-
Foods (Basel, Switzerland) Sep 2023Microbial inoculation in moromi fermentation has a great influence on the physicochemical and flavour properties of soy sauces. This work investigated the effect of...
Microbial inoculation in moromi fermentation has a great influence on the physicochemical and flavour properties of soy sauces. This work investigated the effect of inoculating and on the flavour formation of early-stage moromi (30 days) fermented at a lower temperature (22 °C) by determining their physicochemical and aroma changes. The results showed that single yeast or LAB inoculation increased the production of amino nitrogen, lactic acid and acetic acid, as well as free amino acids and key flavour components. Particularly, the sequential inoculation of and produced more free amino acids and aromatic compounds, and there might be synergistic effects between these two strains. More characteristic soy sauce flavour compounds, such as benzaldehyde, HEMF, guaiacol and methyl maltol were detected in the sequentially inoculated moromi, and this sample showed higher scores in savoury, roasted and caramel intensities. These results confirmed that sequential inoculation of and could be a choice for the future production of moromi with good flavour and quality under a lower temperature.
PubMed: 37761218
DOI: 10.3390/foods12183509 -
Cureus Feb 2024We report the case of an 84-year-old man with a history of IgG4-related sclerosing cholangitis who was diagnosed with advanced esophageal cancer and underwent radiation...
We report the case of an 84-year-old man with a history of IgG4-related sclerosing cholangitis who was diagnosed with advanced esophageal cancer and underwent radiation and chemotherapy. An implantable central venous access port was placed for chemotherapy and total parenteral nutrition. The patient presented with a fever and received antimicrobial therapy for acute cholangitis but remained febrile, and subsequently, yeast was detected in the aerobic bottle of blood culture obtained from the central venous line. The yeast was identified as . Liposomal amphotericin B was administered, and the central line access port was removed. After confirmation of negative blood cultures and 14 days post treatment, he underwent reinsertion of the central line access port. Due to persistent pain at the insertion site, fluconazole was added for an additional 14 days, and the patient was discharged and transferred to another hospital. is a rare fungal infection with other synonyms including , , and . A literature review of 53 case reports of , , , and was conducted, with a total of 211 cases reviewed. Fungemia was reported in 94% of cases, with central venous catheterization, parental feeding, low birth weight, and immunocompromised status identified as major risk factors. The majority of cases were pediatric, particularly neonatal, and there were reports of nosocomial infections causing outbreaks, with some cases involving the eye such as endophthalmitis or keratitis.
PubMed: 38445156
DOI: 10.7759/cureus.53550 -
Foods (Basel, Switzerland) Oct 2023Currently, non- yeasts are the subject of interest, among other things, for their contribution to the aromatic complexity of wines. In this study, the characterisation...
Currently, non- yeasts are the subject of interest, among other things, for their contribution to the aromatic complexity of wines. In this study, the characterisation of non- yeasts was addressed by their isolation during spontaneous fermentations of organic Verdejo grapes, obtaining a total of 484 isolates, of which 11% were identified by molecular techniques as non- yeasts. Fermentative isolates belonging to the species , , , , , and were analysed. Significant differences were found in the yeast populations established at the different fermentation stages. Interestingly, stood up as a widely distributed species in vineyards, vintages, and fermentation stages. Several of the strains studied stood out for their biotechnological potential in the production of Verdejo wine, showing the presence of relevant enzymatic activity for the release of varietal aromas and the technological improvement of the winemaking process. Three enzymatic activities were found in an important number of isolates, β-glucosidase, protease, and β-lyase, implicated in the positive aromatic impact on this style of white wine. In that sense, all the isolates of presented those activities. isolates were highlighted for their significant β-lyase activity. In addition, was outlined because of its potential to achieve an elevated fermenting power, as well as the lack of lag phase. The results obtained highlight the importance of maintaining the microbial diversity that contributes to the production of wines with unique and distinctive characteristics of the production region.
PubMed: 37835297
DOI: 10.3390/foods12193644 -
Microbial Cell Factories Sep 2015The product yield and titers of biological processes involving the conversion of biomass to desirable chemicals can be limited by environmental stresses encountered by...
BACKGROUND
The product yield and titers of biological processes involving the conversion of biomass to desirable chemicals can be limited by environmental stresses encountered by the microbial hosts used for the bioconversion. One of these main stresses is growth inhibition due to exposure to low pH conditions. In order to circumvent this problem, understanding the biological mechanisms involved in acid stress response and tolerance is essential. Characterisation of wild yeasts that have a natural ability to resist such harsh conditions will pave the way to understand the biological basis underlying acid stress resistance. Pichia anomala possesses a unique ability to adapt to and tolerate a number of environmental stresses particularly low pH stress giving it the advantage to outcompete other microorganisms under such conditions. However, the genetic basis of this resistance has not been previously studied.
RESULTS
To this end, we isolated an acid resistant strain of P. anomala, performed a gross phenotypic characterisation at low pH and also performed a whole genome and total RNA sequencing. By integrating the RNA-seq data with the genome sequencing data, we found that several genes associated with different biological processes including proton efflux, the electron transfer chain and oxidative phosphorylation were highly expressed in P. anomala cells grown in low pH media. We therefore present data supporting the notion that a high expression of proton pumps in the plasma membrane coupled with an increase in mitochondrial ATP production enables the high level of acid stress tolerance of P. anomala.
CONCLUSIONS
Our findings provide insight into the molecular and genetic basis of low pH tolerance in P. anomala which was previously unknown. Ultimately, this is a step towards developing non-conventional yeasts such as P. anomala for the production of industrially relevant chemicals under low pH conditions.
Topics: Adenosine Triphosphate; Amino Acid Sequence; Biomass; Electron Transport; Fungal Proteins; Genome, Fungal; Hydrogen-Ion Concentration; Mitochondria; Models, Molecular; Molecular Sequence Data; Oxidative Phosphorylation; Pichia; Sequence Alignment; Sequence Analysis, RNA; Stress, Physiological; Transcriptome
PubMed: 26376644
DOI: 10.1186/s12934-015-0331-4 -
Brazilian Journal of Microbiology :... Jun 2021Lignocellulosic hydrolysates will also contain compounds that inhibit microbial metabolism, such as organic acids, furaldehydes, and phenolic compounds. Understanding... (Comparative Study)
Comparative Study
Lignocellulosic hydrolysates will also contain compounds that inhibit microbial metabolism, such as organic acids, furaldehydes, and phenolic compounds. Understanding the response of yeasts toward such inhibitors is important to the development of different bioprocesses. In this work, the growth capacity of 7 industrial Saccharomyces cerevisiae and 7 non-Saccharomyces yeasts was compared in the presence of 3 different concentrations of furaldehydes (furfural and 5-hydroxymetil-furfural), organic acids (acetic and formic acids), and phenolic compounds (vanillin, syringaldehyde, ferulic, and coumaric acids). Then, Candida tropicalis JA2, Meyerozyma caribbica JA9, Wickerhamomyces anomalus 740, S. cerevisiae JP1, B1.1, and G06 were selected for fermentation in presence of acetic acid, HMF, and vanillin because they proved to be most tolerant to the tested compounds, while Spathaspora sp. JA1 because its xylose consumption rate. The results obtained showed a dose-dependent response of the yeasts toward the eight different inhibitors. Among the compared yeasts, S. cerevisiae strains presented higher tolerance than non-Saccharomyces, 3 of them with the highest tolerance among all. Regarding the non-Saccharomyces yeasts, C. tropicalis JA2 and W. anomalus 740 appeared as the most tolerant, whereas Spathaspora strains appeared very sensitive to the different compounds.
Topics: Acids; Furaldehyde; Lignin; Microbial Viability; Phenols; Saccharomyces cerevisiae; Yeasts
PubMed: 33825150
DOI: 10.1007/s42770-021-00489-0 -
Journal of Microbiology and... Dec 2012Makgeolli is a traditional rice wine favored by the general public in Korea. This study investigated the fermentation and sensory characteristics of using wild yeast...
Makgeolli is a traditional rice wine favored by the general public in Korea. This study investigated the fermentation and sensory characteristics of using wild yeast strains for brewing makgeolli. A non-Saccharomyces cerevisiae strain was isolated from nuruk and termed Y197-13. It showed 98% similarity to Pichia anomala and had an optimal growth temperature of 25 degrees C. Makgeolli was manufactured using koji, jinju nuruk, and improved nuruk as fermentation agents. Y197-13 makgeolli brewed with koji had alcohol and solids contents of 11.1% and 13.9%, respectively. Sweet sensory characteristics were attributed to residual sugars in makgeolli with 6% alcohol. The makgeolli had a fresh sour taste and carbonated taste. Volatile component analysis showed the isoamyl alcohol, phenylethyl alcohol, isoamyl acetate, and fatty acid, including ethyl oleate and ethyl linoleate, relative peak area was higher in Y197-13 makgeolli than in makgeolli with Saccharomyces cerevisiae. These results suggest the wild yeast, Y197-13, as a candidate for brewing makgeolli.
Topics: Biotechnology; Culture Media; Feasibility Studies; Fermentation; Food Microbiology; Pichia; Volatile Organic Compounds; Wine
PubMed: 23221539
DOI: 10.4014/jmb.1210.10038 -
World Journal of Microbiology &... Nov 2022Yeast mannoproteins are proposed as a paraprobiotics with antimicrobial and prebiotic properties. They can be used as biopreservatives in food and in diseases therapies....
Yeast mannoproteins are proposed as a paraprobiotics with antimicrobial and prebiotic properties. They can be used as biopreservatives in food and in diseases therapies. The knowledge about the specificity and/or capability of their influence on the growth of different microorganism is limited. The study determined the effect of mannoprotein preparations of Saccharomyces cerevisiae (S. cerevisiae) ATCC 7090 and nonconventional yeast origin [Metschnikowia reukaufii (M. reukaufii) WLP 4650 and Wickerhamomyces anomalus (W. anomalus) CCY 38-1-13] on the growth of selected bacteria of the genera: Lactobacilllus, Limosilatobacillus, Limosilatobacillus, Bifidobacterium, Staphylococcus, Enterococcus, Pseudomonas, Escherichia, Proteus and Salmonella. The degree of stimulation or growth inhibition of tested bacteria depended on the type and dose of the mannoprotein and the bacterial strain. The addition of the tested preparations in the entire range of applied concentrations had a positive effect especially on the growth of Lactobacillus arabinosus ATCC 8014 and Bifidobacterium animalis subsp. lactis B12. Mannoproteins isolated from S. cerevisiae limited the growth of the Escherichia coli (E. coli) ATCC 25922, Pseudomonas aureoginosa (P. aureoginosa) ATCC 27853, Proteus mirabilis ATCC 35659 and Salmonella Enteritidis ATCC 13076 to the greatest extent, while preparations of M. reukaufii and W. anomalus origin most effectively limited the growth of Staphylococcus aureus strains, E. coli and P. aureoginosa. The growth of Enterococcus faecalis was stimulated by the presence of all studied preparations in most of the concentrations used. Further research will determine how the purification process of studied mannoproteins or oligosaccharide fractions, its structure and composition influence on the growth of selected bacteria and what is the mechanism of its activity.
Topics: Saccharomyces cerevisiae; Escherichia coli; Phylogeny; Anti-Infective Agents; Anti-Bacterial Agents; Bacteria; Microbial Sensitivity Tests
PubMed: 36319710
DOI: 10.1007/s11274-022-03448-5 -
Foods (Basel, Switzerland) Aug 2020The influence of fruit varieties on yeast ecology during spontaneous plum mash fermentation was investigated. Yeast colonies were isolated from mashes obtained from four...
The influence of fruit varieties on yeast ecology during spontaneous plum mash fermentation was investigated. Yeast colonies were isolated from mashes obtained from four plum varieties throughout fermentation in laboratory conditions during two consecutive years. The yeast strains were differentiated by random amplification of polymorphic DNA (RAPD-PCR) and identified by the 26S rDNA D1/D2 sequence analysis. , spp. and were the dominant yeasts during the early stages of plum mash fermentation, while the middle and end phases were dominated by . The strains of , , , and were also detected in fermenting plum mashes. sp. M1, H1 and H2 strains were detected in all samples, irrespective of the tested variety and year. Investigation of the impact of individual yeast strains on the production of volatile compounds showed the potential possibility of using them as starter cultures.
PubMed: 32759797
DOI: 10.3390/foods9081054 -
Frontiers in Physiology 2022Management of the rice brown planthopper Stål is challenging because it can rapidly adapt to new pesticides within several generations. Combined use of chemical...
Management of the rice brown planthopper Stål is challenging because it can rapidly adapt to new pesticides within several generations. Combined use of chemical insecticides and antimicrobials was proposed as an alternative strategy to control . Our previous experiments identified two effective agents (chemical insecticide: pymetrozine and antimicrobial: zhongshengmycin) that act on different targets in . However, conditions and effectiveness of combinations of antimicrobials and insecticides against are still unknown. Here, we evaluated separate and combined effects of pymetrozine and zhongshengmycin on third instar nymphs of under laboratory and greenhouse conditions. Results showed that zhongshengmycin exerts significant inhibitory effects on the three endosymbionts , , and cultured of . Combinations of pymetrozine and zhongshengmycin under laboratory conditions produced additive or synergistic effects on and caused higher mortality in third instar nymphs than either of them used alone. Experiments under greenhouse conditions further demonstrated that effective component quality ratio of pymetrozine to zhongshengmycin of 1:10 and 1:40 with co-toxicity coefficients of 221.63 and 672.87, respectively, also produced significant synergistic effects against . Our results indicated that chemical insecticides combined with antimicrobials may provide a potential novel strategy for controlling by inhibiting its endosymbionts.
PubMed: 35707007
DOI: 10.3389/fphys.2022.875610 -
Journal of Food Protection Sep 1993Populations and frequency of occurrence of yeasts in frozen apple, cherry, grape, orange, and pineapple juice concentrates were determined. Total yeast populations...
Populations and frequency of occurrence of yeasts in frozen apple, cherry, grape, orange, and pineapple juice concentrates were determined. Total yeast populations ranged from log < 1.00 to 5.41 CFU/ml of diluted (1:4) concentrate and increased to 2.42-7.34 CFU/ml after 24 h of incubation at 25°C. One hundred fifty-four isolates from 33 samples of fruit juice concentrates represented 21 species and 12 genera. The most frequently isolated species were Saccharomyces cerevisiae (24.7% of isolates), Candida stellata (22.1%), and Zygosaccharomyces rouxii (14.3%), followed by, in decreasing order of frequency, Torulaspora delbrueckii , Rhodotorula mucilaginosa , Issatchenkia orientalis , Hanseniaspora occidentalis , Lodderomyces elongisporus , Kluyveromyces thermotolerans , Hanseniaspora guilliermondii , Candida glabrata , and Pichia anomala , each representing 3-8% of isolates. Candida magnoliae , Candida maltosa , Candida parapsilosis , Candida tropicalis , Clavispora lusitaniae , Cryptococcus humicolus , C. laurentii , Pichia membranaefaciens , and Sporidiobolus salmonicolor were represented by single isolates. Populations in various samples consisted of 24-100% S. cerevisiae , 52-100% C. stellata , and 3-56% for Z. rouxii . S. cerevisiae and Z. rouxii were isolated, respectively, from five and four types of fruit concentrates investigated. This may be the first observation of this high frequency of C. stellata in juice concentrates.
PubMed: 31113051
DOI: 10.4315/0362-028X-56.9.777