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Frontiers in Microbiology 2022Luzhou-flavoured liquor is one of Chinese most popular distilled liquors. Hundreds of flavoured components have been detected from this liquor, with esters as its...
Luzhou-flavoured liquor is one of Chinese most popular distilled liquors. Hundreds of flavoured components have been detected from this liquor, with esters as its primary flavouring substance. Among these esters, ethyl hexanoate was the main component. As an essential functional microbe that produces ethyl hexanoate, yeast is an important functional microorganism that produces ethyl hexanoate. The synthesis of ethyl hexanoate in yeast mainly involves the lipase/esterase synthesis pathway, alcohol transferase pathway and alcohol dehydrogenase pathway. In this study, whole-genome sequencing of Y-1 isolated from a Chinese liquor fermentation starter, a fermented wheat starter containing brewing microorganisms, was carried out using the Illumina HiSeq X Ten platform. The sequence had a length of 15,127,803 bp with 34.56% GC content, encoding 7,024 CDS sequences, 69 tRNAs and 1 rRNA. Then, genome annotation was performed using three high-quality databases, namely, COG, KEGG and GO databases. The annotation results showed that the ko7019 pathway of gene 6,340 contained the Eht1p enzyme, which was considered a putative acyltransferase similar to Eeb1p and had 51.57% homology with two known medium-chain fatty acid ethyl ester synthases, namely, Eht1 and Eeb1. Ethyl hexanoate in was found to be synthesised through the alcohol acyltransferase pathway, while acyl-coenzyme A and alcohol were synthesised under the catalytic action of Eht1p. The results of this study are beneficial to the exploration of key genes of ester synthesis and provide reference for the improvement of liquor flavoured.
PubMed: 35586860
DOI: 10.3389/fmicb.2022.891387 -
Brazilian Journal of Microbiology :... Sep 2022The recent realisation regarding the potentiality of the long-neglected non-Saccharomyces yeasts in improving the flavour profile and functionality of alcoholic...
The recent realisation regarding the potentiality of the long-neglected non-Saccharomyces yeasts in improving the flavour profile and functionality of alcoholic beverages has pushed researchers to search for such potent strains in many sources. We studied the fungal diversity and the rice beer production capability of the fungal strains isolated from emao-a traditional rice beer starter culture of the Boro community. Fifty distinct colonies were picked from mixed-culture plates, of which ten representative morphotypes were selected for species identification, and simultaneous saccharification and beer fermentation (SSBF) assay. The representative isolates were identified as Hyphopichia burtonii (Hbur-FI38, Hbur-FI44, Hbur-FI47 & Hbur-FI68), Saccharomyces cerevisiae (Scer-FI51), Wickerhamomyces anomalus (Wano-FI52), Candida carpophila (Ccar-FI53), Mucor circinelloides (Mcir-FI60), and Saccharomycopsis malanga (Smal-FI77 and Smal-FI84). The non-Saccharomyces yeast strains Hbur-FI38, Hbur-FI44, Ccar-FI53, and Smal-FI77 showed SSBF capacity on rice substrate producing beer that contained 7-10% (v/v) ethanol. A scaled-up fermentation assay was performed to assess the strain-wise fermentation behaviour in large-scale production. The nutritional, functional, and sensory qualities of the SSBF strain fermented beer were compared to the beer produced by emao. All the strains produced beer with reduced alcohol and energy value while compared to the traditional starter emao. Beer produced by both the strains of H. burtonii stood out with higher ascorbic acid, phenol, and antioxidant property, and improved sensory profile in addition to reduced alcohol and energy value. Such SSBF strains are advantageous over the non-SSBF S. cerevisiae strains as the former can be used for direct beer production from rice substrates.
Topics: Alcoholic Beverages; Beer; Ethanol; Fermentation; Oryza; Saccharomyces cerevisiae
PubMed: 35488168
DOI: 10.1007/s42770-022-00765-7 -
Insects Apr 2022Here, we aimed to produce a natural food preservative using a crude extract from edible, immunized larvae (iTME), injected with edible bacteria using an edible solvent....
Here, we aimed to produce a natural food preservative using a crude extract from edible, immunized larvae (iTME), injected with edible bacteria using an edible solvent. Results showed that iTME had concentration-dependent inhibitory activity against food-poisoning bacteria , , and , as well as against harmful fungi , , and . Moreover, iTME showed antimicrobial activity against beneficial microorganisms and , but not . Furthermore, the minimum inhibitory concentration of iTME against , , and was 1 mg/mL, and iTME did not lose its inhibitory activity when treated at varying temperature, pH, and salinity. In addition, the antibacterial activity was lost after reacting the iTME with trypsin and chymotrypsin. The addition of iTME to Ganjang inoculated with harmful bacteria inhibited bacterial growth. Therefore, we propose that iTME can be used as a safe natural preservative to prolong food shelf life by inhibiting the growth of food-poisoning bacteria in a variety of foods, including traditional sauces.
PubMed: 35447823
DOI: 10.3390/insects13040381 -
Toxins Feb 2022The killer strains of and species secrete antimicrobial proteins called killer toxins which are active against selected fungal phytopathogens. In our research, we...
The killer strains of and species secrete antimicrobial proteins called killer toxins which are active against selected fungal phytopathogens. In our research, we attempted to investigate the role of plasma membrane pleiotropic drug resistance (PDR) transporters (Pdr5p and Snq2p) in the mechanism of defense against killer toxins. mutant strains with strengthened or weakened pleiotropic drug resistance due to increased or reduced number of mentioned PDR efflux pumps were tested for killer toxin susceptibility. The present study demonstrates the influence of the Snq2p efflux pump in immunity to BS91 killer toxin. It was also shown that the activity of killer toxins of AII4b, KI2a, MI1a and CBS767 strains is regulated by other transporters than those influencing killer toxin activity. In turn, this might be related to the functioning of the Pdr5p transporter and a complex cross-talk between several regulatory multidrug resistance networks. To the best of our knowledge, this is the first study that reports the involvement of PDR transporters in the cell membrane of susceptible microorganisms in resistance to killer yeasts' toxins.
Topics: Cell Membrane; Debaryomyces; Drug Resistance; Membrane Transport Proteins; Saccharomyces cerevisiae; Saccharomycetales; Toxins, Biological
PubMed: 35324677
DOI: 10.3390/toxins14030180 -
Foods (Basel, Switzerland) Feb 2022Gray mold decay is a widespread postharvest disease in tomato that results from infection by the pathogen , leading to huge economic losses. The objective of this study...
Gray mold decay is a widespread postharvest disease in tomato that results from infection by the pathogen , leading to huge economic losses. The objective of this study was to select the most effective antagonistic yeast to control tomato gray mold from six potential biocontrol agents and to investigate the possible control mechanism. The results showed that the yeast was the most effective in inhibiting among the six strains both in vivo and in vitro on tomato, with a colony diameter of 11 mm, a decay diameter of 20 mm, and the lowest decay incidence (53%)-values significantly smaller and lower than the values recorded for the control group and the other yeasts. The efficacy of the control depended on the increase in yeast concentration, and the decay incidence and lesion diameter were reduced to 31%, 28% and 7 mm, 6 mm, respectively, when treated with 1 × 10 and 1 × 10 cells/mL . In addition, was able to rapidly colonize and stably multiply in tomato, occupying the space to control pathogen infection. was also able to motivate the defense mechanism of tomato with stimulation of defense-related enzymes PPO, POD, APX, and SOD and promotion of the content of total phenols and flavonoid compounds. All these results suggest that exhibited exceptional ability to control gray mold in tomato.
PubMed: 35267353
DOI: 10.3390/foods11050720 -
Frontiers in Microbiology 2021Flor yeast velum is a biofilm formed by certain yeast strains that distinguishes biologically aged wines such as Sherry wine from southern Spain from others. Although...
Revealing the Yeast Diversity of the Flor Biofilm Microbiota in Sherry Wines Through Internal Transcribed Spacer-Metabarcoding and Matrix-Assisted Laser Desorption/Ionization Time of Flight Mass Spectrometry.
Flor yeast velum is a biofilm formed by certain yeast strains that distinguishes biologically aged wines such as Sherry wine from southern Spain from others. Although is the most common species, 5.8 S-internal transcribed spacer (ITS) restriction fragment length polymorphism analyses have revealed the existence of non- species. In order to uncover the flor microbiota diversity at a species level, we used ITS (internal transcribed spacer 1)-metabarcoding and matrix-assisted laser desorption/Ionization time of flight mass spectrometry techniques. Further, to enhance identification effectiveness, we performed an additional incubation stage in 1:1 wine:yeast extract peptone dextrose (YPD) before identification. Six species were identified: , , , , , and , two of which were discovered for the first time ( and ) in Sherry wines. We analyzed wines where non- yeasts were present or absent to see any potential link between the microbiota and the chemical profile. Only 2 significant volatile chemicals (out of 13 quantified), ethanol and ethyl lactate, and 2 enological parameters (out of 6 quantified), such as pH and titratable acidity, were found to differ in long-aged wines. Although results show a low impact where the non- yeasts are present, these yeasts isolated from harsh environments (high ethanol and low nutrient availability) could have a potential industrial interest in fields such as food microbiology and biofuel production.
PubMed: 35222316
DOI: 10.3389/fmicb.2021.825756 -
Molecules (Basel, Switzerland) Feb 2022The effect of different pretreatment approaches based on alkali (NaOH)/hydrogen peroxide (HO) on willow sawdust (WS) biomass, in terms of delignification efficiency,...
The effect of different pretreatment approaches based on alkali (NaOH)/hydrogen peroxide (HO) on willow sawdust (WS) biomass, in terms of delignification efficiency, structural changes of lignocellulose and subsequent fermentation toward ethanol, was investigated. Bioethanol production was carried out using the conventional yeast as well as three non-conventional yeasts strains, i.e., , , separately and in co-cultures. The experimental results showed that a two-stage pretreatment approach (NaOH (0.5% /) for 24 h and HO (0.5% /) for 24 h) led to higher delignification (38.3 ± 0.1%) and saccharification efficiency (31.7 ± 0.3%) and higher ethanol concentration and yield. Monocultures of or and co-cultures with exhibited ethanol yields in the range of 11.67 ± 0.21 to 13.81 ± 0.20 g/100 g total solids (TS). When WS was subjected to HO (0.5% /) alone for 24 h, the lowest ethanol yields were observed for all yeast strains, due to the minor impact of this treatment on the main chemical and structural WS characteristics. In order to decide which is the best pretreatment approach, a detailed techno-economical assessment is needed, which will take into account the ethanol yields and the minimum processing cost.
Topics: Biofuels; Ethanol; Fermentation; Phytochemicals; Spectrum Analysis; Wood; Yeasts
PubMed: 35209130
DOI: 10.3390/molecules27041344 -
Microorganisms Jan 2022Sourdough is one of the oldest starters traditionally used for making baked goods, offering several advantages to the sensory, rheology, and shelf life of final...
Sourdough is one of the oldest starters traditionally used for making baked goods, offering several advantages to the sensory, rheology, and shelf life of final products. The present study investigated, for the first time, the microbiota of spontaneously fermented Maiorca dough samples collected from bakeries located in Sicily (Italy). Four sourdough samples (M1, M2, M3, and M4), were produced using Host. var. Koern (Maiorca grain) were subjected to LAB and yeasts isolation and identification at the species level. The in-depth characterization of the lactobacilli population revealed that and unquestionably dominated the Maiorca sourdough ecosystem. Concerning the yeasts community, high species diversity was found. and were the most frequently isolated species. In addition, and were also detected. Investigations on both pro-technological and functional traits of the isolated strains could lead to the selection of starters for the production of baked goods.
PubMed: 35208738
DOI: 10.3390/microorganisms10020283 -
Journal of Fungi (Basel, Switzerland) Jan 2022This study investigated the fermentation performances and aroma compositions of synthetic grape juice that was fermented by four indigenous non- yeast isolates that were...
Evaluation of Four Indigenous Non- Yeasts Isolated from the Shangri-La Wine Region (China) for Their Fermentation Performances and Aroma Compositions in Synthetic Grape Juice Fermentation.
This study investigated the fermentation performances and aroma compositions of synthetic grape juice that was fermented by four indigenous non- yeast isolates that were obtained from the Shangri-La wine region (China): (AD-58), (BZL-28), (BZL-11), and (DR-110), in comparison to those of (EC1118). The four indigenous non- yeasts showed a lower fermentative capacity and a lower conversion rate of sugar to alcohol, but a higher yield of volatile acidity. (DR-110) had a greater ability to produce numerous esters and short-chain fatty acids and the representative flavors of its fermented medium were fruity and fatty. (BZL-28), interestingly, exhibited great capacity in the formation of many monoterpenes, particularly ()-β-ocimene, -β-ocimene, linalool, citral, and geraniol and its fermented medium was characterized by a strong fruity (citrus-like) and floral flavor. (AD-58) and (BZL-11) only mildly affected the aroma profiles of their resultant fermented media, since the concentrations of most of the volatiles that were produced by these two isolates were much lower than their sensory thresholds. The four indigenous non- yeasts exhibited distinctive fermentation performances and aroma production behaviors. In particularly, (DR-110) and (BZL-28) have shown good potential in enhancing the aromas and complexity of wine.
PubMed: 35205900
DOI: 10.3390/jof8020146 -
International Journal of Molecular... Jan 2022The objective of the current study was to examine the effects of yeasts on intestinal health and transcriptomic profiles from the distal intestine and spleen tissue of...
The objective of the current study was to examine the effects of yeasts on intestinal health and transcriptomic profiles from the distal intestine and spleen tissue of Atlantic salmon fed SBM-based diets in seawater. (CJ) and (WA) yeasts were heat-inactivated with spray-drying (ICJ and IWA) or autolyzed at 50 °C for 16 h (ACJ and AWA), followed by spray-drying. Six diets were formulated, one based on fishmeal (FM), a challenging diet with 30% soybean meal (SBM) and four other diets containing 30% SBM and 10% of each of the four yeast fractions (i.e., ICJ, ACJ, IWA and AWA). The inclusion of CJ yeasts reduced the loss of enterocyte supranuclear vacuolization and reduced the population of CD8α labeled cells present in the lamina propria of fish fed the SBM diet. The CJ yeasts controlled the inflammatory responses of fish fed SBM through up-regulation of pathways related to wound healing and taurine metabolism. The WA yeasts dampened the inflammatory profile of fish fed SBM through down-regulation of pathways related to toll-like receptor signaling, C-lectin receptor, cytokine receptor and signal transduction. This study suggests that the yeast species, and are novel high-quality protein sources with health-beneficial effects in terms of reducing inflammation associated with feeding plant-based diets to Atlantic salmon.
Topics: Animal Feed; Animals; Candida; Intestines; Saccharomycetales; Salmo salar; Glycine max; Transcriptome
PubMed: 35163597
DOI: 10.3390/ijms23031675