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Journal of Dairy Science Apr 2022The yeasts involved in the ripening process of artisanal soft raw ewe milk Protected Designation of Origin (PDO) Torta del Casar and Queso de la Serena cheeses produced...
The yeasts involved in the ripening process of artisanal soft raw ewe milk Protected Designation of Origin (PDO) Torta del Casar and Queso de la Serena cheeses produced in Extremadura, Spain, were isolated throughout their ripening process, strain typed, and characterized for some important technological properties. A total of 508 yeast isolates were obtained and identified by inter-single sequence repeat anchored PCR amplification analysis and subsequent sequencing of the internal transcribed spacer ITS1/ITS2 5.8S rRNA. A total of 19 yeast species representing 8 genera were identified. Debaryomyces hansenii, Pichia kudriavzevii, Kluyveromyces lactis, and Yarrowia lipolytica were the predominant species. We selected 157 isolates, by genotyping and origin, for technological characterization. The evaluation of yeast isolates' growth under stress conditions of cheese ripening showed that 87 presented better performance. Among them, 71 isolates were not able to catabolize tyrosine to produce a brown pigment. Principal component analysis of the biochemical features of these isolates showed that 9 strains stood out, 3 K. lactis strains (2287, 2725, and 1507), 2 Pichia jadinii (1731 and 433), 2 Yarrowia alimentaria (1204 and 2150), Y. lipolytica 2495 and P. kudriavzevii 373. These strains displayed strong extracellular proteolytic activity on skim milk agar as well as an adequate enzymatic profile (strong aminopeptidase and weak protease activity), suggesting their great potential for cheese proteolysis. Extracellular lipolytic activity was mainly restricted to Yarrowia spp. isolates and weakly present in P. kudriavzevii 373 and K. lactis 2725, although enzymatic characterization by API-ZYM (bioMérieux SA) evidenced that all may contribute, at least in part, to the lipolysis process. Moreover, these strains were able to assimilate lactose, galactose, and glucose at NaCl concentrations higher than that usually found in cheese. However, lactate and citrate assimilation were limited to Y. lipolytica 2495, P. kudriavzevii 373, and P. jadinii 433, and may contribute to the alkalinizing process relevant to biochemical processes that take place in the last stages of ripening. By contrast, K. lactis strains showed acidifying capacity and β-galactosidase activity and may take part in the initial stages of ripening, together with lactic acid bacteria. Thus, considering the technological characteristics studied, the 9 selected strains presented biochemical features well suited to their potential use as adjunct cultures, alone or in combination with autochthonous starter bacteria in the cheesemaking process, to overcome the heterogeneity of these PDO cheeses, preserving their unique sensory characteristics.
Topics: Animals; Candida; Cheese; Food Microbiology; Milk; Sheep; Yeasts
PubMed: 35123784
DOI: 10.3168/jds.2021-21368 -
Foods (Basel, Switzerland) Oct 2022Viticulture is one of the traditional industries in Slovakia, where there are six wine-growing regions: Malokarpatska, Southern Slovakia, Central Slovakia, Nitra,...
Viticulture is one of the traditional industries in Slovakia, where there are six wine-growing regions: Malokarpatska, Southern Slovakia, Central Slovakia, Nitra, Eastern Slovakia, and Tokaj. This study focuses on the detection of microbiota in soil samples, grape leaves and berries, and samples taken from fermenting must and young wine (the variety Tramín červený) in relation to the detected concentrations of biogenic amines during the fermentation process. In the examined samples, the number of yeasts and molds (from 3.8 to 6.8 log cfu/g or mL) and TVC (from 3.7 to 6.5 log cfu/g or mL) were determined via culture examination. At the same time, the number of LAB (from ˂3.0 to 4.4 log cfu/g or mL) was determined, which was the highest on day 4 of the must fermentation process and was related to the detected of the highest concentration of biogenic amines (histamine and tyramine) on day 6 in the investigated must samples using the UHPLC system. Mycobiota species were identified by MALDI-TOF MS, PCR, ITS-PCR-RFLP, and PCR sequencing of the amplified products. The study confirmed the presence of the yeasts . At the same time, the presence of molds ( and ) was also confirmed in soil samples, leaves, grape berries, and fresh grape must. The study confirmed the reduction in the species diversity of the microbiota during the must fermentation process, which resulted in decreases in the concentrations of the monitored biogenic amines in the early stages of the must fermentation process and young wine of the variety Tramín červený.
PubMed: 36230137
DOI: 10.3390/foods11193061 -
Journal of Advanced Pharmaceutical... 2022Pomegranate peels (PGPs) are known to have the potential as antibacterial not only from their nutrient content but also the microflora. The activities might be caused by...
Pomegranate peels (PGPs) are known to have the potential as antibacterial not only from their nutrient content but also the microflora. The activities might be caused by the existence of indigenous yeast that can be utilized to inhibit the growth of pathogenic bacteria. This study aims to identify antibacterial and antioxidant activity of indigenous yeast isolated from PGP. The research was conducted by experimental methods and followed by descriptive analysis. The study was done by the isolation of indigenous yeast from PGPs, which was identified using the rRNA sequence analysis of internal transcribed spacer (ITS) region with the primers of ITS1 (5'-TCCGTAGGTGAACCTGCGG-3') and ITS4 (5'-TCCTCCGCTTATTGATATGC-3') and then compared with Basic Local Alignment Search Tools (BLAST) algorithm toward the GenBank. Antibacterial activities of indigenous yeast were tested with agar plug diffusion and time kill test toward and . The yeast identification obtained two isolates similar to CBS 314 and two isolates of ATCC 6258 which have antibacterial activity against and . PGP D4 have best antimicrobial activities with a strong activity against (±9 mm) and medium activity against (±3.1 mm).
PubMed: 35223442
DOI: 10.4103/japtr.japtr_86_21 -
Microorganisms Sep 2022Kveik are consortia of yeast used for farmhouse ale production in Western Norway. Yeast strains derived from these mixtures are known, for example, for their high...
Kveik are consortia of yeast used for farmhouse ale production in Western Norway. Yeast strains derived from these mixtures are known, for example, for their high fermentation rate, thermotolerance, lack of phenolic off flavor production (POF-) and strong flocculation phenotype. In this study, we used five single cell yeast isolates from different Kveik yeasts, analyzed their fermentation and flavor production, and compared it with a typical yeast used in distilleries using 20 °C and 28 °C as the fermentation temperatures. One of the isolates, Kveik No 3, showed an impairment of maltotriose utilization and thus a reduced ethanol yield. Kveik fermentations for spirit production often harbor bacteria for flavor enrichment. We sought to improve Kveik fermentations with non-conventional yeasts (NCY). To this end we co-fermented Kveik isolates with and using 5:1 ratios (Kveik vs. NCY) at 20 °C. The combinations of Kveik No 1 with and Kveik No 1 with showed substantially increased amounts of specific volatile aroma compounds that were previously identified in the NCYs. Our results indicate that Kveik isolates appear to be suitable for co-fermentations with certain NCY to enhance beer or spirit fermentations, increasing the potential of these yeasts for beverage productions.
PubMed: 36296198
DOI: 10.3390/microorganisms10101922 -
Foods (Basel, Switzerland) Dec 2020Biocontrol is one of the most promising alternatives to synthetic fungicides for food preservation. , and section are the most concerning pathogens for grape...
Biocontrol is one of the most promising alternatives to synthetic fungicides for food preservation. , and section are the most concerning pathogens for grape development. However, frequently, other species, such as in this study, are predominant in spoiled bunches. In this work, 54 native yeasts from vineyards were screened by direct confrontation in potato dextrose agar plates as antagonists against . Isolates of , , and were selected for their antagonist activity in vitro, plus isolates of , and were used as negative controls. However, in vivo, confrontations in wounded grapes showed disagreement with direct confrontation in vitro. , , , and significantly reduced the incidence of on grapes. Nevertheless, , and themselves spoiled the wounded grapes. Inhibitions were associated with different mechanisms such as the production of volatile organic compounds (VOCs), lytic enzymes, biofilm formation, and competition for nutrients. The isolates of L18 (a producer of antifungal VOCs which completely inhibited the incidence of ) and L29 (with pectinase, chitinase and β-glucanase activity and biofilm formation which reduced 70% of the incidence of ) are proposed as suitable biocontrol agents against .
PubMed: 33327475
DOI: 10.3390/foods9121864 -
Sheng Wu Gong Cheng Xue Bao = Chinese... Mar 2024The utilization of industrial microorganisms for the conversion of lignocellulose into high value-added chemicals is an essential pathway towards achieving carbon...
The utilization of industrial microorganisms for the conversion of lignocellulose into high value-added chemicals is an essential pathway towards achieving carbon neutrality and promoting sustainable bioeconomy. However, the pretreated lignocellulase hydrolysate often contains various sugars, salts, phenols/aldehydes and other substances, which requires microorganisms to possess strong tolerance for direct fermentation. This study aims to investigate the tolerance of to substrate, salt, and high temperature shock, in order to validate its potential for utilizing the enzymatic hydrolysate of in seawater for fermentation. The experimental results showed that the adaptively domesticated . exhibited tolerance to glucose at a concentration of 200 g/L and became a hypertonic strain. When seawater was used instead of freshwater without sterilization, the yield of glycerol in fermentation was 109% higher than that in freshwater with sterilization. Moreover, the combined thermal shock at 32 hours of fermentation and addition of 10 NaSO at 48 hours resulted in a yield of glycerol to glucose 0.37 g/g, which was 225% higher than the control group. By fermenting the enzymatic hydrolysate of . pretreated in seawater, the total conversion rate of glucose into glycerol and ethanol reached 0.45 g/g. This study indicates that hypertonic . exhibits remarkable adaptability to substrate, salt, and temperature. It not only can directly utilize complex lignocellulosic hydrolysates, but also exhibits strong tolerance to them. Therefore, it provides a potential candidate strain for the production of bio-based chemicals using lignocellulosic processes.
Topics: Glycerol; Pichia; Fermentation; Glucose; Xylose
PubMed: 38545986
DOI: 10.13345/j.cjb.230432 -
Foods (Basel, Switzerland) Feb 2022The effects of different yeast strains including , , and on the taste and odour profiles of reduced-salt dry sausages were explored. Inoculation of and compensated...
The effects of different yeast strains including , , and on the taste and odour profiles of reduced-salt dry sausages were explored. Inoculation of and compensated for the lack of saltiness and umami tastes of reduced-salt sausages. Furthermore, inoculation of and resulted in an odour profile in the reduced-salt dry sausages that was similar to traditional dry sausages. According to the volatile analysis, the contents of certain alcohols, acids, esters and terpenes were higher in the inoculated sausages. Finally, the sensory evaluation indicated that the inoculation of and contributed positively to the aroma and saltiness of reduced-salt dry sausages. In conclusion, and can be employed as effective starter cultures to compensate for the flavour deficiencies of reduced-salt dry sausages.
PubMed: 35267284
DOI: 10.3390/foods11050650 -
Veterinary World Feb 2023Probiotic supplementation can assist with manipulating the rumen microbial ecosystem. Lactic acid bacteria and yeast from fermented fish (Budu) as the indigenous food...
BACKGROUND AND AIM
Probiotic supplementation can assist with manipulating the rumen microbial ecosystem. Lactic acid bacteria and yeast from fermented fish (Budu) as the indigenous food from West Sumatra, Indonesia, are potential probiotics for livestock. This study aims to select the best candidate lactic acid bacteria and yeast strains from fermented fish as ruminant probiotics and evaluate the effect of their supplementation on the characteristics of rumen fermentation, feed digestion, and total gas production .
MATERIALS AND METHODS
This study used nine treatments, performed in triplicate, in a completely randomized design. The substrate ratio comprised of 70% forage and 30% concentrate. Five lactic acid bacteria and three yeast isolates were used in this study. Treatments were as follows: T0: control (basal diet); T1: T0 + strain 3347; T2: T0 + strain 5296; T3: T0 + JCM 16178; T4: T0 + strain LH991; T5: T0 + strain 6902; T6: T0 + strain B-5P; T7: T0 + strain CBS 5147; and T8: T0 + commercial yeast (). The lactic acid bacteria inoculum contained 1.02 × 10 colony-forming unit (CFU)/mL, while the yeast inoculum contained 1.5 × 10 CFU/mL.
RESULTS
The results showed that four lactic acid bacteria and three yeast produced a higher total gas yield (104-183.33 mL) compared to the control (103 mL). Supplementation with lactic acid bacteria in the rumen fermentation showed dry matter digestibility of 63%-70% and organic matter digestibility (OMD) of 64%-71%. We observed that total volatile fatty acid (VFA) production in all treatments was significantly higher (86-121 mM) compared to the control (81 mM). The concentration of NH production was higher in all treatments (12.33-16.83 mM) than in the control (12.25 mM). Meanwhile, the probiotic supplementation did not cause a significant change in the rumen pH (6.86-7.12). Supplementation with the lactic acid bacteria strain LH991 consistently demonstrated the best results from the parameters of dry and OMD (70.29% and 71.16%, respectively), total VFA (121.67 mM), NH (16.83 mM), and total gas production (149.17 mL). The best results were observed from the yeast candidate strain B-5P, where the results were dry and OMD (67.64% and 69.55% respectively), total VFA (96.67 mM), NH (13.42 mM), and total gas production (183.33 mL).
CONCLUSION
Based on the obtained results, lactic acid bacteria strain LH991 and yeast strain B-5P are attractive candidates to be utilized as probiotics for ruminants based on their potential to improve rumen fermentation . This probiotic supplementation can increase the digestibility of feed ingredients, production of total VFA and NH, and total gas produced.
PubMed: 37041999
DOI: 10.14202/vetworld.2023.395-402 -
Metabolic Engineering Communications Jun 2020Itaconic acid (IA), or 2-methylenesuccinic acid, has a broad spectrum of applications in the biopolymer industry owing to the presence of one vinyl bond and two acid...
Itaconic acid (IA), or 2-methylenesuccinic acid, has a broad spectrum of applications in the biopolymer industry owing to the presence of one vinyl bond and two acid groups in the structure. Its polymerization can follow a similar mechanism as acrylic acid but additional functionality can be incorporated into the extra beta acid group. Currently, the bio-based production of IA in industry relies on the fermentation of the filamentous fungus . However, the difficulties associated with the fermentation undertaken by filamentous fungi together with the pathogenic potential of pose a serious challenge for industrial-scale production. In recent years, there has been increasing interest in developing alternative production hosts for fermentation processes that are more homogenous in the production of organic acids. is a non-conventional yeast with high acid tolerance to organic acids at low pH, which is a highly desirable trait by easing downstream processing. We introduced -aconitic acid decarboxylase gene () from (designated ) into this yeast and established the initial titer of IA at 135 ± 5 mg/L. Subsequent overexpression of a native mitochondrial tricarboxylate transporter (herein designated ) presumably delivered -aconitate efficiently to the cytosol and doubled the IA production. By introducing the newly invented CRISPR-Cas9 system into . , we successfully knocked out both copies of the gene encoding isocitrate dehydrogenase (), aiming to increase the availability of -aconitate. The resulting strain, devoid of and overexpressing and on its genome produced IA at 505 ± 17.7 mg/L in shake flasks, and 1232 ± 64 mg/L in fed-batch fermentation. Because the usage of an acid-tolerant species does not require pH adjustment during fermentation, this work demonstrates the great potential of engineering . as an industrial chassis for the production of organic acid.
PubMed: 32346511
DOI: 10.1016/j.mec.2020.e00124 -
Current Research in Microbial Sciences Dec 2021Endophytic fungi from marine macroalgae are endowed with various pharmacologically active metabolites. This study mined, identified and screened endophytic fungi (EF)...
Endophytic fungi from marine macroalgae are endowed with various pharmacologically active metabolites. This study mined, identified and screened endophytic fungi (EF) isolated from marine algae from the west coast of South India for screening anticancer, antioxidant and antimicrobial secondary metabolite producers. Five EF isolated from sampled marine algae were identified using morphology and ITS based identification as and After culturing 20 days on PDA medium, the ethyl acetate extracts of showed potent antimicrobial activity against with an IC value of 458.7 ± 1.021 µg/mL whereas extracts showed promising antioxidant activity (IC value of 65.78 ± 1.082 µg/mL, 38.74 ± 1.040 µg/mL and 32.01 ± 1.018 µg/mL for DPPH assay, ABTS assay and FRAP assay respectively) and high cytotoxic activity against MG63 cell line (IC = 145.1 ± 1.086 µg/mL, no activity against U87 cells). The phytochemical screening of the extracts unveiled the existence of diverse groups of secondary metabolites. Further, Gas Chromatography Mass Spectroscopy (GC-MS) analysis of the extract revealed the presence of compounds that are known to be antibacterial, antioxidant and cytotoxic. These results indicate that marine derived endophytes could be potent sources for multi-functional bioactive compounds and may find prospective application in pharmaceutical industry.
PubMed: 34841328
DOI: 10.1016/j.crmicr.2021.100037