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Journal of Fungi (Basel, Switzerland) Nov 2022Yeast strains are widely used in ruminant production. However, knowledge about the effects of rumen native yeasts on ruminants is limited. Therefore, this study aimed to...
Isolation and Characterization of Ruminal Yeast Strain with Probiotic Potential and Its Effects on Growth Performance, Nutrients Digestibility, Rumen Fermentation and Microbiota of Hu Sheep.
Yeast strains are widely used in ruminant production. However, knowledge about the effects of rumen native yeasts on ruminants is limited. Therefore, this study aimed to obtain a rumen native yeast isolate and investigate its effects on growth performance, nutrient digestibility, rumen fermentation and microbiota in Hu sheep. Yeasts were isolated by picking up colonies from agar plates, and identified by sequencing the ITS sequences. One isolate belonging to had the highest optical density among these isolates obtained. This isolate was prepared to perform an animal feeding trial. A randomized block design was used for the animal trial. Sixteen Hu sheep were randomly assigned to the control (CON, fed basal diet, = 8) and treatment group (LPK, fed basal diet plus , CFU = 8 × 10 head/d, = 8). Sheep were housed individually and treated for 4 weeks. Compared to CON, LPK increased final body weight, nutrient digestibility and rumen acetate concentration and acetate-to-propionate ratio in sheep. The results of Illumina MiSeq PE 300 sequencing showed that LPK increased the relative abundance of lipolytic bacteria ( spp. and spp.) and probiotic bacteria ( spp. and spp.). For rumen eukaryotes, LPK increased the genera associated with fiber degradation, including protozoan and fungus . Our results discovered that rumen native yeast isolate might promote the digestion of fibers and lipids by modulating specific microbial populations with enhancing acetate-type fermentation.
PubMed: 36547593
DOI: 10.3390/jof8121260 -
PLoS Pathogens May 2023The pathogenic yeast Pichia kudriavzevii, previously known as Candida krusei, is more distantly related to Candida albicans than clinically relevant CTG-clade Candida...
The pathogenic yeast Pichia kudriavzevii, previously known as Candida krusei, is more distantly related to Candida albicans than clinically relevant CTG-clade Candida species. Its cell wall, a dynamic organelle that is the first point of interaction between pathogen and host, is relatively understudied, and its wall proteome remains unidentified to date. Here, we present an integrated study of the cell wall in P. kudriavzevii. Our comparative genomic studies and experimental data indicate that the general structure of the cell wall in P. kudriavzevii is similar to Saccharomyces cerevisiae and C. albicans and is comprised of β-1,3-glucan, β-1,6-glucan, chitin, and mannoproteins. However, some pronounced differences with C. albicans walls were observed, for instance, higher mannan and protein levels and altered protein mannosylation patterns. Further, despite absence of proteins with high sequence similarity to Candida adhesins, protein structure modeling identified eleven proteins related to flocculins/adhesins in S. cerevisiae or C. albicans. To obtain a proteomic comparison of biofilm and planktonic cells, P. kudriavzevii cells were grown to exponential phase and in static 24-h cultures. Interestingly, the 24-h static cultures of P. kudriavzevii yielded formation of floating biofilm (flor) rather than adherence to polystyrene at the bottom. The proteomic analysis of both conditions identified a total of 33 cell wall proteins. In line with a possible role in flor formation, increased abundance of flocculins, in particular Flo110, was observed in the floating biofilm compared to exponential cells. This study is the first to provide a detailed description of the cell wall in P. kudriavzevii including its cell wall proteome, and paves the way for further investigations on the importance of flor formation and flocculins in the pathogenesis of P. kudriavzevii.
Topics: Saccharomyces cerevisiae; Proteome; Proteomics; Candida albicans; Candida; Biofilms; Genomics; Cell Wall
PubMed: 37196016
DOI: 10.1371/journal.ppat.1011158 -
Indian Journal of Microbiology Dec 2020The search for promising yeasts that surpass the fermentative capacity of commercial strains, such as CAT-1, is of great importance for industrial ethanol processes in...
The search for promising yeasts that surpass the fermentative capacity of commercial strains, such as CAT-1, is of great importance for industrial ethanol processes in the world. Two yeasts, BB2 and BB9, were evaluated in comparison to the industrial yeast CAT-1. The objective was to evaluate the performance profile of the three studied strains in terms of growth, substrate consumption, and metabolite formation, aiming to determine their behaviour in different media and pH conditions. The results showed that under cultivation conditions simulating the medium used in the industrial process (must at 22° Brix at pH 3.0) the highest ethanol productivity was 0.41 g L h for CAT-1, compared to 0.11 g L h and 0.16 g L h for and BB2, respectively. CAT-1 produced three times more ethanol in must at pH 3.0 (28.30 g L) and in mineral medium at pH 3.0 (29.17 g L) and 5.0 (30.70 g L) when compared to the value obtained in sugarcane must pH 3.0 (9.89 g L). It was concluded that CAT-1 was not limited by the variation in pH in the mineral medium due to its nutritional composition, guaranteeing better performance of the yeast even in the presence of stressors. Only CAT-1 expressed he constitutive invertase enzyme, which is responsible for hydrolysing the sucrose contained in the must.
PubMed: 33087999
DOI: 10.1007/s12088-020-00891-6 -
3 Biotech Sep 2023This study aimed to isolate and characterize potential probiotic yeasts from Ethiopian injera sourdough and the study was conducted by collecting samples from Gondar and...
This study aimed to isolate and characterize potential probiotic yeasts from Ethiopian injera sourdough and the study was conducted by collecting samples from Gondar and Bahir Dar cities, Ethiopia. The potential yeasts were isolated and identified using morphological, physiological, biochemical and molecular based analysis. Promising isolates were selected to further investigate their in vitro probiotic properties, including survival at different temperatures (25, 30, 37, and 42 °C), acidic pH (2, 3, 4 and 5), bile salt (0.1, 0.3, and 0.5%), and osmotolerance (20, 30, 40, and 50% glucose concentration), antimicrobial activities, proteolytic and lipolytic activities as well as resistance to four antibiotics. From 20 samples, 38 isolates were obtained. Among these, 10 produced low or non-hydrogen sulfide and were selected for further work. Further screening tests revealed that five isolates (G1N1, G2N4, G3N1, G8N1, and B6N3) were able tolerate and grow at 37 °C, with harsh conditions of the human digestive tract like low pH, bile salt, and higher osmotic effect. The maximum growth OD values were recorded at 37 °C by isolate G4N1 (OD value (0.6667), while G3N1 exhibited a maximum growth OD value of 0.4227 at pH 2. On the other hand, G2N4 gave a maximum OD value of 0.8800 at 0.3% bile salt concentration. The promising isolates were sequenced and identified to species level. Based on phylogenetic tree analysis, all the five probiotic yeast isolates had one common ancestor and belonging to (G1N1 and G2N4), (G3N1 and B6N3), and (G8N1). This study revealed that Ethiopian injera sourdough could be potential source of different probiotic yeast strains. Strong emphasis should be given about the use of probiotic yeasts that are isolated from Ethiopian fermented foods.
PubMed: 37581092
DOI: 10.1007/s13205-023-03729-2 -
Food Chemistry May 2023Pichia kudriavzevii was one of the important aroma-producing fungi in the solid-state fermentation of Baijiu, and immobilization was an effective strategy for improving...
Pichia kudriavzevii was one of the important aroma-producing fungi in the solid-state fermentation of Baijiu, and immobilization was an effective strategy for improving microbial performance. Herein, P. kudriavzevii cells were immobilized in a gel network that crosslinked by chitosan and sodium alginate to form sodium alginate/chitosan-P. kudriavzevii microspheres (SA/CS-PMs). Their structural characteristics and formation processes were characterized by SEM and FT-IR. The effect of synthesis conditions on the performance of microspheres were determined by single-factor experiments. Under the optimal conditions, the SA/CS-PMs could increase the amylase activity of the fermentation broth by 57.18%, the esterase activity by 66.13%, the content of ester by 67.04%, and could be reused at least three times. Further research results indicated that the content of ester could be increased significantly in Baijiu solid-state fermentation with the SA/CS-PMs. In conclusion, the SA/CS-PMs could improve the ester production ability of P. kudriavzevii by increasing the esterase activity, which was a valuable exploration of directional biosynthesis and a feasible strategy to improve solid-state fermentation quality.
Topics: Fermentation; Chitosan; Alginates; Esters; Microspheres; Spectroscopy, Fourier Transform Infrared; Pichia; Esterases
PubMed: 36502727
DOI: 10.1016/j.foodchem.2022.135154 -
Food Science & Nutrition Aug 2023Soybean paste was a traditional fermented product in northeast China, mainly fermented by molds, yeast, , and lactic acid bacteria. In this study, the safety and...
Soybean paste was a traditional fermented product in northeast China, mainly fermented by molds, yeast, , and lactic acid bacteria. In this study, the safety and fermentation ability of lactic acid bacteria and yeast strains isolated from traditional soybean paste in northeast China were evaluated, and the dynamic changes of biogenic amines, aflatoxin, total acids, amino acid nitrogen, and volatile compounds were investigated during the fermentation of the traditional soybean paste. Among the tested strains, DPUL-J8 could decompose putrescine by 100%, and no biogenic amine was produced by DPUY-J8. DPUL-J8 and DPUY-J8 with strong biogenic amine degrading capacities were inoculated into the soybean paste. After 30 days of fermentation, the content of biogenic amines and aflatoxin in the fermented soybean paste declined by more than 60% and 50%, respectively. At the same time, compared with the control group without inoculation, the contents of total acid (1.29 ± 0.05 g/100 g), amino acid nitrogen (0.82 ± 0.01 g/100 g), and volatile compounds in soybean paste fermented by DPUL-J8 and DPUY-J8 were significantly increased, which had a good flavor. These results indicated that the use of DPUL-J8 and DPUY-J8 as starter cultures for soybean paste might be a good strategy to improve the safety and flavor of traditional Chinese soybean paste.
PubMed: 37576040
DOI: 10.1002/fsn3.3372 -
Journal of Dairy Science Nov 2022Indigenous microorganisms are important components of the complex ecosystem of many dairy foods including cheeses, and they are potential contributors to the development...
Indigenous microorganisms are important components of the complex ecosystem of many dairy foods including cheeses, and they are potential contributors to the development of a specific cheese's sensory properties. Among these indigenous microorganisms are the yeasts Cyberlindnera jadinii, Pichia kudriavzevii, and Kazachstania servazzii, which were previously detected using traditional microbiological methods in both raw milk and some artisanal specialty cheeses produced in the province of Québec, Canada. However, their levels across different cheese varieties are unknown. A highly specific and sensitive real-time quantitative PCR assay was developed to quantitate these yeast species in a variety of specialty cheeses (bloomy-rind, washed-rind, and natural-rind cheeses from raw, thermized, and pasteurized milks). The specificity of the quantitative PCR assay was validated, and it showed no cross-amplification with 11 other fungal microorganisms usually found in bloomy-rind and washed-rind cheeses. Cyberlindnera jadinii and P. kudriavzevii were found in the majority of the cheeses analyzed (25 of 29 and 24 of 29 cheeses, respectively) in concentrations up to 10 to 10 gene copies/g in the cheese cores, which are considered oxygen-poor environments, and 10 to 10 gene copies/cm in the rind. However, their high abundance was not observed in the same samples. Whereas C. jadinii was present and dominant in all core and rind samples, P. kudriavzevii was mostly present in cheese cores. In contrast, K. servazzii was present in the rinds of only 2 cheeses, in concentrations ranging from 10 to 10 gene copies/cm, and in 1 cheese core at 10 gene copies/g. Thus, in the ecosystems of specialty cheeses, indigenous yeasts are highly frequent but variable, with certain species selectively present in specific varieties. These results shed light on some indigenous yeasts that establish during the ripening of specialty cheeses.
Topics: Animals; Cheese; Ecosystem; Phylogeny; Oxygen; Polymerase Chain Reaction; Milk
PubMed: 36114057
DOI: 10.3168/jds.2022-21949 -
International Journal of Food... Oct 2019Ishizuchi-kurocha is a Japanese traditional fermented tea that is produced by primary aerobic and secondary fermentation steps. The secondary fermentation step of...
Culture-based analysis of fungi in leaves after the primary and secondary fermentation processes during Ishizuchi-kurocha production and lactate assimilation of P. kudriavzevii.
Ishizuchi-kurocha is a Japanese traditional fermented tea that is produced by primary aerobic and secondary fermentation steps. The secondary fermentation step of Ishizuchi-kurocha is mainly mediated through lactic acid bacteria. Here, we performed quantitative analyses of the culturable fungal communities at each step and identified several morphologically representative fungal isolates. While filamentous fungi (median, 3.2 × 10 CFU/g sample) and yeasts (median, 3.7 × 10 CFU/g) were both detected after the primary fermentation step, only yeasts (median, 1.6 × 10 CFU/g) were detected in the end of the secondary fermentation step, suggesting that the fungal community in tea leaves are dramatically changed between the two steps. Pichia kudriavzevii and Pichia manshurica, the prevalent fungal species at the end of the secondary fermentation step, grew well in exudate from the secondary fermentation step. P. kudriavzevii also grew well in media containing d- or l-lactate as the sole carbon source. The growth of the disruptant of cyb2A encoding a cytochrome b lactate dehydrogenase in P. kudriavzevii was severely impaired on medium supplemented with l-lactate, but not d-lactate, suggesting that Cyb2Ap plays a crucial role in the use of l-lactate, and P. kudriavzevii efficiently uses both l- and d-lactate as carbon sources. Thus, lactate assimilation seems to be a key phenotype to become a prevalent species in the secondary fermentation step, and Cyb2Ap has a pivotal role in l-lactate metabolism in P. kudriavzevii. Further understanding and engineering of P. kudriavzevii and P. manshurica will contribute to the control of lactic acid bacteria fermentation during the fermented tea production and also to other industrial uses.
Topics: Bioreactors; Candida; Fermentation; Fermented Foods; L-Lactate Dehydrogenase (Cytochrome); Lactic Acid; Pichia; Yeasts
PubMed: 31306941
DOI: 10.1016/j.ijfoodmicro.2019.108263 -
Journal of Basic Microbiology Jul 2016Application of growing microorganisms for cadmium removal is limited by the sensitivity of living cells to cadmium. The effects of sodium chloride (NaCl) preincubation...
Application of growing microorganisms for cadmium removal is limited by the sensitivity of living cells to cadmium. The effects of sodium chloride (NaCl) preincubation on the cadmium bioaccumulation and tolerance of Pichia kudriavzevii and Saccharomyces cerevisiae were investigated in this study. NaCl preincubation significantly reduced the intracellular and cell-surface cadmium bioaccumulation of P. kudriavzevii at both 6 and 20 mg L(-1) cadmium, while no obvious effect was observed in S. cerevisiae except that the intracellular cadmium bioaccumulation at 20 mg L(-1) cadmium was reduced obviously by 20-60 g L(-1) NaCl. For both yeasts, the improved contents of protein and proline after NaCl preincubation contributed to the cadmium tolerance. The thiol contents in P. kudriavzevii under cadmium stress were alleviated by NaCl preincubation, which might be due to the decrease of intracellular cadmium bioaccumulation. NaCl preincubation enhanced the contents of glycerol and trehalose in P. kudriavzevii under cadmium stress, while no acceleration was observed in S. cerevisiae. The results suggested that NaCl preincubation could be applied in cadmium removal by growing P. kudriavzevii to increase the cadmium tolerance of the yeast.
Topics: Biodegradation, Environmental; Cadmium; Drug Tolerance; Glycerol; Heavy Metal Poisoning; Pichia; Poisoning; Saccharomyces cerevisiae; Sodium Chloride; Stress, Physiological; Trehalose
PubMed: 26753521
DOI: 10.1002/jobm.201500555 -
Yeast (Chichester, England) Aug 2016The present research was undertaken to study the probiotic characteristics of Pichia kudriavzevii isolated from frozen idli batter. Polymerase chain reaction...
The present research was undertaken to study the probiotic characteristics of Pichia kudriavzevii isolated from frozen idli batter. Polymerase chain reaction amplification with 18S rRNA primers confirmed Pichia kudriavzevii, a xylose-utilizing probiotic strain. It was resistant to physiological concentrations of bile salts, pepsin and pancreatic enzyme. It also showed efficient auto-aggregation as well as co-aggregation ability with four commercial probiotic yeasts and exhibited good hydrophobicity in xylene and toluene. The strain inhibited the growth of 13 enteropathogens and showed a commensal relationship with four commercial probiotic yeast and bacteria. Moreover, it was resistant to 30 antibiotics with different modes of action. The yeast exhibited thermotolerance up to 95 °C for 2 h. The cell-free supernatants were also found to be heat stable, indicating the presence of thermostable secondary metabolites. Hence it could be exploited as starter culture, co-culture or probiotic in the preparation of fermented products or incorporated in heatable foods as well. Copyright © 2016 John Wiley & Sons, Ltd.
Topics: Anti-Bacterial Agents; Antibiosis; Bile Acids and Salts; Coculture Techniques; Drug Resistance, Microbial; Fermentation; Food Microbiology; Hot Temperature; Hydrogen-Ion Concentration; Hydrophobic and Hydrophilic Interactions; Microbial Viability; Phenotype; Pichia; Probiotics; Xylose
PubMed: 27370793
DOI: 10.1002/yea.3181