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Journal, Genetic Engineering &... Sep 2022Fermented foods are the results of metabolic activities of various microorganisms. People have traditionally known how to culture desirable microorganisms, primarily...
BACKGROUND
Fermented foods are the results of metabolic activities of various microorganisms. People have traditionally known how to culture desirable microorganisms, primarily lactic acid bacteria, yeasts, and filamentous molds, for the manufacture of edible foods. Yeast isolated from home-made mango pickle from Hamirpur, Himachal Pradesh, was assessed for probiotic properties and their enzymatic profiling.
RESULTS
Four yeast isolates were isolated out of which P. kudriavzevii Y33 was selected on the basis of high acid tolerance as well as broadest antimicrobial activity. The selected isolate was observed to have high acid tolerance at pH 2 and show strong antimicrobial activity against all the pathogens examined. P. kudriavzevii Y33 can also withstand high bile concentration and showed high viability index, i.e., 95% at concentration of 2% of bile. The isolate was able to demonstrate high cholesterol assimilation in medium containing ox bile and taurocholate, at 88.58 and 86.83%, respectively. The autoaggregation ability of isolate increases with increasing the time of incubation and showed 87% of autoaggregation after 24 h of incubation. P. kudriavzevii Y33 exhibited resistance towards different antibiotics, found to be positive for exopolysaccharide production and showed no hemolytic activity. The isolate was observed to produce several enzymes such as β-galactosidase, protease, amylase, phytase, and lipase.
CONCLUSIONS
The results of the current study revealed that P. kudriavzevii Y33 has various beneficial qualities that suggest it could be used as probiotics. Enzymes produced by yeast isolate help in improving flavor and mineral availability in the fermented products.
PubMed: 36083419
DOI: 10.1186/s43141-022-00416-2 -
Frontiers in Microbiology 2022To explore the potential application of non- yeasts screened from Baijiu fermentation environment in winemaking, the effect of four Baijiu non- yeasts (two and two )...
To explore the potential application of non- yeasts screened from Baijiu fermentation environment in winemaking, the effect of four Baijiu non- yeasts (two and two ) sequentially fermented with on the physicochemical parameters and volatile compounds of wine was analyzed. The results indicated that there was no obvious antagonism between and or in sequential fermentations, and all strains could be detected at the end of alcoholic fermentation. Compare with pure fermentation, sequential fermentations significantly reduced higher alcohols, fatty acids, and ethyl esters and increased acetate esters; sequential fermentations reduced the contents of C6 alcohols, total higher alcohols, fatty acids, and ethyl esters and significantly increased the contents of acetate esters (especially ethyl acetate and 3-methylbutyl acetate). Sequential fermentation of Baijiu non- yeast and improved the flavor and quality of wine due to the higher ester content and lower concentration of higher alcohols and fatty acids, non- yeasts selected from Baijiu fermentation environment have potential applications in winemaking, which could provide a new strategy to improve wine flavor and quality.
PubMed: 35711782
DOI: 10.3389/fmicb.2022.902597 -
Journal of Fungi (Basel, Switzerland) Dec 2021Improving the comprehensive utilization of sugars in lignocellulosic biomass is a major challenge for enhancing the economic viability of lignocellulose biorefinement. A...
Improving the comprehensive utilization of sugars in lignocellulosic biomass is a major challenge for enhancing the economic viability of lignocellulose biorefinement. A robust yeast N-X showed excellent performance in ethanol production under high temperature and low pH conditions and was engineered for ᴅ-xylonate production without xylitol generation. The recombinant strain N-X/S1 was employed for sequential production of ᴅ-xylonate and ethanol from ᴅ-xylose, feeding on ᴅ-glucose without pH control in a two-stage strategy of aerobic and shifting micro-aerobic fermentation. Acid-pretreated corncob without detoxification and filtration was used for ᴅ-xylonate production, then simultaneous saccharification and ethanol fermentation was performed with cellulase added at pH 4.0 and at 40 °C. By this strategy, 33.5 g/L ᴅ-xylonate and 20.8 g/L ethanol were produced at yields of 1.10 g/g ᴅ-xylose and 84.3% of theoretical value, respectively. We propose a promising approach for the sequential production of ᴅ-xylonate and ethanol from non-detoxified corncob using a single microorganism.
PubMed: 34947020
DOI: 10.3390/jof7121038 -
Microorganisms Apr 2023There is an expanding market for beer of different flavors. This study aimed to prepare a craft Belgian-style pale ale with a non- yeast. 4A was used as a sole starter...
There is an expanding market for beer of different flavors. This study aimed to prepare a craft Belgian-style pale ale with a non- yeast. 4A was used as a sole starter culture, and malted barley as the only substrate. The ingredients and brewing process were carefully monitored to ensure the quality and innocuousness of the beverage. During fermentation, the yeast consumed 89.7% of total sugars and produced 13.8% / of ethanol. The product was fermented and then aged for 8 days, adjusted to 5% / alcohol, and analyzed. There were no traces of mycotoxins, lead, arsenic, methanol, or microbiological contamination that would compromise consumer health. According to the physicochemical analysis, the final ethanol concentration (5.2% /) and other characteristics complied with national and international guidelines. The ethyl acetate and isoamyl alcohol present are known to confer sweet and fruity flavors. The sensory test defined the beverage as refreshing and as having an apple and pear flavor, a banana aroma, and a good level of bitterness. The judges preferred it over a commercial reference sample of Belgian-style pale ale made from . Hence, 4A has the potential for use in the beer industry.
PubMed: 37110400
DOI: 10.3390/microorganisms11040977 -
Food Science and Biotechnology Apr 2021Co-fermentation using yeast ( and ) and the bacteria () as starters isolated from spontaneous sourdough was conducted for the brewing of glucuronic acid (GlcA)-enriched...
Co-fermentation using yeast ( and ) and the bacteria () as starters isolated from spontaneous sourdough was conducted for the brewing of glucuronic acid (GlcA)-enriched apple cider. The concentration of GlcA in the apple cider co-fermented for 14 d with commercial and was 37.7 ± 1.7 mg/mL while a concentration of 62.8 ± 3.1 mg/mL was recorded for fermentation with and , which was higher than the corresponding single yeast fermentation. The co-fermented apple cider revealed higher 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity of 171.67 ± 0.79 µg trolox equivalents (TE)/mL using and , compared to the control (143.89 ± 7.07 µg TE/mL) just using . Thus, the co-fermentation of and and and provided a new strategy for the development of GlcA-enriched apple cider with enhanced antioxidant capacity.
PubMed: 33936847
DOI: 10.1007/s10068-021-00883-2 -
Microbial Biotechnology May 2021The unconventional yeast Pichia kudriavzevii is renowned for its ability to survive at low pH and has been exploited for the industrial production of various organic...
The unconventional yeast Pichia kudriavzevii is renowned for its ability to survive at low pH and has been exploited for the industrial production of various organic acids, especially succinic acid (SA). However, P. kudriavzevii can also utilize the di- and tricarboxylate intermediates of the Krebs cycle as the sole carbon sources for cell growth, which may adversely affect the extracellular accumulation of SA. Because the carboxylic acid transport machinery of P. kudriavzevii remains poorly understood, here, we focused on studying its SA transportation process from the perspective of mining and characterization of dicarboxylate transporters in a newly isolated acid-tolerant P. kudriavzevii strain CY902. Through genome sequencing and transcriptome analysis, two JEN family carboxylate transporters (PkJEN2-1 and PkJEN2-2) were found to be involved in SA transport. Substrate specificity analysis revealed that both PkJEN proteins are active dicarboxylate transporters, that can effectively import succinate, fumarate and L-malate into the cell. In addition, PkJEN2-1 can transport α-ketoglutarate, while PkJEN2-2 cannot. Since PkJEN2-1 shows higher transcript abundance than PkJEN2-2, its role in dicarboxylate transport is more important than PkJEN2-2. In addition, PKJEN2-2 is also responsible for the uptake of citrate. To our best knowledge, this is the first study to show that a JEN2 subfamily transporter is involved in tricarboxylate transport in yeast. A combination of model-based structure analysis and rational mutagenesis further proved that amino acid residues 392-403 of the tenth transmembrane span (TMS-X) of PkJEN2-2 play an important role in determining the specificity of the tricarboxylate substrate. Moreover, these two PkJEN transporters only exhibited inward transport activity for SA, and simultaneous inactivation of both PkJEN transporters reduced the SA influx, resulting in enhanced extracellular accumulation of SA in the late stage of fermentation. This work provides useful information on the mechanism of di-/tricarboxylic acid utilization in P. kudriavzevii, which will help improve the organic acid production performance of this microbial chassis.
Topics: Membrane Transport Proteins; Pichia; Saccharomyces cerevisiae; Succinates; Succinic Acid
PubMed: 33629807
DOI: 10.1111/1751-7915.13781 -
Journal of Fungi (Basel, Switzerland) Oct 2022The aim of this study was to investigate the effects of purified β-glucosidases from SLY-4, F2-24, and HX-13 (named as SLY-4E, F2-24E, and HX-13E, respectively) on...
The aim of this study was to investigate the effects of purified β-glucosidases from SLY-4, F2-24, and HX-13 (named as SLY-4E, F2-24E, and HX-13E, respectively) on the flavor complexity and typicality of wines. Cabernet Sauvignon wines were fermented by with the addition of SLY-4E, F2-24E, and HX-13E; the fermentation process and characteristics of wines were analyzed. The addition of SLY-4E, F2-24E, and HX-13E into must improved the contents of terpenes, higher alcohols, and esters, and decreased the contents of C compounds and fatty acids, which enhanced the fruity, floral, and taste aspects, reducing the unpleasant green of wines with no significant difference in their appearance. β-glucosidases from different yeast species produced different aroma compound profiles which presented different flavor and quality. F2-24EW had the best effect on flavor and quality of wine followed by SLY-4EW and HX-13EW. These research results can provide references for the use of β-glucosidases from non- yeasts to improve the flavor complexity, typicality, and quality of wines.
PubMed: 36294622
DOI: 10.3390/jof8101057 -
Food Chemistry Feb 2021The use of starters during fermentation has been gaining momentum as it can warrant high-quality chocolate. The objective of this study was to investigate the influence...
The use of starters during fermentation has been gaining momentum as it can warrant high-quality chocolate. The objective of this study was to investigate the influence of Saccharomyces cerevisiae (Sc) and Pichia kudriavzevii (Pk) during on-farm fermentation on physico-chemical and microbiological characteristics and levels of methylxanthines and bioactive amines of cocoa. Four treatments were used: ScPk (1:1), only Sc, only Pk, and no starter (control). The starters lead to changes throughout fermentation, but provided fermented cocoa with similar pH, titratable acidity, reducing sugars and phenolic compounds. ScPk shortened fermentation time by 24 h. The ScPk fermented and dried cocoa had higher levels of monomeric phenols, methylxanthines, phenylethylamine and lower levels of the putrefactive amines - putrescine and cadaverine (p < 0.05). The results were confirmed by multivariate analysis. Based on these results, the mixture of both yeasts species is a promising starter for cocoa fermentation decreasing duration time and modulating high-quality components.
Topics: Amines; Cacao; Caffeine; Catechin; Chocolate; Farms; Fermentation; Food Microbiology; Hydrogen-Ion Concentration; Phenols; Pichia; Saccharomyces cerevisiae; Temperature; Theobromine; Theophylline; Time Factors
PubMed: 32810810
DOI: 10.1016/j.foodchem.2020.127834 -
Foods (Basel, Switzerland) Feb 2023This study explored the effect of the combination of yeast, non- yeast (), and during cider fermentation on physicochemical properties, antioxidant activities, flavor...
This study explored the effect of the combination of yeast, non- yeast (), and during cider fermentation on physicochemical properties, antioxidant activities, flavor and aroma compounds, as well as sensory qualities. Ciders fermented with the triple mixed-cultures of these three species showed lower acid and alcohol content than those fermented with the single-culture of . The antioxidant activities were enhanced by the triple mixed-culture fermentation, giving a higher 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging rate and total antioxidant capacity; specifically, the SPL5 cider showed the highest DPPH radical scavenging rate (77.28%), while the SPL2 gave the highest total antioxidant capacity (39.57 mmol/L). Additionally, the triple mixed-culture fermentation resulted in improved flavor and aroma with a lower acidity (L-malic acid) and higher aroma compounds (Esters), when compared with the single-culture fermented ciders (); more specifically, the SPL4 cider resulted in the highest total flavor and aroma compounds. In addition, sensory evaluation demonstrated that ciders produced using the triple mixed-cultures gained higher scores than those fermented using the single-culture of , giving better floral aroma, fruity flavor, and overall acceptability. Therefore, our results indicated that the triple mixed-cultures (, , and ) were found to make up some enological shortages of the single fermented cider. This study is believed to provide a potential strategy to enhance cider quality and further give a reference for new industrial development protocols for cider fermentation that have better sensory qualities with higher antioxidant properties.
PubMed: 36766182
DOI: 10.3390/foods12030655 -
Frontiers in Microbiology 2021Non- yeast with -glucosidase activity might positively contribute to the flavor and quality of wines. The contribution of four non- yeast strains SLY-4, F2-24, F2-16,...
Non- yeast with -glucosidase activity might positively contribute to the flavor and quality of wines. The contribution of four non- yeast strains SLY-4, F2-24, F2-16, and HX-13 with -glucosidase activity to the flavor and quality of wine making was studied. Compared with those of single fermentation, the four non- yeast strains could grow and consume sugar completely with longer fermentation periods, and with no significantly negative effect on chemical characteristics of wines. Moreover, they produced lower content of C compounds, benzene derivative, and fatty acid ethyl ester compounds and higher content of terpene, -ionone, higher alcohol, and acetate compounds. Different yeast strains produced different aroma compounds profiles. In general, the sensory evaluation score of adding non- yeast-fermented wine was better than that of , and SLY-4 fermentation received the highest one, followed by F2-24, F2-16, and HX-13 from high to low. The research results provide a theoretical basis for the breeding of non- yeast and its application in wine making.
PubMed: 34539588
DOI: 10.3389/fmicb.2021.626920