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1.
Microorganisms ; 12(7)2024 Jun 30.
Artículo en Inglés | MEDLINE | ID: mdl-39065109

RESUMEN

The role of lipopolysaccharide (LPS) in the development of diseases is clear, but the specific mechanisms remain poorly understood. This study aimed to investigate the microbiome aberrations in the guts of mice against the background of LPS, as well as the anti-inflammatory effect of probiotic supplementation with Lactobacillus plantarum from the gut, a mix of commercial probiotic lactic acid bacteria, and Weissella confusa isolated from milk using next-generation sequencing. LPS injections were found to induce inflammatory changes in the intestinal mucosa. These morphological changes were accompanied by a shift in the microbiota. We found no significant changes in the microbiome with probiotic supplementation compared to the LPS group. However, when Lactobacillus plantarum and a mix of commercial probiotic lactic acid bacteria were used, the intestinal mucosa was restored. Weissella confusa did not contribute to the morphological changes of the intestinal wall or the microbiome. Changes in the microbiome were observed with probiotic supplementation of Lactobacillus plantarum and a mix of commercial probiotic lactic acid bacteria compared to the control group. In addition, when Lactobacillus plantarum was used, we observed a decrease in the enrichment of the homocysteine and cysteine interconversion pathways with an increase in the L-histidine degradation pathway.

2.
Antibiotics (Basel) ; 13(7)2024 Jun 28.
Artículo en Inglés | MEDLINE | ID: mdl-39061286

RESUMEN

Growing interest in probiotics has spurred research into their health benefits for hosts. This study aimed to evaluate the probiotic properties, especially antibacterial activities and the safety of two Weissella confusa strains, W1 and W2, isolated from Khao-Mahk by describing their phenotypes and genotypes through phenotypic assays and whole genome sequencing. In vitro experiments demonstrated that both strains exhibited robust survival under gastric and intestinal conditions, such as in the presence of low pH, bile salt, pepsin, and pancreatin, indicating their favorable gut colonization traits. Additionally, both strains showed auto-aggregation and strong adherence to Caco2 cells, with adhesion rates of 86.86 ± 1.94% for W1 and 94.74 ± 2.29% for W2. These high adherence rates may be attributed to the significant exopolysaccharide (EPS) production observed in both strains. Moreover, they exerted remarkable antimicrobial activities against Stenotrophomonas maltophilia, Salmonella enterica serotype Typhi, Vibrio cholerae, and Acinetobacter baumannii, along with an absence of hemolytic activities and antibiotic resistance, underscoring their safety for probiotic application. Genomic analysis corroborated these findings, revealing genes related to probiotic traits, including EPS clusters, stress responses, adaptive immunity, and antimicrobial activity. Importantly, no transferable antibiotic-resistance genes or virulence genes were detected. This comprehensive characterization supports the candidacy of W1 and W2 as probiotics, offering substantial potential for promoting health and combating bacterial infections.

3.
Semin Dial ; 2024 Jul 30.
Artículo en Inglés | MEDLINE | ID: mdl-39078724

RESUMEN

We reported a rare case of peritoneal dialysis-associated peritonitis caused by Weissella confusa. In this case, the symptoms of peritonitis were insidious and atypical, with only turbid peritoneal dialysis effluent and no fever or abdominal pain. The peritoneal dialysis effluent showed slightly elevated leukocytes (predominantly lymphocytes). Weissella confusa was confirmed through repeated peritoneal dialysis effluent cultures. Gastroscopy revealed erosive gastritis with a hookworm infection. The patient recovered after antibiotic and deworming treatments. Our report highlights the unusual and atypical symptoms, characterized by insidious onset, turbid peritoneal dialysis fluid, and an absence of typical signs such as fever or abdominal pain.

4.
J Clin Med ; 13(9)2024 Apr 26.
Artículo en Inglés | MEDLINE | ID: mdl-38731087

RESUMEN

Background: WCFA19 (Weissella confusa WIKIM51), found during the fermentation of kimchi, is known for its inhibitory effects on body weight and body fat. This study looked at the impact of WCFA19 isolated from dandelion kimchi on weight loss in overweight and obese adults that are otherwise healthy. Methods: This study was conducted as a multicenter, double-blind, randomized, placebo-controlled study with 104 overweight and obese subjects. Subjects were randomized evenly into the test group (WCFA19, 500 mg, n = 40) or control group (n = 34) for 12 weeks from 14 June 2021 to 24 December 2021. Effects were based on DEXA to measure changes in body fat mass and percentage. Results: Among the 74 subjects analyzed, WCFA19 oral supplementation for 12 weeks resulted in a significant decrease in body fat mass of 633.38 ± 1396.17 g (p = 0.0066) in overweight and obese individuals in the experimental group. The control group showed an increase of 59.10 ± 1120.57 g (p = 0.7604), indicating a statistically significant difference between the two groups. There was also a statistically significant difference (p = 0.0448) in the change in body fat percentage, with a decrease of 0.41 ± 1.22% (p = 0.0424) in the experimental group and an increase of 0.17 ± 1.21% (p = 0.4078) in the control group. No significant adverse events were reported. Conclusions: Oral supplementation of 500 mg of WCFA19 for 12 weeks is associated with a decrease in body weight, particularly in body fat mass and percentage.

5.
Int J Biol Macromol ; 264(Pt 1): 130507, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38428765

RESUMEN

Exopolysaccharide (EPS) producing Lactic Acid Bacteria (LAB) species can be presented in distinct environments. In this study, Turkish fermented sausage (sucuk) was tested for the presence of EPS producer LAB strains and slimy-mucoid colonies were selected for further tests. Among the isolates, Weissella confusa strain S6 was identified and tested for the physicochemical characterisation of its EPS. This strain was found to produce 0.74 g L-1 of EPS in modified BHI medium conditions. Structural characterisation of EPS S6 by 1H and 13C NMR demonstrated that EPS S6 was a highly branched dextran type glucan formed by mainly (1 â†’ 2)-linked α-d-glucose units together with low levels of (1 â†’ 3)-linked α-d-glucose units as branching points. This structure was further confirmed by methylation analysis detected by GC-MS. An average molecular weight of 8 × 106 Da was detected for dextran S6. The FTIR analysis supported the dextran structure and revealed the presence of distinct functional groups within dextran S6 structure. A strong thermal profile was observed for dextran S6 detected by DSC and TGA analysis and dextran S6 revealed a degradation temperature of 289 °C. In terms of physical status, dextran S6 showed amorphous nature detected by XRD analysis. SEM analysis of dextran S6 demonstrated its rough, compact and porous morphology whereas AFM analysis of dextran S6 detected in its water solution showed the irregularity with no clear cross-link within the dextran chains. These technological features of dextran S6 suggests its potential to be used for in situ or ex situ application during meat fermentations.


Asunto(s)
Lactobacillales , Weissella , Dextranos/química , Weissella/metabolismo , Glucosa/metabolismo , Espectroscopía de Resonancia Magnética
6.
Antioxidants (Basel) ; 13(2)2024 Jan 28.
Artículo en Inglés | MEDLINE | ID: mdl-38397763

RESUMEN

Lactic acid bacteria (LAB) produce important metabolites during fermentation processes, such as exopolysaccharides (EPS), which represent powerful natural antioxidants. On the other hand, H. sabdariffa L. anthocyanin extracts protect LAB and support their development. This study uncovers for the first time, the antioxidant profile of Weissella confusa PP29 probiotic media and focuses on elevating its impressive antioxidant attributes by synergistically integrating H. sabdariffa L. anthocyanin extract. The multifaceted potential of this innovative approach is explored and the results are remarkable, allowing us to understand the protective capacity of the fermented product on the intestinal mucosa. The total phenolic content was much lower at the end of the fermentation process compared to the initial amount, confirming their LAB processing. The DPPH radical scavenging and FRAP of the fermented products were higher compared to ascorbic acid and antioxidant extracts, while superoxide anion radical scavenging and lipid peroxidation inhibitory activity were comparable to that of ascorbic acid. The antioxidant properties of the fermented products were correlated with the initial inoculum and anthocyanin concentrations. All these properties were preserved for 6 months, demonstrating the promising efficacy of this enriched medium, underlining its potential as a complex functional food with enhanced health benefits.

7.
Artículo en Inglés | WPRIM (Pacífico Occidental) | ID: wpr-1030524

RESUMEN

Aims@#The aim of this study was to identify an isolate B, an exopolysaccharide (EPS)-producing lactic acid bacteria and determine the fermentation time effect on EPS production. @*Methodology and results@#Isolate B, an EPS producer, was isolated from peanut milk containing commercial sugar, which was fermented spontaneously for 24 h. Isolate B was identified biochemically using API 50 CH and molecularly based on 16S rDNA. The effect of fermentation time on EPS production by isolate B with variations of the fermentation time were 12, 24, 36, 48 and 60 h. Isolate B was able to produce EPS qualitatively by producing mucoid colonies on solid media containing sucrose. The identification revealed that this isolate was Weissella confusa both biochemically using API 50 CH and molecularly based on 16S rDNA sequence homology-based method. The fermentation time significantly affected EPS production (P<0.05). Isolate B (W. confusa) produced the highest EPS (10.41 g/L) at 36 h with a cell viability of 6.5 × 108 CFU/mL. Furthermore, the FTIR results of EPS showed absorption bands characteristic of carbohydrates, including O-H, C-H, C=O, C-O-C and α-1,6 glycosidic groups. The EPS in this study was most likely a dextran type.@*Conclusion, significance and impact of study@#The yield of EPS production was influenced by fermentation time. Results suggest that W. confusa isolated from peanut milk had a good ability for EPS production. Therefore, it can be considered further to apply this strain for the production of EPS. However, further research is required.

8.
BioTech (Basel) ; 12(4)2023 Nov 09.
Artículo en Inglés | MEDLINE | ID: mdl-37987480

RESUMEN

This mini review deals with some controversial non-starter lactic acid bacteria (NSLAB) species known to be both human and animal pathogens but also health-promoting and probiotic. The focus is on Lactococcus garvieae, two Streptococcus species (S. uberis and S. parauberis), four Weissella species (W. hellenica, W. confusa, W. paramesenteroides, and W. cibaria), and Mammalicoccus sciuri, which worldwide, are often found within the microbiotas of different kinds of cheese, mainly traditional artisanal cheeses made from raw milk and/or relying on environmental bacteria for their ripening. Based on literature data, the virulence and health-promoting effects of these bacteria are examined, and some of the mechanisms of these actions are reviewed. Additionally, their possible roles in cheese ripening are also discussed. The analysis of the literature data available so far showed that, in general, the pathogenic and the beneficial strains, despite belonging to the same species, show somewhat different genetic constitutions. Yet, when the safety of a given strain is assessed, genomic analysis on its own is not enough, and a polyphasic approach including additional physiological and functional tests is needed.

9.
Food Chem X ; 19: 100823, 2023 Oct 30.
Artículo en Inglés | MEDLINE | ID: mdl-37780240

RESUMEN

Non-dairy yogurt is increasingly thought to be healthy food. However, no suitable starters limit its development. This study aimed to develop a novel and functional quinoa yogurt with a modified commercial starter. Compared with the other lactic acid bacteria (LAB), Weissella confusa showed a better fermentation performance of quinoa utilization. The synergistic effect of W. confusa and the commercial starter promoted the growth of LAB. It increased the fermentation rate of quinoa yogurt, further improving its texture, rheological properties, and storage stability. The modified starter significantly increased the nutritional qualities of the quinoa yogurt, including polyphenol content, antioxidant activity, digestive enzyme inhibition, and reduced postprandial blood glucose ability. Additionally, the modified starter enhanced the digestibility and bioaccessibility of polyphenols, protein, and fat in fermented quinoa yogurt. Overall, the commercial starter with W. confusa showed great potential for possible application in quinoa yogurt development.

10.
Artículo en Inglés | MEDLINE | ID: mdl-37632675

RESUMEN

The application of probiotics, in aquaculture, is becoming increasingly widespread and have had positive application effects. However, reports of loach-derived probiotics are quite limited. In this study, two representative strains of lactic acid bacteria with excellent traits, namely, Weissella confusa N17 and Lactobacillus saniviri N19, were screened from the intestine of healthy loaches. W. confusa N17 and L. saniviri N19 could inhibit different common various pathogenic bacteria, especially Aeromonas spp., and were sensitive to the most common antibiotics. The survival rate of the two strains exceeded 50% after 4 h of incubation in 10% loach bile. Moreover, the two strains showed significant tolerance to trypsin. Their autoaggregation capacity and hydrophobicity were greater than 30%. In addition, the aggregation ability of both strains was higher than 30% for both A. veronii TH0426 and A. hydrophila TPS. The two strains had a high biofilm-forming ability and strong adhesion to epithelioma papulosum cyprini (EPC) cells. Scanning electron microscopy results showed that the culture supernatants of the two strains had a significantly destructive effect on A. veronii TH0426 and A. hydrophila TPS. Overall, the traits of W. confusa N17 were better than those of L. saniviri N19. Genome sequencing and analysis demonstrated a lack of virulence factor-related or drug resistance-related genes in genome N17. The diet supplemented with the W. confusa N17 strain significantly improved the resistance of loaches to A. veronii infection, and the protection rate reached 57.1%. Therefore, W. confusa N17 exhibits promising for further applications in loach aquaculture.

11.
BMC Res Notes ; 16(1): 178, 2023 Aug 22.
Artículo en Inglés | MEDLINE | ID: mdl-37608379

RESUMEN

OBJECTIVE: This study was performed to investigate the potential effects of Weissella confusa F213 (WCF213) on chemically-induced colitis rats. Twelve male Wistar rats were divided into three groups: T1 (saline sterile), T2 (2.5% dextran sulfate sodium (DSS)- for 7 days), and T3 (WCF213 for 14 days, continued with 2.5% DSS for 7 days). The disease activity index (DAI) was monitored. After sacrificing the rats, the colon was collected for length measurement, local TNF-α level, HE staining for histology, and ZO-1 expression by using immunohistochemistry. RESULTS: WCF213 administration prevented weight loss and haematochezia, maintained average colon length and alleviated the clinical symptom of colitis, such as diarrhoea, albeit statistically non-significant (p < 0.05) compared with the T2 group. The histopathology of WCF213-treated colitis rats showed better architecture and less inflammatory cell infiltration into colon tissue. WCF213 significantly maintained the expression of ZO-1 in the mucosa (p < 0.001) and markedly reduced mucosal TNF-α concentration (p < 0.001) compared with the DSS group. Hence, these findings suggested that WCF213 attenuated clinical symptoms and inflammation and maintained mucosal integrity in DSS-induced colitis in vivo.


Asunto(s)
Colitis , Masculino , Ratas , Animales , Factor de Necrosis Tumoral alfa , Ratas Wistar , Colitis/inducido químicamente , Colitis/tratamiento farmacológico , Inflamación/tratamiento farmacológico , Mucosa Intestinal
12.
Infect Drug Resist ; 16: 4571-4577, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37465184

RESUMEN

Introduction: W. confusa has been known to cause various human infections. It is naturally resistant to vancomycin and is difficult to identify using traditional methods, which may lead to misidentification and delay treatment. Case Presentation: We present a case of a 42-year-old male patient with gastrointestinal bleeding and coronary heart disease who developed sepsis caused by Weissella confusa. The patient's blood cultures showed the presence of gram-positive coccobacilli, later identified as W. confusa through matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Antimicrobial susceptibility testing revealed that W. confusa had low minimum inhibitory concentrations (MICs) for some drugs (eg, ampicillin) and higher MICs for others (eg, cefotaxime). Empirical treatment with vancomycin was initially started, but after obtaining the identification and susceptibility results, the treatment was switched to meropenem combined with daptomycin, resulting in a successful outcome. Conclusion: Weissella confusa bacteremia is relatively rare, and accurate pathogenic diagnosis is essential for effective clinical treatment.

13.
Int J Mol Sci ; 24(13)2023 Jul 02.
Artículo en Inglés | MEDLINE | ID: mdl-37446188

RESUMEN

Although Weissella cibaria and W. confusa are essential food-fermenting bacteria, they are also opportunistic pathogens. Despite these species being commercially crucial, their taxonomy is still based on inaccurate identification methods. In this study, we present a novel approach for identifying two important Weissella species, W. cibaria and W. confusa, by combining matrix-assisted laser desorption/ionization and time-of-flight mass spectrometer (MALDI-TOF MS) data using machine-learning techniques. After on- and off-plate protein extraction, we observed that the BioTyper database misidentified or could not differentiate Weissella species. Although Weissella species exhibited very similar protein profiles, these species can be differentiated on the basis of the results of a statistical analysis. To classify W. cibaria, W. confusa, and non-target Weissella species, machine learning was used for 167 spectra, which led to the listing of potential species-specific mass-to-charge (m/z) loci. Machine-learning techniques including artificial neural networks, principal component analysis combined with the K-nearest neighbor, support vector machine (SVM), and random forest were used. The model that applied the Radial Basis Function kernel algorithm in SVM achieved classification accuracy of 1.0 for training and test sets. The combination of MALDI-TOF MS and machine learning can efficiently classify closely-related species, enabling accurate microbial identification.


Asunto(s)
Weissella , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción , Aprendizaje Automático
14.
Food Sci Biotechnol ; 32(4): 553-564, 2023 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-36911327

RESUMEN

Weissella bacteria are gram-positive, anaerobic, fermentative, and have probiotic potential. This study aimed to compare the genomes of W. cibaria YRK005 and W. confusa CCK931 isolated from young radish and kimchi, respectively. The genomic size of W. cibaria YRK005 and W. confusa CCK931 with GC content is 2.36 Mb (45%) and 2.28 Mb (44.67%), respectively. The genome study identified 92 and 83 CAZymes genes, respectively, for W. cibaria YRK005 and W. confusa CCK931, that are responsible for 26 and 27 glycoside hydrolases (GH) and 21 and 27 glycosyl transferases. Both species have one gene for carbohydrate esterases and three genes for carbohydrate-binding modules. The primary CAZymes found in both species that are involved in oligosaccharide utilization are GH1, GH2, GH30, GH13_30, GH13_31, GH42, GH43, and GH65. The study also details the production pathways for glycogen and folate. Both strains include a unique repertoire of genes, including hypothetical proteins, showing adaptability to diverse ecological niches and evolution over time. Supplementary Information: The online version contains supplementary material available at 10.1007/s10068-022-01232-7.

15.
Heliyon ; 9(3): e13837, 2023 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-36915561

RESUMEN

The aim of the study was to evaluate the acceptability of composite breads based on local cereal (millet and sorghum) formulations. Bread preparations based on 50% wheat flour and 50% local cereal flour were made in the presence of exopolysaccharide (Eps) production stimulated by a strain of Weissella confusa A16 in the fermented dough. Seven formulations were done in two baking sets and were submitted to sensory evaluations which consisted of tests on sensory profile, hedonic analysis and ranking. Results showed that the presence of Eps improved the acceptability of breads made with local cereal flours. The white color of the crumb of breads made with 100% wheat flour was the most appreciated by consumers. The less local flour is used in the bread preparation, the better the bread is appreciated. Nevertheless, formulations containing whole grains were the least appreciated, partly because of the hardness of the breads. Interestingly, more than 50% of consumers found the taste pleasant for breads made with 50% millet flour.

16.
Saudi J Biol Sci ; 30(4): 103595, 2023 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-36873575

RESUMEN

Different strategies have been approved for controlling extended-spectrum ßeta lactamase (ESBL) producing uropathogenic bacteria. The antibacterial activity of Lactic acid bacteria (LAB) is an effective strategy due to its probiotic characteristics and beneficial effects on human health. The antibiotic susceptibility test, disk diffusion method, and double disc synergy test indicated that five enteric uropathogenic isolates were ESBL producers during the present study. They recorded diameters of inhibition zones as ≤ 18, ≤ 8, ≤ 19, and ≤ 8 mm against cefotaxime (CTX), ceftazidime (CAZ), aztreonam (ATM), and ceftriaxone (CRO). Genotypically, blaTEM genes are the most common, with (100 %) occurrence in all the five enteric tested uropathogens, followed by blaSHV and blaCTX genes (60 %). In addition, out of 10 LAB isolates from dairy products, the CFS of isolate no. K3 had high antibacterial activity against the tested ESBLs, especially no. U60, with a MIC of 600 µl. Additionally, the MIC and sub-MIC of K3 CFS inhibited the production of antibiotic-resistant bla TEM genes of U60. Analyzing the 16S rRNA sequence confirmed that the most potent ESBL-producing bacteria (U60) and LAB (K3) isolates were identified as Escherichia coli U60.1 and Weissella confuse K3 with accession numbers MW173246 and MW173299.1, respectively, in GenBank.

17.
Foods ; 11(22)2022 Nov 10.
Artículo en Inglés | MEDLINE | ID: mdl-36429171

RESUMEN

Fermentation with Weissella confusa A16 could improve the flavor of various plant-based sources. However, less is known about the influence of fermentation conditions on the profile of volatile compounds, dextran synthesis and acidity. The present work investigates the synthesis of potential flavor-active volatile compounds, dextran, acetic acid, and lactic acid, as well as the changes in viscosity, pH, and total titratable acidity, during fermentation of faba bean protein concentrate with W. confusa A16. A Response Surface Methodology was applied to study the effect of time, temperature, dough yield, and inoculum ratio on the aforementioned responses. Twenty-nine fermentations were carried out using a Central Composite Face design. A total of 39 volatile organic compounds were identified: 2 organic acids, 7 alcohols, 8 aldehydes, 2 alkanes, 12 esters, 3 ketones, 2 aromatic compounds, and 3 terpenes. Long fermentation time and high temperature caused the formation of ethanol and ethyl acetate and the reduction of hexanal, among other compounds linked to the beany flavor. Levels of dextran, acetic acid, and lactic acid increased with increasing temperature, time, and dough yield. Optimal points set for increased dextran and reduced acidity were found at low temperatures and high dough yield. Such conditions would result in hexanal, ethyl acetate and ethanol having a relative peak area of 35.9%, 7.4%, and 4.9%, respectively.

18.
Food Sci Biotechnol ; 31(13): 1703-1715, 2022 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-36312995

RESUMEN

In this work, the in vivo functionalities of milk fermented with Weissella confusa VP30 (VP30-EPS) and purified exopolysaccharide (pEPS) from the milk fermented with Weissella confusa VP30 were evaluated for their effect on constipation using an experimental constipated rat model. Rats were randomly divided into four groups: (i) control group (PBS administered normal group), (ii) loperamide treated group (constipation group), (iii) constipation with loperamide plus VP30-EPS (1 g/kg), and (iv) constipation with loperamide plus pEPS (0.6 g/kg) groups. Loperamide treatment induced animal constipation and significantly reduced the frequency of defecation, intestinal transit ratio, and water content of feces. However, all four fecal parameters were improved in both the loperamide plus VP30-EPS and pEPS administered groups as compared to the loperamide group. These results suggest that the addition of VP30-EPS potentially improves the functional laxative effects of commercial products. This study suggests the possibility that VP30-EPS can be applied to fermented and/or functional foods to relieve constipation.

19.
Int J Biol Macromol ; 204: 677-684, 2022 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-35181327

RESUMEN

An EPS produced by Weissella confusa H2 was purified through Sephadex G-100, and the preliminary structure characteristics and biological activities of H2 EPS were analyzed. Molecular mass of purified H2 EPS was 2.705 × 106 Da as measured with gel permeation chromatography (GPC). Composition of monosaccharides, nuclear magnetic resonance (NMR) spectroscopy spectroscopy and fourier transform infrared (FT-IR) showed that the EPS was a linear homopolysaccharide, mainly constituted of glucose and it is suggested that the EPS was dextran with α-(1 â†’ 6) glycosidic bonds and a few α-(1 â†’ 3) branches. Atomic force micrograph (AFM) and scanning electron microscopy (SEM) analysis of dextran further revealed sheets branched microstructure anchored with many irregular protuberances in aqueous solution. The XRD pattern reflected non-crystalline amorphous nature. In addition, the solubility, water-holding capacity, thermal property, rheological property and heavy metal chelating activity of the purified H2 dextran were determined. The dissolution percentage and water holding capacity of the dextran were 98.78 ± 1.37% and 426.03 ± 7.26%, respectively. The dextran exhibited good hydrophilicity, thermal stability and heavy metal chelating activity. Rheological studies exhibited rotational speed, pH, temperature, metal ions solutions dependent semiviscous nature. These results support its use as an additive in the food and environmental protection fields.


Asunto(s)
Dextranos , Weissella , Dextranos/química , Peso Molecular , Polisacáridos Bacterianos/química , Espectroscopía Infrarroja por Transformada de Fourier , Weissella/química
20.
Front Microbiol ; 12: 757542, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34925267

RESUMEN

Citrulline is one of the major precursors of ethyl carbamate in soy sauce, and the accumulation of citrulline is attributed to the metabolism of arginine by bacteria with the arginine deiminase (ADI) pathway. However, key strains and factors affecting citrulline accumulation are not yet clear. In this study, two key strains of Pediococcus acidilactici and Weissella confusa were isolated from soy sauce moromi, and the regularity of citrulline formation was studied. Results showed that the conversion rates from arginine to citrulline (A/C rate) and the citrulline accumulation ability of W. confusa and P. acidilactici significantly increased in the presence of different concentrations of NaCl, indicating that salt stress was the main factor for citrulline accumulation. The inconsistent expression of arc genes by salt stress was the reason for citrulline accumulation for P. acidilactici, but for W. confusa, it may be due to the influence of arginine/citrulline on the transportation system: the intracellular citrulline could neither transport to extracellular space nor convert into ornithine. Environmental factors greatly influenced citrulline accumulation of the two key bacteria; A/C rate and citrulline formation in both strains decreased at low temperature (15°C) under high salt stress, but opposite effects were observed for the two key strains under anaerobic light condition. Moreover, quercetin and gallic acid significantly decreased the A/C rate and citrulline accumulation ability of the two key strains. The optimal quercetin and gallic acid as suggested by simulation experiment were 100 and 10 mg/l, respectively, and the lowest A/C rate of 28.4% and citrulline level of 1326.7 mg/l were achieved in the simulation system. This study explored the main factors for citrulline formation by the two key strains and proposed a targeted way to control citrulline in soy sauce.

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