during the second (T2) and third (T3) trimester of pregnancy and to compare it with the mycobiota of pregnant normoglycemic women (controls). Forty-one GDM patients and 121 normoglycemic women were studied. GDM mycobiota was composed almost exclusively by the Ascomycota phylum; Basidiomicota accounted for 43% of the relative frequency of the controls. Kluyveromyces (p < 0.001), Metschnikowia (p < 0.001), and Pichia (p < 0.001) showed a significantly higher frequency in GDM patients, while Saccharomyces (p = 0.019), were more prevalent in controls. From T2 to T3, a reduction in fungal alpha diversity was found in GDM patients, with an increase of the relative frequency of Candida, and the reduction of some pro-inflammatory taxa. Many associations between fungi and foods and nutrients were detected. Finally, several fungi and bacteria showed competition or co-occurrence. Patients with GDM showed a predominance of fungal taxa with potential inflammatory effects when compared to normoglycemic pregnant women, with a marked shift in their mycobiota during pregnancy, and complex bacteria-fungi interactions.
Topics: Bacteria; Diabetes, Gestational; Feces; Female; Humans; Pregnancy; Pregnancy Trimesters; Pregnant Women
PubMed: 35654937
DOI: 10.1038/s41598-022-13438-0 -
Journal of Fungi (Basel, Switzerland) Jul 2022The aim of this study was to investigate the effects of crude extracts of β-glucosidase from SLY-4, F2-24 and HX-13 (termed as SLY-4E, F2-24E and HX-13E) on the...
The aim of this study was to investigate the effects of crude extracts of β-glucosidase from SLY-4, F2-24 and HX-13 (termed as SLY-4E, F2-24E and HX-13E) on the flavor complexity and typicality of Cabernet Sauvignon wines. The grape must was fermented using with single or mixed SLY-4E, F2-24E and HX-13E. The physicochemical characteristics, volatile aroma compounds, total anthocyanins and sensory attributes of the wines were determined. Adding SLY-4E, F2-24E and HX-13E in wines resulted in a decrease in the anthocyanin content, total acids and volatile acids in wines but an increase in the content of terpenes, benzene derivatives, higher alcohols and esters, which may enhance wine sensory qualities and result in loss of wine color. Different adding strategies of β-glucosidase led to a variety of effects on wine aroma. S/H/F-Ew significantly increased the content of benzene derivatives, higher alcohols and long-chain fatty acid esters, which enhanced the fruity and floral flavor of wines. F2-24E significantly increased the content of short- and medium-chain fatty acid esters, acetate esters and carbonyl compounds. The results indicated that the mixed addition of non- crude extracts and co-fermentation with could further improve wine flavor quality.
PubMed: 35887465
DOI: 10.3390/jof8070710 -
Toxins Jun 2023is a major aflatoxin B, posing significant health concerns to humans, crops, and producer fungi. Due to the undesirable consequences of the usage of synthetic...
is a major aflatoxin B, posing significant health concerns to humans, crops, and producer fungi. Due to the undesirable consequences of the usage of synthetic fungicides, biological control using yeasts has gained more attention. In this study, eight isolates of epiphytic yeasts belonging to sp., sp. and sp., which have been identified as antagonists, were isolated from different plants, including grapes, blueberries, hawthorns, hoşkıran, beans and grape leaf. While volatile organic compounds (VOCs) produced by DN-FY, aff. DN-MP and aff. 32-AMM reduced in vitro mycelial growth and sporulation, only VOCs produced by aff. 1-UDM were found to be effective at reducing in vitro AFB production. All yeasts reduced the mycelial growth of by 76-91%, while AFB production reduced to 1.26-10.15 ng/g and the control plates' growth was 1773 ng/g. The most effective yeast, aff. DN-HS, reduced growth and aflatoxin B production on hazelnuts. The AFB content on hazelnuts reduced to 333.01 ng/g from 536.74 ng/g. To our knowledge, this is the first report of yeasts isolated from plants being tested as potential biological control agents to reduce AFB production on hazelnuts.
Topics: Humans; Aflatoxin B1; Yeasts; Aspergillus; Fungi; Aspergillus flavus; Metschnikowia; Vitis
PubMed: 37368702
DOI: 10.3390/toxins15060402 -
Foods (Basel, Switzerland) Jan 2023A fermentation of Fiano di Avellino grape must was carried out at 9°C with the aim of selecting cryotolerant yeast strains and testing their fermentative performances...
A fermentation of Fiano di Avellino grape must was carried out at 9°C with the aim of selecting cryotolerant yeast strains and testing their fermentative performances and volatile production following molecular characterization. A total of 20 yeast cultures were isolated at different fermentation stages. Based on molecular identification and characterization, (.) , (.) , (.) , (.) , , and were found to be the yeast species dominating the fermentation. has been rarely isolated in vineyards and never in the cellar environment. Moreover, in this study, is detected for the first time in vine-wine environments. Both and co-occurred with when grapes were micro-fermented at low temperatures. The growth kinetics of the three species were greatly affected by the fermentation temperature. As a consequence, Fiano wines obtained with and significantly differed from those made by in terms of chemical and volatile composition.
PubMed: 36766056
DOI: 10.3390/foods12030526 -
Saudi Journal of Biological Sciences Jul 2021Pomegranate peels (PPW) as municipal waste is inexpensive biomass that could be a renewable source of sugars particularly rich in hemicellulosic contents. The subsequent...
Pomegranate peels (PPW) as municipal waste is inexpensive biomass that could be a renewable source of sugars particularly rich in hemicellulosic contents. The subsequent conversion of available sugars in PPW can provide prospective strategy for cost-effective bioenergy production. In this study, an experimental setup based on CCD was implemented with the aim of bioconversion of biomass into bioethanol. The factors considered were Hydrochloric acid concentration (X), the hydrolysis temperature (X) and time (X) for optimization with dilute Hydrochloric acid (HCl) saccharification. The present study investigates the optimised level of bioethanol synthesis from acid pre-treated PPW explained by RSM. Subsequently, three yeasts viz. K7, sp. Y31 and Y34 were utilized for fermentation of acid hydrolysed and detoxified feed stocks. Optimum values of reducing sugars 48.02 ± 0.02 (gL) and total carbohydrates 205.88 ± 0.13 (gL) were found when PPW was hydrolyzed with 1% HCl concentration at 100˚C of temperature for 30 min. Later on, fermentation of PPWH after detoxification with 2.5% activated charcoal. The significant ethanol (g ethanol/g of reducing sugars) yields after fermentation with sp. Y31 and Y34 found to be 0.40 ± 0.03 on day 5 and 0.41 ± 0.02 on last day of experiment correspondingly. K7 also produce maximum ethanol 0.40 ± 0.00 on last day of incubation utilizing the PPWH. The bioconversion of commonly available PPW into bioethanol as emphasize in this study could be a hopeful expectation and also cost-effective to meet today energy crisis.
PubMed: 34220222
DOI: 10.1016/j.sjbs.2021.04.049