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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 -
Antimicrobial Agents and Chemotherapy May 2021Invasive yeast infections represent a major global public health issue, and only few antifungal agents are available. Azoles are one of the classes of antifungals used...
Invasive yeast infections represent a major global public health issue, and only few antifungal agents are available. Azoles are one of the classes of antifungals used for treatment of invasive candidiasis. The determination of antifungal susceptibility profiles using standardized methods is important to identify resistant isolates and to uncover the potential emergence of intrinsically resistant species. Here, we report data on 9,319 clinical isolates belonging to 40 pathogenic yeast species recovered in France over 17 years. The antifungal susceptibility profiles were all determined at the National Reference Center for Invasive Mycoses and Antifungals based on the EUCAST broth microdilution method. The centralized collection and analysis allowed us to describe the trends of azole susceptibility of isolates belonging to common species, confirming the high susceptibility for ( = 3,295), ( = 641), and ( = 820) and decreased susceptibility for ( = 1,274) and ( = 343). These profiles also provide interesting data concerning azole susceptibility of species complex, showing comparable MIC distributions for the three species but lower MICs and MICs for serotype D ( = 208) compared to serotype A ( = 949) and AD hybrids ( = 177). Finally, these data provide useful information for rare and/or emerging species, such as ( = 221), ( = 184), complex ( = 150), complex ( = 87), ( = 55), and ( = 36).
Topics: Antifungal Agents; Azoles; Drug Resistance, Fungal; France; Microbial Sensitivity Tests; Pichia; Rhodotorula; Saccharomycetales
PubMed: 33820766
DOI: 10.1128/AAC.02615-20 -
Molecules (Basel, Switzerland) Mar 2021Olive mill wastewater (OMW) contains valuable and interesting bioactive compounds, among which is hydroxytyrosol, which is characterized by a remarkable antioxidant...
Olive mill wastewater (OMW) contains valuable and interesting bioactive compounds, among which is hydroxytyrosol, which is characterized by a remarkable antioxidant activity. Due to the health claims related to olive polyphenols, the aim of this study was to obtain an extract from OMW with an increased level of hydroxytyrosol by means of microbial enzymatic activity. For this purpose, four commercial adsorbent resins were selected and tested. The beta-glucosidase and esterase activity of strains of , and were also investigated and compared to those of a commercial enzyme and an strain. The strain showed the best enzymatic performances. The SP207 resin showed the best efficiency in selective recovery of hydroxytyrosol, tyrosol, oleuropein, and total phenols. The bioconversion test of the OMW extract was assessed by using both culture broths and pellets of the tested strains. The results demonstrated that the pellets of and were the most effective in hydroxytyrosol increasing in phenolic extract. The interesting results suggest the possibility to study new formulations of OMW phenolic extracts with multifunctional microorganisms.
Topics: Fungi; Lactobacillaceae; Olea; Phenols; Plant Extracts; Probiotics; Waste Disposal, Fluid; beta-Glucosidase
PubMed: 33808362
DOI: 10.3390/molecules26071944 -
Microorganisms Mar 2021The aim of the present study was to assess the technological and safety potential of 207 lactic acid bacteria (LAB) and 195 yeast strains isolated from spontaneously...
The aim of the present study was to assess the technological and safety potential of 207 lactic acid bacteria (LAB) and 195 yeast strains isolated from spontaneously fermented Greek wheat sourdoughs. More accurately, the amylolytic, proteolytic, lipolytic, phytase and amino acid decarboxylase activities, along with the production of exopolysaccharides and antimicrobial compounds by the LAB and yeast isolates, were assessed. A well diffusion assay revealed seven proteolytic LAB and eight yeast strains; hydrolysis of tributyrin was evident only in 11 LAB strains. A further Sodium Dodecyl Sulphate-Polyacrylamide Gel Electrophoresis (SDS-PAGE) indicated partial hydrolysis of gluten. Lipolysis kinetics over 21 days was applied, exhibiting that lipolytic activity ranged from 6.25 to 65.50 AU/mL. Thirteen LAB inhibited and growth and 12 yeast strains inhibited growth. Twenty-one strains exhibited inhibitory activity against , as well as several sourdough-associated isolates. The structural gene encoding plantaricin 423 was detected in 19 strains, while the structural genes encoding plantaricins NC8, PlnE/F, PlnJ/K, and S were detected in two strains. None of the microbial strains tested exhibited exopolysaccharide (EPS) production, amino acid decarboxylase, amylolytic or phytase activity. The technological and safety potential of the and strains was highlighted, since some of them exhibited proteolytic, lipolytic, antibacterial and antimould activities.
PubMed: 33805132
DOI: 10.3390/microorganisms9040671 -
Engineering in Life Sciences Mar 2021Ethyl acetate is currently produced from fossil carbon resources. This ester could also be microbially synthesized from sugar-rich wastes of the food industry. Wild-type...
Ethyl acetate is currently produced from fossil carbon resources. This ester could also be microbially synthesized from sugar-rich wastes of the food industry. Wild-type strains with GRAS status are preferred for such applications. Production of ethyl acetate by wild-type yeasts has been repeatedly reported, but comparative studies with several strains at various induction modes are largely missing. Here, synthesis of ethyl acetate by three yeasts with GRAS status, DSM 5422, DSM 2361 and DSM 6766, was studied under identical and well-defined conditions in an aerated bioreactor, by inducing the ester synthesis via iron or oxygen limitation. Balancing the ester synthesis was based on measured concentrations of ethyl acetate in the exhaust gas, delivering masses of synthesized ester and synthesis rates in a high temporal resolution. All tested yeasts synthesized ethyl acetate under these conditions, but the intensity varied with the strain and induction mode. The highest yields were achieved under iron limitation with (0.182 g g) and under oxygen limitation with (0.053 g g). Iron limitation proved to be the better inducer for ester synthesis while oxygen limitation favored ethanol formation. DSM 5422 was the most potent producer of ethyl acetate exhibiting the highest biomass-specific synthesis rate of 0.5 g gh under moderate iron limitation.
PubMed: 33716614
DOI: 10.1002/elsc.202000048 -
Scientific Reports Feb 2021Yeasts are becoming popular as novel ingredients in fish feeds because of their potential to support better growth and concomitantly ensure good fish health. Here, three...
Yeasts are becoming popular as novel ingredients in fish feeds because of their potential to support better growth and concomitantly ensure good fish health. Here, three species of yeasts (Cyberlindnera jadinii, Blastobotrys adeninivorans and Wickerhamomyces anomalus), grown on wood sugars and hydrolysates of chicken were subjected to two down-stream processes, either direct heat-inactivation or autolysis, and the feed potential of the resulting yeast preparations was assessed through a feeding trial with Atlantic salmon fry. Histological examination of distal intestine based on widening of lamina propria, showed that autolyzed W. anomalus was effective in alleviating mild intestinal enteritis, while only limited effects were observed for other yeasts. Our results showed that the functionality of yeast in counteracting intestinal enteritis in Atlantic salmon was dependent on both the type of yeast and the down-stream processing method, and demonstrated that C. jadinii and W. anomalus have promising effects on gut health of Atlantic salmon.
Topics: Animal Feed; Animals; Aquaculture; Chickens; Enteritis; Intestinal Mucosa; Salmo salar; Yeasts
PubMed: 33627754
DOI: 10.1038/s41598-021-83764-2 -
Frontiers in Microbiology 2020The ascomycete yeast is a mutualistic symbiont of different insects, including diptera vectors of diseases. Although fungal symbioses have been so far poorly... (Review)
Review
The ascomycete yeast is a mutualistic symbiont of different insects, including diptera vectors of diseases. Although fungal symbioses have been so far poorly characterized, the topic is gaining attention as yeast-insect interactions can provide pivotal information on insect biology, such as their environmental adaptation or vectorial capability. We review the symbiosis between and mosquitoes, which implies nutritional and protective functions. Furthermore, we focus on antiplasmodial effects of in malaria vectors and discuss the yeast potential for the "symbiotic control" (SC) of mosquito-borne diseases (MBDs).
PubMed: 33552032
DOI: 10.3389/fmicb.2020.621605 -
Frontiers in Microbiology 2020Dry fermented sausage is popular among the world because of its rich nutrition and unique flavor. Starter cultures play an important role in the quality of dry fermented...
Dry fermented sausage is popular among the world because of its rich nutrition and unique flavor. Starter cultures play an important role in the quality of dry fermented sausage. In this study, probiotics lactic acid bacteria N102, H1-5, Y4-1, and Y12-3 were isolated from food-borne materials. The physicochemical properties, microbial populations, TBARS, lipolysis, proteolysis, and volatile flavor compounds of dry fermented sausages with different starter cultures were evaluated comparatively during the ripening process. The results showed that both N102 and H1-5 grow well and could rapidly reduce the pH value of the products. At the same time, they could significantly reduce the number of , so as to ensure the safety of the products. In addition, the strains N102 promoted the formation of flavor compounds 2,3-butanedione, 3-hydroxy-2-butanone, and carnosine, whereas taurine content of batch H1-5 was significantly increased, while yeast y4-1 and y12-3 could also grow faster in sausage and promoted the esters and alcohols formation such as ethyl acetate and linalool, with the formation of γ-aminobutyric acid by y4-1. Compared with lactic acid bacteria, yeasts showed to contribute more in flavor formation and effective inhibition of lipid oxidation. The starter cultures played different roles in flavor contribution and had obvious differentiation in the ripening process of dry fermented sausage.
PubMed: 33488553
DOI: 10.3389/fmicb.2020.611260 -
Food Science & Nutrition Jan 2021Microorganism species and inoculation fermentation methods have great influence on physicochemical and flavor properties of rice wine. Thus, this work investigated...
Microorganism species and inoculation fermentation methods have great influence on physicochemical and flavor properties of rice wine. Thus, this work investigated microbial interactions and physicochemical and aroma changes of rice wine through different inoculation strategies of and (. The results underlined that inoculation strategies and yeasts all affected the volatile acidity, total acidity, and alcohol content of rice wine. The sequential cofermentation consumed relatively more sugar and resulted in the higher ethanol content, causing reduced thiols and increased alcohols, esters, phenylethyls, and terpenes, which was more conducive to improve rice wine flavor than simultaneous cofermentation. Moreover, simultaneous cofermentation increased fatty aroma of rice wine, while sequential cofermentation increased mellow and cereal-like flavor. These results confirmed that sequential cofermentation of and was a choice for the future production of rice wine with good flavor and quality.
PubMed: 33473272
DOI: 10.1002/fsn3.1899 -
The Journal of International Medical... Jan 2021is a rare fungal cause of neonatal sepsis. Premature and very low birthweight infants are at especially high risk of neonatal fungal infections. There have been no...
is a rare fungal cause of neonatal sepsis. Premature and very low birthweight infants are at especially high risk of neonatal fungal infections. There have been no reports of infection in Anhui Province, China. Here, we report a case of fungemia in a newborn boy admitted 30 minutes after delivery with grunting, cyanosis, and asphyxia. was identified as the causative organism using blood culture, DNA sequencing, and mass spectrometric analysis. After 20 days of fluconazole therapy, the patient's symptoms stabilized. Together with other relevant literature, this report provides evidence that premature neonates are at increased risk of fungal infections and that fungemia should be diagnosed early using blood cultures to enable effective treatment. Fluconazole may be effective for treating neonates with infection.
Topics: Antifungal Agents; Candida; Candidiasis; China; Humans; Infant; Infant, Newborn; Male; Saccharomycetales; Sepsis
PubMed: 33472484
DOI: 10.1177/0300060520982804