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The effects of ultrasound (US) on probiotics, as health-promoting microbes, have attracted the attention of researchers in fermentation and healthy food production. This paper aims to review recent advances in the application of the US for enhancing probiotic cells' activity, elaborate on the mechanisms involved, explain how probiotic-related industries can benefit from this emerging food processing technology, and discuss the perspective of this innovative approach. Data showed that US could enhance fermentation, which is increasingly used to enrich agri-food products with probiotics. Among the probiotics, recent studies focused on Lactiplantibacillus plantarum, Lactobacillus brevis, Lactococcus lactis, Lactobacillus casei, Leuconostoc mesenteroides, Bifidobacteria. These bacteria proliferated in the log phase when treated with US at relatively low-intensities. Also, this non-thermal technology increased extracellular enzymes, mainly β-galactosidase, and effectively extracted antioxidants and bioactive compounds such as phenolics, flavonoids, and anthocyanins. Accordingly, better functional and physicochemical properties of prebiotic-based foods (e.g., fermented dairy products) can be expected after ultrasonication at appropriate conditions. Besides, the US improved fermentation efficiency by reducing the production time, making probiotics more viable with lower lactose content, more oligosaccharide, and reduced unpleasant taste. Also, US can enhance the rheological characteristics of probiotic-based food by altering the acidity. Optimizing US settings is suggested to preserve probiotics viability to achieve high-quality food production and contribute to food nutrition improvement and sustainable food manufacturing. HIGHLIGHTS: Ultrasound affects probiotics during fermentation to produce healthy foods Ultrasound could enhance the activity of probiotic cells through various mechanisms Lactobacillus plantarum, L. brevis, and Leuconostoc mesenteroides are most studied probiotics Sonication could increase extracellular enzyme and antioxidant activity of fermented foods [ABSTRACT FROM AUTHOR]

Background: Yeast Saccharomyces cerevisiae is widely recognised as a versatile chassis for constructing microbial cell factories. However, producing chemicals from toxic, highly concentrated, or cell-impermeable substrates, or chemicals dependent on enzymatic reactions incompatible with the yeast's intracellular environment, remains challenging. One such chemical is 2-O-(α-D-glucopyranosyl)-sn-glycerol (glucosyl glycerol, αGG), a natural osmolyte used in the cosmetics and healthcare industries. This compound can be synthesised in a one-enzyme reaction from sucrose and glycerol by Leuconostoc mesenteroides sucrose phosphorylase (SucP), an enzyme which, in a low-water, glycerol-rich, phosphate-free environment, transfers the glucosyl moiety from sucrose to glycerol. Results: In this study, we engineered a yeast microbial cell factory for αGG production. For this purpose, we first focused on the abundant yeast GPI-anchored cell wall protein Ccw12 and used our insights to develop a miniature Ccw12-tag, which adds only 1.1 kDa to the enzyme of interest while enabling its covalent attachment to the cell wall. Next, we Ccw12-tagged SucP and expressed it in an invertase-negative strain of yeast S. cerevisiae from the PHO5 promoter, i.e., promoter strongly induced under phosphate-free conditions. Such SucP isoform, covalently C-terminally anchored to the outer cell surface, produced extracellularly 37.3 g l− 1 (146 mM) of αGG in five days, while the underlying chassis metabolised reaction by-products, thereby simplifying downstream processing. Conclusions: The here-described S. cerevisiae strain, displaying C-terminally anchored sucrose phosphorylase on its cell surface, is the first eukaryotic microbial cell factory capable of a one-step αGG production from the readily available substrates sucrose and glycerol. [ABSTRACT FROM AUTHOR]

This study aimed to assess the feasibility of employing indigenous cyanide-degrading bacterial strains for the treatment of cassava mill effluent (CME) in Nigeria, a hazardous waste material posing significant public health risks. The physicochemical properties and heavy metal concentrations in CME were determined through standard methodologies. Cyanide-degrading bacteria were isolated, characterized, and identified using molecular techniques. These strains were immobilized within a porous network of cross-linked biochar, confirmed through SEM imaging, and evaluated alongside free cells for CME bioremediation. Multiple variables were examined to assess the effluent's pollution load, including pH, electrical conductivity (EC), chemical oxygen demand (COD), biochemical oxygen demand (BOD5), total dissolved solids (TDS), nitrate (NO3), phosphate (PO4), and cyanide levels, falling within respective ranges of (4.00-4.02), (2394-2618 S/cm), (985-1219 mg/L), (1556-1667 mg/L), (3459-3705 mg/L), (2709-2812 mg/L), (251-311 mg/L), (87.25-118 mg/L), and (25.00-28 mg/L). Copper was the most prevalent heavy metal in the effluent, while chromium was detected at the lowest levels, with mean values of 10.00-12.39 mg/L and 0.00-0.27 mg/L, respectively. The study revealed severe contamination of the effluent, above the Federal Environmental Protection Agency (FEPA) threshold limit. The 16S rDNA of the cyanide degrading bacteria were deposited at the NCBI database and the following GenBank accession numbers were assigned (MK71248O, MK71281, MK712482, and MK712483) for Pseudomonas putida, Bacillus subtilis, Alcaligenes faecalis and Leuconostoc mesenteroides respectively. Results of the bioremediation approach demonstrated a substantial reduction in physicochemical parameters and heavy metal contents, indicating a promising biological treatment strategy to mitigate CME's adverse effects on public health. In conclusion, despite elevated physicochemical parameters and heavy metal concentrations in CME, this study offers a promising avenue for employing biological treatments to mitigate environmental and public health impacts. Further research and application of this technique hold substantial potential for cassava mill effluent management in Nigeria and other regions facing similar challenges. [ABSTRACT FROM AUTHOR]

Comparative metatranscriptomics of the bacterial and yeast communities of two milk kefir beverages (MKAA1 and MKAA2) was carried out. They were obtained by fermentation with two different frozen stocks of the kefir grain CIDCA AGK1, differing in rheological features and production of organic acids. We hypothesised that the differences in their physicochemical and rheological properties might be due to the microbial activity in each product. The dominance of lactic acid bacteria, yeast, and a marginal amount of acetic acid bacteria characterised the microbiome. The bacterial families Lactobacillaceae and Streptococcaceae accounted for almost all of the bacterial gene transcripts, with Lactobacillus helveticus, L. kefiranofaciens, L. gallinarum, and Lactococcus lactis being most frequent in the microbiome of the MKAA1 beverage and L. kefiranofaciens, Lc. Lactis, and Leuconostoc mesenteroides being the most prevalent in MKAA2. Dipodascaceae and Saccharomycetaceae were the leading yeast families, represented by Yarrowia lipolytica, Saccharomyces unisporus, and Kluyveromyces marxianus. MKAA1 and MKAA2 shared >75% KEGG Ortologs (KOs) in their bacteria and yeast libraries. The considerable decreases in total expressed genes (KEGG Ortologs) assigned to Lactobacillus helveticus and L. gallinarum might be related to the variations in the rheological features of the beverages, probably by compromising the interrelations with L. kefiranofaciens, which might explain the variations in the rheological features of the beverages. [ABSTRACT FROM AUTHOR]

A species-specific multiplex-PCR method and phenotypic tests were combined to evaluate biochemical and genotypic differences between 24 representative Leuconostoc mesenteroides diverse isolates previously found to dominate in spoiled, vacuum-packed Anthotyros whey cheeses stored at 4 °C for 40 days and identified by 16S rRNA gene sequencing. Based on their phenotypic (API 50 CHL) profiles, the 24 isolates comprised 6 multi-strain and 7 single-strain biotypes. Only two single-strain biotypes (L4A and L4B) produced slime (dextran) from sucrose, and only four biotypes (L2A–L2C, L3; 7 isolates) fermented L-arabinose; the remaining 15 isolates (biotypes L1A–L1F) were dextran-negative, oligofermenting Ln. mesenteroides variants, able to ferment D-xylose and grow at 37 °C. Based on their multiplex-PCR (rpoB, araA, dsr, and sorA) gene profiles in comparison with those of the type strains of the four Ln. mesenteroides subsp. cremoris (rpoB), dextranicum (rpoB/dsr), mesenteroides (rpoB/araA/dsr/sorA), and jonggajibkimchii (rpoB/araA/dsr), no isolate was assigned to the first two subspecies and only four isolates (L2A and L2C) to the subsp. mesenteroides. Ten isolates shared the subsp. jonggajibkimchii profile, while the other ten ones have a fifth atypical profile (rpoB/dsr/sorA), seemingly being closer to the subsp. dextranicum. Particularly the atypical biotype L1B representatives of the most prevalent psychrotrophic Ln. mesenteroides subsp. jonggajibkimchii (rpoB/araA/dsr) genotype at Anthotyros whey cheese spoilage deserve further biochemical and molecular characterization studies. [ABSTRACT FROM AUTHOR]

Summary: In this study, six groups of carrots were designed and fermented using Weissella paramensenteroides MbWp142 (WP), Levilactobacillus brevis GDMCC 1.773 (LS), Leuconostoc mesenteroides GDMCC 1.774 (SE), mixed fermentation of three lactic acid bacteria (WP + LS + SE), pasteurisation group (BG) and natural fermentation group (CK). GC–MS results indicated that inoculation of WP + LS + SE increased the types and contents of flavour substances such as alcohols, esters and hydrocarbons. Compared with other experimental groups, the peak nitrite value in the LS group was lower due to the production of organic acids by lactic acid bacteria. Sensory evaluation revealed that the quality and flavour of carrot fermented by LS were superior to those fermented by SE, WP and WP + LS + SE. Therefore, Levilactobacillus brevis used as a starter for fermenting carrot can enhance product quality and reduce nitrite accumulation during fermentation. [ABSTRACT FROM AUTHOR]

In this work, we present a comprehensive investigation of the entrapment of laccase, a biotechnologically relevant enzyme, into levan-based nanoparticles (LNPs). The entrapment of laccase was achieved concomitantly with the synthesis of LNP, catalyzed by a truncated version of a levansucrase from Leuconostoc mesenteroides. The study aimed to obtain a biocompatible nanomaterial, able to entrap functional laccase, and characterize its physicochemical, kinetic and thermal stability properties. The experimental findings demonstrated that a colloidal stable solution of spherically shaped LNP, with an average diameter of 68 nm, was obtained. An uniform particle size distribution was observed, according to the polydispersity index determined by DLS. When the LNPs synthesis was performed in the presence of laccase, biocatalytically active nanoparticles with a 1.25-fold larger diameter (85 nm) were obtained, and a maximum load of 243 μg laccase per g of nanoparticle was achieved. The catalytic efficiency was 972 and 103 (μM·min)-1, respectively, for free and entrapped laccase. A decrease in kcat values (from 7050 min-1 to 1823 min-1) and an increase in apparent Km (from 7.25 μM to 17.73 μM) was observed for entrapped laccase, compared to the free enzyme. The entrapped laccase exhibited improved thermal stability, retaining 40% activity after 1 h-incubation at 70°C, compared to complete inactivation of free laccase under the same conditions, thereby highlighting the potential of LNPs in preserving enzyme activity under elevated temperatures. The outcomes of this investigation significantly contribute to the field of nanobiotechnology by expanding the applications of laccase and presenting an innovative strategy for enhancing enzyme stability through the utilization of fructan-based nanoparticle entrapments. [ABSTRACT FROM AUTHOR]

Dextransucrases play a crucial role in the production of dextran from economical sucrose; therefore, there is a pressing demand to explore novel dextransucrases with better performance. This study characterized a dextransucrase enzyme, LmDexA, which was identified from the Leuconostoc mesenteroides NN710. This bacterium was isolated from the soil of growing dragon fruit in Guangxi province, China. We successfully constructed six different N-terminal truncated variants through sequential analysis. Additionally, a truncated variant, ΔN190LmDexA, was constructed by removing the 190 amino acids fragment from the N-terminal. This truncated variant was then successfully expressed heterologously in Escherichia coli and purified. The purified ΔN190LmDexA demonstrated optimal hydrolysis activity at a pH of 5.6 and a temperature of 30 °C. Its maximum specific activity was measured to be 126.13 U/mg, with a Km of 13.7 mM. Results demonstrated a significant improvement in the heterologous expression level and total enzyme activity of ΔN190LmDexA. ΔN190LmDexA exhibited both hydrolytic and transsaccharolytic enzymatic activities. When sucrose was used as the substrate, it primarily produced high-molecular-weight dextran (>400 kDa). However, upon the addition of maltose as a receptor, it resulted in the production of a significant amount of oligosaccharides. Our results can provide valuable information for enhancing the characteristics of recombinant dextransucrase and potentially converting sucrose into high-value-added dextran and oligosaccharides. [ABSTRACT FROM AUTHOR]

Globally colorectal cancer ranks as the third most widespread disease and the third leading cause of cancer-associated mortality. Immunotherapy treatments like PD-L1 blockade have been used to inhibit the PD-L1 legend, which boosts the activity of cytotoxic T lymphocytes. Recently, studies suggest that some probiotics could potentially enhance the effectiveness of immunotherapy treatments for cancer patients. We found that in Caco-2 and HT-29 cells, the live Leuconostoc mesenteroides treatment resulted an increase in the PD-L1 expression and this treatment stimulated interferon-gamma (IFN-γ) production in Jurkat T-cells. Due to the well-established ability of IFN-γ to enhance PD-L1 expression, the combination of IFN-γ and L. mesenteroides was used in colon cancer cell lines and a resulting remarkable increase of over tenfold in PD-L1 expression was obtained. Interestingly, when L. mesenteroides and IFN-γ are present, the blockage of PD-L1 using PD-L1 antibodies not only improved the viability of Jurkat T-cells but also significantly boosted the levels of IFN-γ and IL-2, the T-cells activation marker cytokines. In addition to upregulating PD-L1, L. mesenteroides also activated Toll-like receptors (TLRs) and NOD-like receptors (NODs) pathways, specifically through TLR2 and NOD2, while also exerting a suppressive effect on autophagy in colon cancer cell lines. In conclusion, our findings demonstrate a significant upregulation of PD-L1 expression in colon cancer cells upon co-culturing with L. mesenteroides. Moreover, the presence of PD-L1 antibodies during co-culturing activates Jurkat T cells. The observed enhancement in PD-L1 expression may be attributed to the inhibition of the Autophagy pathway or activation of the hippo pathway. The administration of Live Lactobacillus mesenteroides on colon cancer cells leads to the elevation of PD-L1, with a further increase observed in the presence of IFN-γ. Co-cultivation of Live L. mesenteroides with colon cancer cells in conjunction with anti-PD-L1 blockade antibody results in the enhanced viability of T cells. Key Points: Co-culturing L. mesenteroides increases PD-L1 gene and protein transaction in colon cancer. L. mesenteroides existing enhances T cells viability and activity. GPCR41/42 is a possible link between L. mesenteroides, YAP-1 and PD-L1. [ABSTRACT FROM AUTHOR]

[Display omitted] • Microbial overlap in biowaste workers' exposure via air and species on hands. • Biowaste links to lactic acid bacteria and compost to A. fumigatus exposure. • Some species have previously been linked to occupational health issues. • Several risk class 2 species present; most species cannot be risk evaluated. • Different species compositions in various particle size fractions. This study aims to investigate the microbiological working environment of biowaste workers, focusing on airborne fungal and bacterial species exposure, size distribution, and species on workers' hands. The research, conducted across six plants with 45 personal exposure assessments, revealed a total of 150 bacterial species and 47 fungal species on workers' hands, including 19 and 9 species classified in risk class 2 (RC2), respectively. Workers' exposure analysis identified 172 bacterial and 32 fungal species, with several in RC2. In work areas, 55 anaerobic bacterial species belonging to RC2 were found. Different species compositions were observed in various particle size fractions, with the highest species richness for anaerobic bacteria in the fraction potentially depositing in the secondary bronchi and for fungi in the pharynx fraction. The geometric mean aerodynamic diameter (D G) of RC2 anaerobic bacteria was 3.9 µm, <1.6 µm for Streptomyces , 3.4 µm for Aspergillus , and 2.0 µm for Penicillium. Overlapping species were identified on workers' hands, in their exposure, and in work areas, with Bacillus amyloliquefaciens, Leuconostoc mesenteroides, Bacillus cereus, Enterococcus casseliflavus , and Aspergillus niger consistently present. While the majority of RC2 bacterial species lacked documented associations with occupational health problems, certain bacteria and fungi, including Bacillus cereus, Escherichia coli, Enterobacter, Klebsiella pneumonia, Aspergillus fumigatus, Aspergillus niger, Aspergillus flavus, Lichtheimia corymbifera, Lichtheimia ramosa, and Paecilomyces variotii, have previously been linked to occupational health issues. In conclusion, biowaste workers were exposed to a wide range of microorganisms including RC2 species which would deposit in different parts of the airways. [ABSTRACT FROM AUTHOR]

Isolation of lactic acid bacteria (LAB) from cheese, pickles, palm wine and yoghurt (fermented foods) were carried out. The LAB were cultivated on De Man Rogosa Sharpe agar and were identified based on their colony and cell morphology, Gram's staining and biochemical tests. The LAB were screened for potential to produce crude bacteriocins in De Man Rogosa Sharpe (MRS) broth using standard techniques. The efficacy of the crude bacteriocins produced by the LAB were tested against Bacillus cereus, Escherichia coli, Pseudomonas aeruginosa and Streptococcus pyogenes. Cheese had the highest LAB counts (3.12×107CFU/g) than other fermented foods analysed. The lactic acid bacteria isolates were probably identified as Lactococcus lactis, Lactobacillus bulgaricus, Leuconostoc mesenteroides and Pediococcus halophilus. Out of the twelve (12) LAB screened for bacteriocin production in MRS broth (in test tubes), six (6) tubes revealed the produced bacteriocins. The result of the efficacy of the crude bacteriocins on the test bacteria showed that Escherichia coli and Streptococcus pyogenes had clear zones of inhibition ranging from 9 to 17mm for Escherichia coli and 9 to 16mm for Streptococcus pyogenes while Bacillus cereus and Pseudomonas aeruginosa were completely resistant to the test bacteriocins. The presence LAB in fermented food products and other food products will enhance preservation (shelf life extension) of the products and still maintain their keeping quality. [ABSTRACT FROM AUTHOR]

This study aims to isolate the freshwater fish–derived potential probiotics and evaluate their beneficial effects on the growth, immune response, and disease resistance of juvenile zebrafish (Danio rerio). Herein, three strains (Leuconostoc mesenteroides GL-5, Weissella hellenica GJ-1, and Pediococcus claussenii GJ-3) were identified with antagonistic activity against fish pathogens, high tolerance to 0.1% bile salt, and good hydrophobicity. As the model, zebrafish (15 days post-fertilization, dpf) were fed with a basal diet (control) supplemented with GL-5, GJ-1, GJ-3, heat-killed Leuconostoc mesenteroides GL-5*, and commercial probiotics (positive control) at a concentration of 1 × 107 CFU/mL for 4 weeks. Compared with the GL-5* (36.35 ± 2.03 mg fish−1) and control (37.31 ± 1.91 mg fish−1) groups, the GL-5 (58.15 ± 2.58 mg fish−1), GJ-1 (69.55 ± 3.85 mg fish−1), GJ-3 (62.90 ± 2.99 mg fish−1), and commercial probiotic (62.03 ± 2.68 mg fish−1) treatment were found to significantly promote the growth of zebrafish. Compared to the control group challenged by immersion with 1 × 107 CFU/mL Aeromonas hydrophila, the GJ-3 and positive groups showed the highest transcript levels of IL-1β and TNF-α at 8 h post-challenge (P < 0.05). The survival rates (80%) of the GJ-3 and commercial probiotic–fed groups were significantly higher than that of the control group (50%) at 32 h post-challenge (P < 0.05). Therefore, Pediococcus claussenii GJ-3 can be considered a potential probiotic for reducing the use of antibiotics and preventing bacterial diseases in fish. [ABSTRACT FROM AUTHOR]

This study investigates microbial biodiversity, with a specific focus on yeast and lactic acid bacteria (LAB), within Sinjai's local minas drinks. The primary goal is to characterize the microbial composition of minas and assess the potential of these microorganisms as starters for porang flour fermentation. This fermentation is carried out to improve the quantity and quality of porang flour, especially for enhancing glucomannan. The identification results from five isolates revealed the presence of two distinct LAB species, Leuconostoc mesenteroides and Weissella cibaria, with a percent identity falling within the 98-99% range, hence indicating a close genetic relationship within each species. Molecular identification further identified two yeast types, Candida tropicalis and Pichia kudriavzevii, thereby demonstrating a high degree of similarity with a percent identity ranging between 98-99%. Analysis of the fermentation treatment indicated a glucomannan production range of 80-91%. Notably, the Pichia kudriavzevii + Leuconostoc mesenteroides + amylase treatment stood out, hence producing the highest glucomannan levels at 91.5%. Calcium oxalate levels in the fermentation treatment ranged from 0.03-0.08%, with the Pichia kudriavzevii + Leuconostoc mesenteroides + amylase treatment proving to be the most effective in reducing calcium oxalate levels to 0.32%. These findings offer valuable insights into optimizing porang flour fermentation processes, thereby emphasizing the significance of specific microbial combinations for enhanced glucomannan production and reduced calcium oxalate content. [ABSTRACT FROM AUTHOR]

A strain of Leuconostoc mesenteroides HDE-8 was isolated from homemade longan fermentation broth. The exopolysaccharide (EPS) yield of the strain was 25.1 g/L. The EPS was isolated and purified, and the structure was characterized using various techniques, including X-ray diffraction (XRD), nuclear magnetic resonance (NMR) spectroscopy, Fourier-transform infrared (FT-IR) spectroscopy, high-performance size exclusion chromatography (HPSEC), and scanning electron microscopy (SEM). The monosaccharide composition of the EPS was glucose, with a molecular weight (Mw) of 1.7 × 106 Da. NMR spectroscopy revealed that the composition of the HDE-8 EPS consisted of D-glucose pyranose linked by α-(1→4) and α-(1→6) bonds. The SEM analysis of the EPS showed an irregular sheet-like structure. Physicochemical analysis demonstrated that EPSs exhibit excellent thermal stability and high viscosity, making them suitable for fermentation in heat-processed and acidic foods. Additionally, milk coagulation tests showed that the presence of EPSs promotes milk coagulation when supplemented with sucrose. It suggests that EPSs have wide-ranging potential applications as food additives, improving the texture and taste of dairy products. This study provides practical guidance for the commercial use of HDE-8 EPSs in the food and related industries. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the probiotic potential of lactic acid bacteria (LAB) isolated from Minas artisanal cheese produced in Campo das Vertentes, MG, and to select bacteria for the production of fermented milk. The following strains, including Lactiplantibacillus plantarum (LPL), Levilactobacillus brevis (LB), Latilactobacillus curvatus (LC), Laticaseibacillus paracasei (LPR), Lactococcus garvieae (LG), Lactococcus lactis (LL), Leuconostoc mesenteroides (LM001), and Leuconostoc pseudomesenteroides (LPS), were assessed for their tolerance to artificial gastric acid and bile salts, susceptibility to antimicrobials, and antagonistic properties. Leuc. mesenteroides (LM001) survived the simulation of gastrointestinal barriers, displayed susceptibility to ten of the 12 antimicrobials tested, and exhibited the ability to inhibit pathogenic microorganisms. Consequently, it was selected for production of fermented milk, which was submitted to physicochemical and microbiological analyses for up to 14 days of storage, yielding results in accordance with current Brazilian legislation. It is recommended that in vivo tests be conducted to assess the probiotic characteristics of Leuc. mesenteroides LM001 for its use in functional foods. [ABSTRACT FROM AUTHOR]

A two-step optimization protocol was attempted to optimize the condition for dextran production from pineapple waste using Leuconostoc mesenteroides NCIM-2198. Response surface methodology, in combination with numerical optimization technique, was explored for this purpose. In the first step, the initial medium pH (6.5–7.5), incubation temperature (25–35 °C), and time (12–60 h) were optimized from 45 full factorial runs. The maximum dextran yield was estimated as 1.46 g·[100 mL]−1 while incubated at 29.2 °C for 57.2 h at an initial pH of 7.15. Further, sucrose concentration (2–10 g·[100 mL]−1) and culture volume (3–7 mL·[100 mL]−1) were optimized from 15 experimental runs. The maximum dextran yield (1.47 g·[100 mL]−1) was obtained at 7.6 g·[100 mL]−1 of sucrose with 3 mL·[100 mL]−1 of culture volume at the previously optimized fermented broth. The response surface models were validated to explain the interaction between factors affecting dextran yield. The structural characteristics of the exopolysaccharide were analyzed. Fourier-transform infrared spectra showed that the exopolysaccharide contains similar spectral peaks as that of standard dextran. Nuclear magnetic resonance spectroscopy confirms the exopolysaccharide was dextran with mainly α-1-6 glycosidic bonds. Scanning electron microscopy explained its porous structure, which would be useful in retaining water and thus giving texturizing and viscosifying properties. [ABSTRACT FROM AUTHOR]

Fermented foods containing probiotic Leuconostoc mesenteroides 201607 (LM) were used to extract exopolysaccharides. An incomplete understanding exists regarding the immunomodulatory characteristics of exopolysaccharides (EPSs), which are important constituents of bacterial biofilms. In this instance, we examined the immunomodulatory capacity of EPSs from fermented food extracted from L. mesenteroides 201607. Partially purified exopolysaccharide from L. mesenteroides 201607 (PP-LMEPS) consists of glucose (57.1%), rhamnose (29.53%), and galactose (13.36%). The maximum EPS yield was attained after 30 h of incubation at 37 °C and an initial pH of 7.0. When lipopolysaccharide-stimulated RAW264.7 was exposed to PP-LMEPS, the inflammatory cytokines were considerably decreased or elevated dose-dependently. Upon the exposure of lipopolysaccharide-stimulated RAW264.7 cells to PP-LMEPS, a dose-dependent modulation of inflammatory cytokines was observed. This suggests that the extracted EPS possesses immunomodulatory characteristics, as evidenced by a significant decrease or increase in inflammatory cytokine levels. However, further research is warranted to fully elucidate the precise mechanisms and potential therapeutic implications of the immunomodulatory properties of PP-LMEPS. [ABSTRACT FROM AUTHOR]

Simple Summary: The Vairimorpha ceranae prevalence and the temperature were surveyed and recorded at the National Chung Hsing University apiary for one year. A positive correlation was found between V. ceranae and temperature, suggesting that the prevalence or activity of V. ceranae increases as temperatures rise. Furthermore, the anti-microsporidia activity of the lactic acid bacteria Leuconostoc mesenteroides TBE-8 against V. ceranae was assessed for the management of microsporidiosis. Microsporidiosis, which is caused by the pathogen Vairimorpha ceranae, is a prevalent disease in the honey bee (Apis mellifera) and might lead to significant adult honey bee mortality. In this study, we conducted an annual survey of the mature spore load of V. ceranae in the guts of nurse bees and forager bees in the apiary of National Chung Hsing University (NCHU) in Taiwan. The results indicated that, on average, honey bees hosted approximately 2.13 × 106 mature spore counts (MSCs)/bee in their guts throughout the entire year. The highest number of MSCs was 6.28 × 106 MSCs/bee, which occurred in April 2020, and the lowest number of MSCs was 5.08 × 105 MSCs/bee, which occurred in November 2020. Furthermore, the guts of forager bees had significantly higher (>58%) MSCs than those of nurse bees. To evaluate the potential of the probiotic to treat microsporidiosis, the lactic acid bacterium Leuconostoc mesenteroides TBE-8 was applied to honey bee colonies. A significant reduction (>53%) in MSCs following probiotic treatment was observed, indicating the potential of probiotic treatment for managing microsporidiosis. This research provided information on V. ceranae MSCs in the honey bee gut at NCHU in Taiwan and the MSCs' correlation with the annual season. Furthermore, a potential probiotic treatment for microsporidiosis was assessed for future management. [ABSTRACT FROM AUTHOR]

BACKGROUND: Volatile organic compounds (VOCs) produced during meat storage are mainly derived from the decomposition of meat components and the metabolism of spoilage bacteria. VOCs produced in sterile bacon model substrate inoculated or un‐inoculated with spoilage bacteria, Staphylococcus xylosus (P2), Leuconostoc mesenteroides (P6), Carnobacterium maltaromaticum (P9), Leuconostoc gelidum (P16) and Serratia liquefaciens (P20), previously isolated, were identified by headspace solid‐phase microextraction (HS‐SPME) coupled with gas chromatography–mass spectrometry (GC–MS). Furthermore, combinations of the strains (Pm) were also obtained. RESULTS: In total, 54 volatile compounds, including aldehydes, alcohols, phenols, ketones, alkanes, alkanes, organic acids, esters and so forth, were determined after 45 days of storage in bacon inoculated with potential spoilage bacteria using the HS‐SPME/GC–MS method. VOC concentrations of alcohols and organic acids in groups inoculated with bacteria were remarkably higher (P < 0.05) compared to that in control samples. Specifically, some VOCs are closely related to the metabolic activity of the inoculated bacterial strains; for example, 2,3‐butanediol was associated with P2, P16 and P20, and acetic acid was mainly related to P6 and P9. CONCLUSION: The results of partial least squares regression indicated that there was a high correlation between the electronic nose sensors and VOCs of smoked inoculated potential spoilage bacteria. These compounds are potentially important for predicting deterioration of smoked bacon. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

There has been an increasing interest in biocatalysts over the past few decades in order to obtain high efficiency, high yield, and environmentally benign procedures aiming at the manufacture of pharmacologically relevant chemicals. Lactic Acid Bacteria (LAB), a microbial group, can be employed as biocatalysts while performing asymmetric reduction of prochiral ketones. In this study, Leuconostoc mesenteroides N6 was used for the asymmetric bioreduction 1-indanone. And then, a novel and innovative face-centered design-based multi-objective optimization model was used to optimize experimental conditions. Also, the experimental design factors were defined as agitation speed, incubation period, pH, and temperature for optimization to acquire the maximum enantiomeric excess (ee) and conversion rate (cr) values. When using the face-centered design-based multi-objective optimization model, the optimum culture conditions corresponded to 96.34 and 99.42%, ee and cr responses, respectively, were pH = 5.87, incubation temperature = 35 °C, incubation period = 50.88 h, and agitation speed = 152.60 rpm. Notably, the validation experiment under the optimum model conditions confirmed the model results. This study demonstrated the importance of the optimization and the efficiency of the face-centered design-based multi-objective model. [ABSTRACT FROM AUTHOR]

This study explored the physicochemical properties and prebiotic activities of glucans and oligoglucans. Oligoglucans were obtained through the fermentation of Leuconostoc mesenteroides CICC6055 and the glucansucrase of strain CICC6055, while glucans were obtained only through fermentation. Thin-layer chromatography and high-performance liquid chromatography identified enzymatically synthesized oligoglucans with a higher yield. Differential scanning calorimetry and derivative thermogravimetry analyses revealed the heat resistance of the glucans and oligoglucans at 280–300 °C. Fourier transform-infrared spectroscopy and nuclear magnetic resonance analyses demonstrated that their main chains were linked with α-1,6-glycosidic bonds accompanied by glucose residue branching. In vitro fermentation experiments demonstrated that they not only improved the contents of short-chain fatty acids but also raised the abundance of predominant flora, such as Bacteroides, Firmicutes, Verrucomicrobia, and Proteobacteria. These results implicate glucansucrase as an efficacious tool for the enzyme synthesis of oligoglucans. Furthermore, both polysaccharides with different degrees of polymerization may be beneficial in maintaining a healthy human gut. [ABSTRACT FROM AUTHOR]

Summary: The fermented vegetable is a long‐history food, and the addition of probiotics in recent years has pushed it in a novel direction. This study explored the impact of a direct‐vat set (DVS) starter, comprising Lactiplantibacillus plantarum MC14 and Leuconostoc mesenteroides, on pickled radish (PR). The addition of DVS triggered a rapid reduction in pH and titratable acidity, leading to lowered nitrite levels and increased viable count. Textural analysis showed that DVS increased the springiness and chewiness of PR by about 55.07% and 25.73%, respectively. Organic acid analysis unveiled eight compounds. The addition of probiotics did not significantly affect the antioxidant properties but was able to significantly enhance the XO inhibitory activity of PR. DVS decreased undesirable flavour compounds such as isothiocyanates and sulphides, while elevating esters, aldehydes and acids. Our results suggested that DVS is a promising starter culture that can enhance the texture and flavour of fermented vegetables. [ABSTRACT FROM AUTHOR]

Exploration of biodiversity led towards the development of commercially important biological metabolites. This study focus on the molecular characterization of dextransucrase biosynthezing lactic acid bacterial strain, L. mesenteroides KIBGE-IB40. Fermentation system was designed to optimize the crucial production parameters of the biosynthesis of dextransucrase by L. mesenteroides. Data acquired from the experimental analysis revealed a significant increase of about 1.69-fold in enzyme titer from 67.13 DSU/ml to 114.04 DSU/ml. The optimum fermentation conditions were found to be fermentation time, 18 hours; fermentation temperature, 25°C; fermentation pH, 7.5. Structural analysis of purified dextran was performed. The morphological analysis of dextran by SEM revealed a porous structure of the polysaccharide. FTIR analysis demonstrates the functional group analysis of the polymer. The significant increase in dextransucrase yield demonstrates the crucial impact of fermentation conditions on the metabolic properties of microbial cells. The obtained results demonstrate a practical approach for the commercial application of L. mesenteroides KIBGE-IB40 dextransucrase in food and other industrial sectors. [ABSTRACT FROM AUTHOR]

Pickled Chinese cabbage traditional fermented vegetables is popular in China, especially the northeast, owing to their special flavors. Spontaneous fermented Chinese cabbage usually has rich and mellow flavor because of abundant microorganism in the fermentation broth. In our study, LAB were screened from spontaneous Chinese cabbage and identified including morphology, physiology and biochemistry, and molecular levels. 11 of these were used as a single inocula to ferment Chinese cabbage, and acid contents, soluble sugar contents, Vc contents, cellulose contents and nitrite contents of these pickled Chinese cabbage were measured. Overall, three superior strains mixture(X1, M2, and D2) were inoculated to improve the fermentation characteristics of pickled Chinese cabbage. Furthermore, pickled Chinese cabbage with the mixture had the highest acid and Vc contents, the lowest nitrite content, and medium fiber content. The sensory quality mixed inocula was also the best compared with products prepared with single strain and spontaneous fermentation. [ABSTRACT FROM AUTHOR]

The DSR-IBUN dextransucrase produced by Leuconostoc mesenteroides strain IBUN 91.2.98 has a short production time (4.5 hours), an enzymatic activity of 24.8 U/mL, and a specific activity of purified enzyme 2 times higher (331.6 U/mg) than that reported for similar enzymes. The aim of this study was to generate a structural model that, from an in silico approach, allows a better understanding, from the structural point of view, of the activity obtained by the enzyme of interest, which is key to continue with its study and industry application. For this, we translated the nucleotide sequence of the dsr_IBUN gene. With the primary structure of DSR-IBUN, the in silico prediction of physicochemical parameters, the possible subcellular localization, the presence of signal peptide, and the location of domains and functional and structural motifs of the protein were established. Subsequently, its secondary and tertiary structure were predicted and a homology model of the dextransucrase under study was constructed using Swiss-Model, performing careful template selection. The values obtained for the model, Global Model Quality Estimation (0.63), Quality Mean (−1.49), and root-mean-square deviation (0.09), allow us to affirm that the model for the enzyme dextransucrase DSR-IBUN is of adequate quality and can be used as a source of information for this protein. [ABSTRACT FROM AUTHOR]

Some lactic acid bacteria (LAB) are capable of producing exopolysaccharides (EPS), which can be used in the dairy industry to reduce syneresis and improve the viscosity and texture of fermented products. The aim of the present study was to screen the EPS-producing capacity of 123 LAB strains isolated from fermented foods to search for those able to produce EPS with the optimal technological aptitude to be applied in non-fat set yogurt manufacture. They were grown on MRS-sucrose and assigned to ropy or mucoid phenotype depending on the appearance of the colonies. Twenty-five of them were selected and assayed for production of both cell-bound EPS (EPS-b) and EPS released to the medium (EPS-r). Those resulting in the most EPS producers (Levilactobacillus brevis UCLM-Lb47, Leuconostoc mesenteroides subsp. mesenteroides 6F6-12 and Leuconostoc mesenteroides subsp. mesenteroides 2F6-9) were used to manufacture non-fat set yogurts. These yogurts were analyzed for microbiological and physicochemical properties (pH, titratable acidity, total solids), water-holding capacity, apparent viscosity, and sensory characteristics during a 28-day cold storage period. The yogurts made with the selected strains showed higher values of water-holding capacity, EPS concentration, and viscosity in the mouth than the control yogurt, which presented a more fluid texture. The results obtained suggest that the three selected strains could be used to replace hydrocolloids in non-fat set yogurt formulation, obtaining a clean-label product that would improve consumer acceptance. [ABSTRACT FROM AUTHOR]

The objectives of this study were to optimize the medium and culture conditions using a strong γ-aminobutyric acid (GABA) producer as a reference lactic acid bacterial strain, to screen and identify GABA-producing lactic acid bacterial isolates from kimchi, and to determine their extracellular GABA-producing abilities. Thin-layer chromatography was used to screen GABA-producing bacterial isolates and highperformance liquid chromatography was used to evaluate the bacterial GABA production abilities. Species-specific polymerase chain reaction analyses were used to identify GABA-producing bacterial isolates. The optimal medium and culture conditions were found to be the modified Man–Rogosa–Sharpe (MRS) broth (with an initial pH of 6.5) containing 4% sucrose, 5% glutamate, and 1% yeast extract at 37 °C for 5 days. After incubation under the optimized culture conditions, 217 kimchi bacterial isolates were screened to evaluate their respective GABA-producing abilities. Screening the 217 kimchi bacterial isolates identified 24 GABA-producing lactic acid bacterial isolates (11%): Lactobacillus plantarum (17), Lactobacillus brevis (six), and Leuconostoc mesenteroides (one), indicating that only a small proportion of the strains produce GABA in the culture broth. The extracellular GABA-producing abilities of the bacterial strains identified in this study varied even within the same species, ranging from 5.8 to 101.7 mM among the 17 GABA-producing L. plantarum isolates and from 8.5 to 88.6 mM among the six GABA-producing L. brevis isolates. In summary, three species of the 24 kimchi GABA-producing bacterial isolates were identified, including one rare species (L. mesenteroides) and the two most dominant species (L. brevis and L. plantarum). [ABSTRACT FROM AUTHOR]

Fermentation has been used as a simple technique for preserving vegetables since ancient days. This research work aimed to isolate, characterize, and identify wild Lactobacillus plantarum found in a brine solution (8% w/v NaCl) of naturally fermented cucumber. Cucumber samples were naturally fermented at ambient temperature for 14 days in a brine solution, in which lactic acid bacteria (LAB) were then cultured (37℃, 48 h) within 24 h for 3, 5, 7, 10, and 14 days. Seventeen different LAB strains were isolated and identified within the different time intervals of fermentation using morphological, biochemical API 50 CHL, PCR verification using Lactobacillus subspeciesspecific genes primer, and 16S rRNA gene sequencing. The API confirmed strains were further verified by PCR to be L. plantarum subsp. plantarum M23 based on the amplified gene fragment separation by gel electrophoresis and gene sequencing. After 24 h of fermentation, the most dominant LAB-identified strains were Leuconostoc mesenteroides, Tetragenococcus halophilus, and L. plantarum M23, respectively. Starting from the fifth day of fermentation, L. plantarum M23 controlled the fermentation process as the dominant LAB. The drop in the pH value was significant (from 6.8 to 3.18) due to the variations in the LAB strains throughout the 14 days of fermentation. Further investigation will be carried out to study the production of plantaricin, which has great importance in food biopreservation. [ABSTRACT FROM AUTHOR]

Introduction: Organic meat products are well known for their probiotic values due to the presence of probiotic lactic acid bacteria such as Lactobacillus, Leuconostoc, Lactococcus, and Pediococcus strains. The present study aimed to isolate and characterize new strains of lactic acid bacteria (LABs) from organic meat sausages and evaluate their antimicrobial activities. Materials and Methods: In this study, LAB strains were isolated from vacuum-packed organic meat sausages bought from Solico Group Co Ltd. (Tehran, Iran). All isolates were characterized by morphological, biochemical, and 16S rRNA analysis. The primary antibacterial activity of the isolates was evaluated against Micrococcus luteus PTCC 1408. The growth kinetics and antimicrobial activity of the strain MN-B against Lactobacillus casei ATCC 39392 were determined in an MRS broth medium. In addition, a bacteriocin produced by the strains MN-B revealed antimicrobial activity against selected foodborne pathogens. Bacteriocin produced by the MN-B strain was partially purified using the adsorption-desorption method followed by dialyzes. Results: In this study, two Pediococcus spp. and three Leuconostoc spp. with antimicrobial activity were isolated from vacuum-packed organic meat sausages and designated as MNA, MN-B, MN-A2, MN-A2-1, and MN-A3. The results showed that the isolate MN-A and MN-B belonged to the strain Pediococcus acidilactici and the MN-A2, MN-A2-1, and MN-A3 isolates were identified as Leuconostoc mesenteroides strains. Amongst the isolates, the strain MN-B showed the highest antimicrobial activity against the Micrococcus luteus PTCC 1408. The molecular weight of bacteriocin was about 5.0 KDa. Discussion and Conclusion: Pediococcus acidilactici (strain MN-B) showed significant antimicrobial activity against Salmonella enterica subsp. enterica serotype Typhimurium PTCC 1709, Staphylococcus aureus PTCC 1113, Listeria monocytogenes PTCC1302, and Listeria inovani PTCC 1303. Therefore, this strain can be considered a potential candidate in different sectors such as the food industry as a preservative. [ABSTRACT FROM AUTHOR]

Elaeocarpus sylvestris, an evergreen tree widely distributed in Jeju Island, South Korea, contains polyphenolic compounds (phenols and flavonoids) exhibiting antioxidant, antiviral, and antibacterial activities. This study examines the antimicrobial, antioxidant, and cytotoxicity profiles of E. sylvestris extracts. Leaf extract (LE) and branch extract (BE) of E. sylvestris obtained using 60% methanol were filtered and concentrated. The antimicrobial efficacy of these extracts against foodborne pathogens and lactic acid bacteria was examined. The antioxidant property was tested along with assays to assess cytotoxicity and effects on cell proliferation. The extracts were also subjected to antioxidant assays and tested for cytotoxicity and effects on cell proliferation using human skin fibroblasts (Detroit 551). LE completely inhibited the growth of Staphylococcus aureus and Listeria monocytogenes at 100 mg/mL. Seven strains of lactic acid bacteria were susceptible to the whole extracts. LE significantly suppressed the growth of Weisella confusa, Pediococcus acidilactici, and Leuconostoc mesenteroides (p < 0.05). Yeasts (Pichia anomala and Pichia fermentans) exhibited significantly higher growth rates than lactic acid bacteria. Both extracts (100 mg/mL) significantly decreased H2O2 formation (>50%). The confluency of Detroit 551 cells was 68.07–87.52% at concentrations of 0–50 μg/mL for 24 h. In total, 130 metabolites were identified in BE and 128 in LE, including metabolites with potential benefits for skin improvement and photoprotection. A methanolic extract of E. sylvestris could be a promising source of natural bioactive materials for both microbial biocontrol and functional skin care cosmetics, with a wide range of applications in the food, cosmetic, and pharmaceutical industries. [ABSTRACT FROM AUTHOR]

Food allergy (FA) is acknowledged as a significant public health and food safety issue, due to its manifestation as an amplified immune reaction to food antigens. Recently, probiotics within Lactobacillus and Bifidobacterium have been highlighted as a promising strategy against allergic disease by modulating the balance of Th1/Th2 responses. However, the allergy‐alleviating effects of probiotic Leuconostoc mesenteroides strains are unknown. Therefore, this study investigated the potentials of eleven L. mesenteroides strains on the Th1/Th2 balance in vitro by evaluating the expression patterns of interferon‐gamma (IFN‐γ) (Th1 cytokine) and interleukin‐4 (IL‐4) (Th2 cytokine) in mesenteric lymph node‐derived lymphocytes from ovalbumin (OVA)‐sensitized mice. Among strains, WHH1141 incubation caused the highest IFN‐γ/IL‐4 ratio. Oral administration of WHH1141 (1 × 109 CFU/mL) in the OVA‐induced FA mouse model for 40 days improved the weight loss and FA pathological symptoms and normalized the serum immunoglobulin E levels. Meanwhile, the OVA‐induced elevated gene expressions of cytokines (IL‐4, IL‐5, and IL‐13) and tight‐junction proteins (ZO‐1 and Occludin) and levels of cytokines (IL‐4, IL‐5, and IL‐13) and histamine in the jejunum were restored by WHH1141. Furthermore, WHH1141 reversed the reduced gut microbial diversity and short‐chain fatty acid (SCFA) levels, specifically increased Bacteroidota abundance, and decreased Firmicutes abundance in OVA‐induced mice. Overall, these findings suggest that WHH1141 exerts FA‐alleviating effects on OVA‐induced mice, which is involved with the inhibition of the jejunal Th2 immune responses and the modulation of gut microbiome composition and SCFA productions. Practical Application: Leuconostoc mesenteroides WHH1141 with FA‐alleviating potentials may be considered a promising approach in the mitigation of FA symptoms. [ABSTRACT FROM AUTHOR]

Fungal growth impair strongly the quality of processed cocoa, leading to low crops value for farmers and manufacturers. The antifungal activity of lactic acid bacteria (LAB) from fermenting cocoa was analyzed and the conditions of fungal inhibition were evaluated. Fungi were isolated from stored fermented and dried cocoa beans on sabouraud plate medium. The results showed that, LAB strongly inhibit fungi isolated from fermented cocoa beans notably Mucors and Aspergilli, with Lactobacillus plantarum inducing the stronger inhibition whereas Leuconostoc mesenteroides produced a weaker inhibition. Acids production assayed by HPLC was found to be not related to antifungal activity, since LAB strains producing strong antifungal activity were not necessarly the best acid producers. Maximum fungal inhibition occured at 35 °C in Lactobacillus plantarum and Leuconostoc mesenteroides but also at 30 °C in Lactobacllus casei. Likewise, a narrow acidic pH range (3.0-4.0) allowed full expression of fungal inhibtion in LAB analyzed that decreased progressively toward pH 7.0 and failed at alkalin pH. However, sucrose even at high content (8%) was found to have no effect on antifungal activity of LAB, but its bioconversion product glucose and fructose decreased this activity when concentrations were set at 6 et 2 %, respectively. All together, the results suggest that, LAB may effectively exert fungal inhibition in a narrow timing of cocoa fermentation, with pulp contained sugars as metabolic regulators of this inhibition. These results may contribute to a better management of LAB as starter culture for an efficient inhibition of fungal growth and prevention of cocoa contamination from mycotoxins. [ABSTRACT FROM AUTHOR]

Grapevine crown gall, caused by Allorhizobium vitis (A. vitis) and fire blight, caused by Erwinia amylovora (E. amylovora) of rosaceous plants, have been recognized as serious bacterial diseases and responsible for major crop losses in grapevine (Vitis vinifera L.), pear (Pyrus communis L.) and apple (Malus domestica Borkh.) worldwide. To develop an effective biocontrol method against the two bacterial pathogens, lactic acid bacteria (LAB) isolated from agricultural irrigation canals were tested as biocontrol agents. Thirty-two bacterial isolates were screened for their in vitro antagonistic activity. Four isolates (MS-1, MS-2, MS-3, and MS-4), identified by partial sequencing of 16S rRNA as Leuconostoc mesenteroides subsp. Jonggajibkimchii, were found to significantly inhibit the growth of A. vitis and E. amylovora in vitro. The biocontrol efficiency of these strains was tested against E. amylovora on immature pear fruits under laboratory conditions, and against A. vitis in tomato (Solanum lycopersicum L.) and kalanchoe (Kalanchoe daigremontiana) plants, under greenhouse conditions. Results showed that all selected antagonists were able to suppress fire blight disease on immature pear fruits. On tomato plants, the MS-1 and MS-2 strains were able to reduce the A. vitis infection by 82% and 99%, respectively. Similarly, the MS-2 strain reduced gall formation on kalanchoe plants by 99%. We concluded that Leuconostoc mesenteroides subsp. Jonggajibkimchii strains could serve as a potential biocontrol agent against fire blight and grapevine crown gall diseases. [ABSTRACT FROM AUTHOR]

The modification effect of fermentation on the pasting properties of flours enhances their potential as functional ingredients in product development. As such, the fermentation of sweet potato (SP) may alter its pasting properties and thus enhance its application for new food product development. The aim of this study was to determine the effect of starter culture and fermentation time variations on the pasting profile and amylose content of SP flour. The starters used were Leuconostoc mesenteroides, Saccharomyces cerevisiae, and a paired culture of Leuconostoc mesenteroides and Saccharomyces cerevisiae with a fermentation time of 24, 48, 72, and 96 h. Results obtained showed that fermentation starter variation had a significant effect (p < 0.01) on some pasting properties and amylose content of the SP. The highest peak viscosity of 1204 Brabender units (BU) was obtained from samples fermented with the paired culture of Leuconostoc mesenteroides and Saccharomyces cerevisiae. Based on these results, fermented SP flour possesses the potential to be applied to products that require a thickening property. [ABSTRACT FROM AUTHOR]

This study investigated the interactions of four bacteria strains isolated from Yamahai‐shubo, the source of yeast used to produce a Japanese traditional rice wine, Yamahai‐shikomi sake. The bacterial strains were nitrate‐reducing Pseudomonas sp. 61‐02, Leuconostoc mesenteroides LM‐1, Lactiplantibacillus plantarum LP‐2, and Latilactobacillus sakei LS‐4. We examined fermentation factors for Yamahai‐shubo and Yamahai‐shikomi sake samples to compare the suitability of their bacterial combination (16 variations). As a result of principal component analysis, we found that two major groups were formed; one containing strain LP‐2 and the other containing strain LS‐4, and that strains LP‐2 and LS‐4 were important in the Yamahai‐shikomi sake in the presence of strains 61‐02 and LM‐1. Then, we investigated the effects of strains LP‐2 and LS‐4 on the concentration of organic acids (pyruvic acid, citric acid, succinic acid, malic acid, and lactic acid) in Yamahai‐shikomi sake. Only in lactic acid, a tendency to decrease with a smaller proportion of LS‐4 strains in Yamahai‐shubo was observed. Subsequently, their effect on the concentration of diacetyl, crucial for aroma, was investigated between the LP‐2 and LS‐4 strains. The sample prepared in the absence of strain LS‐4 exhibited the lowest concentration of diacetyl. This result was supported by the statistical analysis for the sensory scores performed for aroma of each Yamahai‐shikomi sake sample. In conclusion, strain LP‐2 plays a more significant role in improving Yamahai‐shikomi sake quality with strains LM‐1 and 61‐02 rather than strain LS‐4 in Yamahai‐shubo preparation and Yamahai‐shikomi sake brewing. [ABSTRACT FROM AUTHOR]

Fermentation technology was used to prepare the acaí (Euterpe oleracea) fermentation liquid. The optimal fermentation parameters included a strain ratio of Lactobacillus paracasei: Leuconostoc mesenteroides: Lactobacillus plantarum = 0.5:1:1.5, a fermentation time of 6 days, and a nitrogen source supplemental level of 2.5%. In optimal conditions, the ORAC value of the fermentation liquid reached the highest value of 273.28 ± 6.55 μmol/L Trolox, which was 55.85% higher than the raw liquid. In addition, the FRAP value of the acaí, as well as its scavenging ability of DPPH, hydroxyl, and ABTS free radicals, increased after fermentation. Furthermore, after fermentation treatment, the microstructure, basic physicochemical composition, amino acid composition, γ‐aminobutyric acid, a variety of volatile components, and so on have changed. Therefore, fermentation treatment can significantly improve the nutritional value and flavor of the acaí. This provides a theoretical basis for the comprehensive utilization of acaí. [ABSTRACT FROM AUTHOR]

Lactic acid bacteria have been widely used as probiotics for improving gut health. However, studies on oral probiotics were very limited. In this study, 67 lactic acid bacteria (LAB) were isolated from fermented food and screened for antagonistic activity against Streptococcus mutans, the causative pathogen of dental caries. Leuconostoc mesenteroides MJM60376 showed the highest antagonistic activity against S. mutans KCTC3065. L. mesenteroides MJM60376 also showed oral probiotic characteristics including weak acid production, lysozyme tolerance, adhesion to oral epithelial cell (YD‐38), antibiotic susceptibility, and good coaggregation ability with S. mutans. Furthermore, the biofilm formation of S. mutans was significantly reduced when cocultured with L. mesenteroides. Scanning electron microscopy analysis showed that amounts of attached bacteria of S. mutans and network‐like structures were significantly reduced by L. mesenteroides MJM60376. Cell‐free supernatant (CFS) of L. mesenteroides MJM60376 also greatly inhibited biofilm formation of S. mutans from the adherent stage, the activity remained even after it was treated with catalase, trypsin, or pH neutralized. Expression levels of biofilm formation‐related genes were significantly reduced in S. mutans when it was treated with the CFS of L. mesenteroides MJM60376. Therefore, L. mesenteroides MJM60376 has great potential to be used as a multifunctional ingredient. [ABSTRACT FROM AUTHOR]

Aims The aim of this study was to investigate the dynamics of bacterial communities and natural fermentation quality in three steppe types [meadow steppe (MS); typical steppe (TS); and desert steppe (DS)] on the Mongolian Plateau. Methods and results PacBio single molecule with real-time sequencing technology was applied to provide insights into the dynamics of the physicochemical characteristics and the complex microbiome of native grass after 1, 7, 15, and 30 days of fermentation process. The dry matter, crude protein, and water soluble carbohydrate (WSC) contents of the three groups slowly decreased after 1 day of fermentation process, and the lowest WSC concentration after 30 days of ensiling was detected in the DS group compared to that in the MS and TS groups. There was no significant effect of steppe types on lactic acid and butyric acid content (P  > 0.05). The pH was higher in the early stages of fermentation. After 30 days of fermentation, the pH of MS and DS dropped to ∼5.60, while TS was as high as 5.94. At different ensiling days, the pH of TS was significantly higher than that of MS (P  < 0.05). The ammonia nitrogen content of MS was significantly higher than TS and DS (P  < 0.05). During the whole fermentation process, Leuconostoc mesenteroides and Pseudocitrobacter faecalis were the main species of DS, while Enterobacter roggenkampii and Faecalibacterium prausnitzii dominated the fermentation process in MS and TS, respectively. Conclusions The fermentation quality of native grass silage of different steppe types was less satisfactory, with the silage quality ranging from DS, MS, and TS in descending order. The epiphytic bacteria dominating the fermentation process differed between steppe types of silage. Leuconostoc mesenteroides as the main strain of DS had a modulating effect on pH and LA content, while the main strains of MS and TS (Enterobacter roggenkampii and Faecalibacterium prausnitzii) dominated the silage without significant effect on improving fermentation characteristics and nutritional quality. [ABSTRACT FROM AUTHOR]

The ripening of cheese, caused by the combined effect of the fermentative enzyme and microflora of the bacterial starter, occurs in certain intervals of temperature, humidity and acidity of the environment which depend on the type of cheese. The composition of bacterial starters for hard cheese is important for formation of the finished product properties and affects the choice of technological regimes. Even minor changes in ripening conditions can significantly affect the microbiological, physicochemical, biochemical parameters, organoleptic properties, and safety of the target product. The aim of the investigation was to study the influence of ripening temperature regimes on the physicochemical, biochemical and organoleptic characteristics of hard cheeses with a low temperature of the second heating aged 30 days, produced using different compositions of bacterial starters. It was shown that the inclusion of lactobacilli Lactobacillus casei in the composition of the bacterial starter "Active" makes it possible to intensify proteolysis, and the using of aroma-forming lactic acid bacteria Leuconostoc mesenteroides in the starter culture "Active-LN" has a positive effect on the formation of the taste-aromatic composition and texture of the cheese. Changes in the microbiological parameters of cheeses at different stages of production were monitored and the sanitary and hygienic properties of the finished products were evaluated. It was established that cheeses produced both with the use of starter cultures "Active" and "Active-LN" had been ripened best at a temperature of 12–13°C. The products had a good taste and aroma with distinctive features of each type of cheese microbiota, a plastic consistency and a pattern with correctly shaped eyes, larger in cheese with "Aktiv-LN". Thus, the temperature 12–13°С and humidity 75–85% are adequate for the ripening of these cheeses and ensure the formation of a specific taste and aromatic composition of the products and the required level of maturation during 30 days. [ABSTRACT FROM AUTHOR]

The aim of this work was to use consortia (two or three strains) of lactic acid bacteria (LAB) [Lactiplantibacillus plantarum CRL 1964 and CRL 1973, and Leuconostoc mesenteroides subsp. mesenteroides CRL 2131] to obtain quinoa sourdoughs (QS) for further manufacturing of quinoa sourdough-based biscuits (QB). Microbial grow and acidification were evaluated in QS while antioxidant activity (AOA), total phenolic compounds (TPC) and total flavonoid compounds (TFC) were determined in QS and QB. QS inoculated with LAB consortia respect to monocultures showed higher growth and acidification, AOA (7.9?42.6%), TPC (19.9?35.0%) and TFC (6.1?31.6%). QB prepared with QS inoculated by LAB consortia showed higher AOA (5.0-81.1%), TPC (22.5?57.5%) and TFC (14.0-79.9%) than biscuits inoculated by monocultures sourdoughs. These results were attributed to a synergic effect from LAB consortia. Principal component analysis showed the highest scores of the evaluated characteristics for biscuits made with consortia sourdough of two (CRL1964?+?CRL2131) and three (CRL1964?+?CRL1973?+?CRL2131) strains. [ABSTRACT FROM AUTHOR]

Fructophilic Lactic Acid Bacteria (FLAB), Fructobacillus fructosus DPC7238 and pseudofructophilic Leuconostoc mesenteroides DPC7261 and non-FLAB Limosilactobacillus reuteri DSM20016 strains were studied for their growth and morphological evolution as a function of increased fructose concentrations (0, 25, and 50% w/v) in the media. A comparison of the genomics of these strains was carried out to relate observed changes and understand fructose-rich adaptations. The viability of FLAB strains were reduced by approx. 50% at a 50% fructose concentration, while the Limosilactobacillus reuteri strain was reduced to approx. 98%. Electron microscopy demonstrated that FLAB strain, Fructobacillus. fructosus and pseudofructophilic Leuc. mesenteroides, were intact but expanded in the presence of high fructose in the medium. Limosilactobacillus reuteri, on the other hand, ruptured as a result of excessive elongation, resulting in the formation of cell debris when the medium contained more than 25% (w/v) fructose. This was entirely and quantitatively corroborated by three-dimensional data obtained by scanning several single cells using an atomic force microscope. The damage caused the bacterial envelope to elongate lengthwise, thus increasing width size and lower height. The cell surface became comparatively smoother at 25% fructose while rougher at 50% fructose, irrespective of the strains. Although Fructobacillus fructosus was highly fructose tolerant and maintained topological integrity, it had a comparatively smaller genome than pseudofructophilic Leuc. mesenteroides. Further, COG analysis identified lower but effective numbers of genes in fructose metabolism and transport of Fructobacillus fructosus, essentially needed for adaptability in fructose-rich niches. [ABSTRACT FROM AUTHOR]

We aimed at improving probiotic survival, stability and release in digestive settings during yogurt storage. Alginate–basil seed mucilage was formulated with various concentrations of prebiotics (inulin, fructooligosaccharides and fenugreek) and selected for microencapsulation. When compared with uncapsulated probiotic cells, all examined formulations had high encapsulation effectiveness of over 98.2% and a viable potential probiotic cell survival (62%) when studied under simulated settings. These findings indicate the use of home‐grown‐based gums such as basil seed adhesive and fenugreek in combination with alginate are good media for probiotic encapsulation. [ABSTRACT FROM AUTHOR]

The large application potential of microbiomes has led to a great need for mixed culture methods. However, microbial interactions can compromise the maintenance of biodiversity during cultivation in a reactor. In particular, competition among species can lead to a strong disequilibrium in favor of the fittest microorganism. In this study, an invert emulsion system was designed by dispersing culture medium in a mixture of sunflower oil and the surfactant PGPR. Confocal laser scanning microscopy revealed that this system allowed to segregate microorganisms in independent droplets. Granulomorphometric analysis showed that the invert emulsion remains stable during at least 24 h, and that the introduction of bacteria did not have a significant impact on the structure of the invert emulsion. A two-strain antagonistic model demonstrated that this invert emulsion system allows the propagation of two strains without the exclusion of the less-fit bacterium. The monitoring of single-strain cultures of bacteria representative of a cheese microbiota revealed that all but Brevibacterium linens were able to grow. A consortium consisting of Lactococcus lactis subsp. lactis biovar diacetylactis, Streptococcus thermophilus, Leuconostoc mesenteroides, Staphylococcus xylosus, Lactiplantibacillus plantarum and Carnobacterium maltaromaticum was successfully cultivated without detectable biotic interactions. Metabarcoding analysis revealed that the system allowed a better maintenance of alpha diversity and produced a propagated bacterial consortium characterized by a structure closer to the initial state compared to non-emulsified medium. This culture system could be an important tool in the field of microbial community engineering. [ABSTRACT FROM AUTHOR]

The industrialisation of Western food systems has reduced the regular consumption of lacto-fermented vegetables (LFV). Consuming LFV may exert health benefits through the alteration of the gut microbiome, but the mechanisms involved remain unclear. To start understanding the possible benefits of LFV, we compared faecal microbial diversity and composition, as well as dietary habits between individuals who regularly consume LFV (n  = 23) and those who do not (n  = 24). We utilised microbial DNA amplicon sequencing (16S rRNA and ITS2) and untargeted metabolomics (LC–MS) to analyse stool samples. Study participants also provided three consecutive days of dietary data. Results show minor effects on microbiome composition; with the enrichment of a few microorganisms potentially associated with vegetable ferments, such as Leuconostoc mesenteroides and Rhodotorula mucilaginosa (P  < 0.05), in LFV consumers. However, LFV consumption had greater effects on the faecal metabolome, with higher abundances of butyrate, acetate, and valerate (P  < 0.05) and significantly greater metabolome diversity (P  < 0.001). Overall, the observations of minor changes in the faecal microbiome and greater effects on the faecal metabolome from LFV consumption warrant further investigations on the health significance of LFV as regular components of the daily diet in humans. [ABSTRACT FROM AUTHOR]

Incorporation of the baobab fruit pulp in innovative formulations remains limited, despite its abundance of various nutrients and bioactive components. The objective of this study was to enhance the utilization of the baobab fruit pulp through the development of baobab supplemented cultured milk products. The physicochemical, microbial characteristics and consumer acceptability of treatments were studied. In the treatments, an increase in baobab pulp concentration led to an increase in some proximate components. A significant increase in the calcium, zinc, and vitamin C content was also observed with increased baobab concentration at different culture concentrations. Formulations were free from pathogenic bacteria and hence safe for human consumption. It was also established that Leuconostoc mesenteroides were responsible for the fermentation of the cultured formulations. Incorporating baobab fruit pulp in milk has proven to have a positive effect on the overall nutritional value of the milk, enhancing its suitability in combating micronutrient deficiencies. [ABSTRACT FROM AUTHOR]

Acetobacterium woodii is known to produce mainly acetate from CO2 and H2, but the production of higher value chemicals is desired for the bioeconomy. Using chain‐elongating bacteria, synthetic co‐cultures have the potential to produce longer‐chained products such as caproic acid. In this study, we present first results for a successful autotrophic co‐cultivation of A. woodii mutants and a Clostridium drakei wild‐type strain in a stirred‐tank bioreactor for the production of caproic acid from CO2 and H2 via the intermediate lactic acid. For autotrophic lactate production, a recombinant A. woodii strain with a deleted Lct‐dehydrogenase complex, which is encoded by the lctBCD genes, and an inserted D‐lactate dehydrogenase (LdhD) originating from Leuconostoc mesenteroides, was used. Hydrogen for the process was supplied using an All‐in‐One electrode for in situ water electrolysis. Lactate concentrations as high as 0.5 g L–1 were achieved with the AiO‐electrode, whereas 8.1 g L–1 lactate were produced with direct H2 sparging in a stirred‐tank bioreactor. Hydrogen limitation was identified in the AiO process. However, with cathode surface area enlargement or numbering‐up of the electrode and on‐demand hydrogen generation, this process has great potential for a true carbon‐negative production of value chemicals from CO2. [ABSTRACT FROM AUTHOR]

Introduction: Organic meat products are well known for their probiotic values due to the presence of probiotic lactic acid bacteria such as Lactobacillus, Leuconostoc, Lactococcus, and Pediococcus strains. The present study aimed to isolate and characterize new strains of lactic acid bacteria (LABs) from organic meat sausages and evaluate their antimicrobial activities. Materials and Methods: In this study, LAB strains were isolated from vacuum-packed organic meat sausages bought from Solico Group Co Ltd. (Tehran, Iran). All isolates were characterized by morphological, biochemical, and 16S rRNA analysis. The primary antibacterial activity of the isolates was evaluated against Micrococcus luteus PTCC 1408. The growth kinetics and antimicrobial activity of the strain MN-B against Lactobacillus casei ATCC 39392 were determined in an MRS broth medium. In addition, a bacteriocin produced by the strains MN-B revealed antimicrobial activity against selected foodborne pathogens. Bacteriocin produced by the MN-B strain was partially purified using the adsorption-desorption method followed by dialyzes.Results: In this study, two Pediococcus spp. and three Leuconostoc spp. with antimicrobial activity were isolated from vacuum-packed organic meat sausages and designated as MNA, MN-B, MN-A2, MN-A2-1, and MN-A3. The results showed that the isolate MN-A and MN-B belonged to the strain Pediococcus acidilactici and the MN-A2, MN-A2-1, and MN-A3 isolates were identified as Leuconostoc mesenteroides strains. Amongst the isolates, the strain MN-B showed the highest antimicrobial activity against the Micrococcus luteus PTCC 1408. The molecular weight of bacteriocin was about 5.0 KDa. Discussion and Conclusion: Pediococcus acidilactici (strain MN-B) showed significant antimicrobial activity against Salmonella enterica subsp. enterica serotype Typhimurium PTCC 1709, Staphylococcus aureus PTCC 1113, Listeria monocytogenes PTCC1302, and Listeria inovani PTCC 1303. Therefore, this strain can be considered a potential candidate in different sectors such as the food industry as a preservative. [ABSTRACT FROM AUTHOR]