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Polyols, or sugar alcohols, are widely used in the industry as sweeteners and food formulation ingredients, aiming to combat the incidence of diet-related Non-Communicable Diseases. Given the attractive use of Generally Regarded As Safe (GRAS) enzymes in both academia and industry, this study reports on an optimized process to achieve polyols transglucosylation using a dextransucrase enzyme derived from Leuconostoc mesenteroides. These enzyme modifications could lead to the creation of a new generation of glucosylated polyols with isomalto-oligosaccharides (IMOS) structures, potentially offering added functionalities such as prebiotic effects. These reactions were guided by a design of experiment framework, aimed at maximizing the yields of potential new sweeteners. Under the optimized conditions, dextransucrase first cleared the glycosidic bond of sucrose, releasing fructose with the formation of an enzyme-glucosyl covalent intermediate complex. Then, the acceptor substrate (i.e., polyols) is bound to the enzyme-glucosyl intermediate, resulting in the transfer of glucosyl unit to the tested polyols. Structural insights into the reaction products were obtained through nuclear maneic resonance (NMR) and matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) analyses, which revealed the presence of linear α(1 → 6) glycosidic linkages attached to the polyols, yielding oligosaccharide structures containing from 4 to 10 glucose residues. These new polyols-based oligosaccharides hold promise as innovative prebiotic sweeteners, potentially offering valuable health benefits.

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]

High incidences of the foodborne pathogen Listeria monocytogenes have been reported on smear cheeses, and despite increased hygiene efforts, this incidence has remained stable in recent years. Applying antilisterial strains may increase the safety of smear cheeses. To find and test antilisterial strains, we inoculated fresh soft cheeses from nine dairies with the surrogate species Listeria innocua and assessed its growth under standardized ripening conditions. Acetic acid at day 23 (r = −0.66), lactose in fresh cheese (r = −0.63), and glucose at day 10 (r = −0.62), as well as seven amplicon sequence variants (ASVs), were negatively correlated with L. innocua growth. Two of these ASVs were assigned to the genus Leuconostoc of Lactobacillaceae (r = −0.82 and −0.71). Isolates from this family, from Aerococcaceae, and Carnobacteriaceae were characterized according to their inhibitory properties, and those showing antilisterial properties were applied as protective cultures in challenge tests. The combined application of strains of Leuconostoc mesenteroides, Aerococcaceae, and Carnobacteriaceae successfully eliminated low levels of L. innocua in the final products. This is likely explained by antimicrobial compounds, including mesentericin Y105 and acetate, and competition for carbon sources and iron. This study shows a promising way to improve the safety of soft smear cheeses by applying defined protective cultures. [ABSTRACT FROM AUTHOR]

Copyright of Science & Technology of Food Industry is the property of Science & Technology of Food Industry Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Alcohol-related hangovers impact both physical and mental wellness, largely due to acetaldehyde levels produced through alcohol metabolism. The present study investigated the efficacy and safety of the Wilac L probiotic complex (Levilactobacillus brevis WiKim0168 and Leuconostoc mesenteroides WiKim0172 isolated from kimchi) in improving hangovers post-alcohol consumption. This study was conducted as a randomized, double-blind, crossover placebo-controlled clinical trial from August 2023 to February 2024. Subjects (n = 26) were randomized into six test groups consuming three products, the Wilac L probiotic complex, Wilac L35 (Wilac L probiotic complex with Pyrus pyrifolia Nakai), or placebo, in different orders with crossover after a wash-out interval of 7–10 days. Blood alcohol and acetaldehyde concentrations were measured 0, 0.25, 0.5, 1, 2, 4, 6, and 15 h after alcohol consumption. The blood acetaldehyde levels measured with Wilac L probiotic complex supplementation were significantly lower than the control at 0.25 (p = 0.0381), 0.5 (p = 0.0498), and 1 h (p = 0.0260) post-consumption. The blood acetaldehyde levels after Wilac L35 consumption compared to the control are significant at 0.25 (p = 0.0115), 0.5 (p = 0.0054), 1 (p = 0.0285), 2 (p = 0.0113), and 6 h (p = 0.0287) post-consumption. No significant adverse events were reported. The Wilac L probiotic complex is associated with decreased blood acetaldehyde levels and improved subjective hangover symptoms. [ABSTRACT FROM AUTHOR]

This study investigated the impact of a transglycosylated product (ACOD) catalyzed by Leuconostoc mesenteroides MKSR dextransucrase using sucrose as a glucosyl donor and both maltose and Artemisia capillaris as acceptors on gut microbiota through fecal fermentation. ACOD promoted the growth of probiotics such as Lactiplantibacillus plantarum, Lacticaseibacillus casei, Lacticaseibacillus rhamnosus GG, and Leuconostoc mesenteroides MKSR, while inhibiting the growth of pathogenic bacteria such as Escherichia coli, E. coli O157:H7, Enterococcus faecalis, Listeria monocytogenes, Staphylococcus aureus, Shigella flexneri, Streptococcus mutans, Pseudomonas aeruginosa, and Bacillus cereus during independent cultivation. Fecal fermentation for 24 h revealed that ACOD significantly increased the production of short-chain fatty acids (SCFAs) compared to the blank and fructoooligosaccharide (FOS) groups. Specifically, ACOD led to a 4.5-fold increase in acetic acid production compared to FOSs and a 3.3-fold increase in propionic acid production. Both the ACOD and FOS groups exhibited higher levels of butyric acid than the blank. Notably, ACOD significantly modulated the composition of the gut microbiota by increasing the relative abundances of Lactobacillus and decreasing Escherichia/Shigella and Salmonella. In contrast, FOSs remarkably promoted the growth of Salmonella. These findings suggest that ACOD is a potential candidate for prebiotics that improve the intestinal environment by being actively used by beneficial bacteria. [ABSTRACT FROM AUTHOR]

The aim of this study was to examine the biological activity and probiotic properties of lactic acid bacteria (LAB) isolated from sweet potato stalk kimchi (SPK). Various LAB and Bacillus spp. are active in the early stages of the fermentation of kimchi made from sweet potato stalk. Four strains of LAB were identified, including SPK2 (Levilactobacillus brevis ATCC 14869), SPK3 (Latilactobacillus sakei NBRC 15893), SPK8 and SPK9 (Leuconostoc mesenteroides subsp. dextranicum NCFB 529). SPK2, SPK3, SPK8, and SPK9 showed 64.64–94.23% bile acid resistance and 78.66–82.61% pH resistance. We identified over 106 CFU/mL after heat treatment at 75 °C. Four strains showed high antimicrobial activity to Escherichia coli and Salmonella Typhimurium with a clear zone of >11 mm. SPK2 had the highest antioxidative potentials, higher than the other three bacteria, with 44.96 μg of gallic acid equivalent/mg and 63.57% DPPH scavenging activity. These results demonstrate that the four strains isolated from sweet potato kimchi stalk show potential as probiotics with excellent antibacterial effects and may be useful in developing health-promoting products. [ABSTRACT FROM AUTHOR]

The aim of this study was to develop an innovative sourdough using dehydrated okra (Abelmoschus esculentus L.) pod flour and to use it in the production of bread. Three different flours (sun-dried S, freeze-dried F, oven-dried O) were individually mixed at 9% with wheat flour (Dough Yield 300) and fermented (N0: 8.0 log10 CFU/g) for 14 h, using Lactiplantibacillus plantarum ITM21B, Weissella cibaria C43-11 or Leuconostoc mesenteroides C43-2M. The results showed that after fermentation, the content of organic acids (lactic, acetic and propionic), exopolysaccharides (EPS), l-glutamic acid and total free amino acids (TFAA) increased and the high molecular weight proteins were converted into smaller proteins. Sourdough based on Leuc. mesenteroides and O flour (O_LeuMes) was selected to evaluate its applicability in bread making. It was included in the yeast-leavened bread formulation at 20 or 40% (0.6% and 1.21% w/w O flour replacement). The results showed that fermentation limited the negative effects of unfermented O flour on bread quality attributes, mainly the specific volume and firmness. Bread with O_LeuMes at 40% was improved in TFAA, EPS and l-glutamic acid content and showed a higher specific volume and lower moisture and firmness compared to bread with the unfermented O flour. [ABSTRACT FROM AUTHOR]

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A Leuconostoc mesenteroides strain (SJC113) isolated from cheese curd was found to produce large amounts of a mucoid exopolysaccharide (EPS). An analysis revealed the glucan nature of the EPS with 84.5% (1→6)-linked α-d-glucose units and 5.6% (1,3→6)-linked α-d-glucose units as branching points. The EPS showed 52% dextranase resistance and a yield of 7.4 ± 0.9 g/L from MRS medium supplemented with 10% sucrose within 48 h. Ln. mesenteroides SJC113 was also characterized and tested for the production of EPS as a fat substitute in fresh cheese. Strain SJC113 showed high tolerance to a wide range of NaCl concentrations (2, 5 and 10%), high β-galactosidase activity (2368 ± 24 Miller units), cholesterol-reducing ability (14.8 ± 4.1%), free radical scavenging activity (11.7 ± 0.7%) and hydroxyl scavenging activity (15.7 ± 0.4%). The strain had no virulence genes and was sensitive to clinically important antibiotics such as ampicillin, tetracycline and chloramphenicol. Ln. mesenteroides SJC113 produced highly viscous EPS during storage at 8 °C in skim milk with 5% sucrose. Therefore, these conditions were used for EPS production in skim milk before incorporation into fresh cheese. Four types of fresh cheese were produced: full-fat cheese (FF) made from pasteurized whole milk, non-fat cheese (NF) made from pasteurized skim milk, non-fat cheese made from skim milk fermented with Ln. mesenteroides without added sugar (NFLn0) and non-fat cheese made from skim milk fermented with Ln. mesenteroides with 5% sucrose (NFLn5). While the NF cheeses had the highest viscosity and hardness, the NFLn5 cheeses showed lower firmness and viscosity, higher water-holding capacity and lower weight loss during storage. Overall, the NFLn5 cheeses had similar rheological properties to full-fat cheeses with a low degree of syneresis. It was thus shown that the glucan-type EPS produced by Ln. mesenteroides SJC113 can successfully replace fat without altering the texture of fresh cheese.

Isolation of new plant-derived lactic acid bacteria (LAB) is highly prioritized in developing novel starter cultures for plant-based fermentation. This study explores the diversity of LAB in Danish flowers and their potential use for plant-based food fermentation. A total of 46 flower samples under 34 genera were collected for LAB isolation. By introducing an enrichment step, a total of 61 LAB strains were isolated and identified using MALDI-TOF and 16S rRNA sequencing. These strains represent 24 species across 9 genera, predominantly Leuconostoc mesenteroides, Fructobacillus fructosus, Apilactobacillus ozensis, and Apilactobacillus kunkeei. Phenotypic screening for exo-cellular polysaccharide production revealed that 40 strains exhibited sliminess or ropiness on sucrose-containing agar plates. HPLC analysis confirmed that all isolates produced exo-cellular polysaccharides containing glucose, fructose, or galactose as sugar monomers. Therefore, the strains were glucan, fructan, and galactan producers. The suitability of these strains for plant-based fermentation was characterized by using almond, oat, and soy milk. The results showed successful acidification in all three types of plant-based matrices but only observed texture development in soy by Leuconostoc, Weissella, Lactococcus, Apilactobacillus, and Fructobacillus. The findings highlight the potential of flower-derived LAB strains for texture development in soy-based dairy alternatives. [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]

A Leuconostoc mesenteroides strain (SJC113) isolated from cheese curd was found to produce large amounts of a mucoid exopolysaccharide (EPS). An analysis revealed the glucan nature of the EPS with 84.5% (1→6)-linked α-d-glucose units and 5.6% (1,3→6)-linked α-d-glucose units as branching points. The EPS showed 52% dextranase resistance and a yield of 7.4 ± 0.9 g/L from MRS medium supplemented with 10% sucrose within 48 h. Ln. mesenteroides SJC113 was also characterized and tested for the production of EPS as a fat substitute in fresh cheese. Strain SJC113 showed high tolerance to a wide range of NaCl concentrations (2, 5 and 10%), high β-galactosidase activity (2368 ± 24 Miller units), cholesterol-reducing ability (14.8 ± 4.1%), free radical scavenging activity (11.7 ± 0.7%) and hydroxyl scavenging activity (15.7 ± 0.4%). The strain had no virulence genes and was sensitive to clinically important antibiotics such as ampicillin, tetracycline and chloramphenicol. Ln. mesenteroides SJC113 produced highly viscous EPS during storage at 8 °C in skim milk with 5% sucrose. Therefore, these conditions were used for EPS production in skim milk before incorporation into fresh cheese. Four types of fresh cheese were produced: full-fat cheese (FF) made from pasteurized whole milk, non-fat cheese (NF) made from pasteurized skim milk, non-fat cheese made from skim milk fermented with Ln. mesenteroides without added sugar (NFLn0) and non-fat cheese made from skim milk fermented with Ln. mesenteroides with 5% sucrose (NFLn5). While the NF cheeses had the highest viscosity and hardness, the NFLn5 cheeses showed lower firmness and viscosity, higher water-holding capacity and lower weight loss during storage. Overall, the NFLn5 cheeses had similar rheological properties to full-fat cheeses with a low degree of syneresis. It was thus shown that the glucan-type EPS produced by Ln. mesenteroides SJC113 can successfully replace fat without altering the texture of fresh cheese. [ABSTRACT FROM AUTHOR]

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Bacteriocins produced by lactic acid bacteria are known to be useful tools for food biopreservation and fermentation control. Leuconostoc mesenteroides subsp. mesenteroides 406 and 213M0 isolated from different samples of Mongolian traditional fermented milk, airag, had been reported to produce listericidal bacteriocin-like inhibitory substances with similar but slightly different properties. In this study, the antibacterial properties and the related gene sequences of both strains were compared, and then their bacteriocins were purified and identified. Strain 406 was superior to strain 213M0 in cell growth and antibacterial activity against many strains. However, the activity of 213M0 was stronger than that of 406 against a few strains. DNA sequencing revealed two and three plasmids in 406 and 213M0, respectively, and each one of them harbored an almost identical mesentericin Y105–B105 gene cluster. Removal of these plasmids resulted in a complete loss of activity, indicating that the antibacterial activity of both strains was generated by bacteriocins encoded on the plasmids. Mesentericins Y105 and B105 were purified from both cultures, and another novel bacteriocin, named mesentericin M, was identified from the 213M0 culture only. Its structural gene was coded on a 213M0 plasmid and, surprisingly, its C-terminal three amino acid residues were post-translationally cleaved. To our knowledge, this is the first report of a C-terminal truncated bacteriocin. In conclusion, the novel bacteriocin should be mainly responsible for the difference in antibacterial properties between the two strains. [ABSTRACT FROM AUTHOR]

Copyright of Food Research & Development is the property of Food Research & Development Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Simple Summary: Mastitis is an infection of the mammary glands that affects yaks' health and milk quality. The various bacteria found in mastitis-affected yaks were examined using a technique for reading particular genetic information. We discovered that contaminated milk had higher concentrations of bacteria than healthy milk. Our findings highlight the complexity and irregularity in the milk microbiome of yaks. Understanding these bacterial communities may aid in developing more effective mastitis control measures and enhance the health and milk quality of yaks, thereby benefiting dairy producers and yak farmers. Mastitis is an inflammation of the mammary gland that can be caused by various factors, including biological, chemical, mechanical, or physical. Microbiological culture, DNA techniques, and high-throughput next-generation sequencing have been used to identify mastitis-causing pathogens in various animal species. However, little is known about microbiota and microbiome changes linked to yak milk mastitis. This study aimed to characterize the milk microbiota of healthy and mastitis-infected yaks using full-length 16S rRNA sequencing. The results showed that the bacterial microbiota comprises 7 phyla, 9 classes, 20 orders, 39 families, 59 genera, and 72 species. Proteobacteria and Firmicutes were the predominant microbial communities, with lower abundances of Bacteroidota, Actinobacteriota, Acidobacteriota, and other minor groupings also observed. Proteobacteria dominated the clinical and subclinical mastitis groups (95.36% and 89.32%, respectively), in contrast to the healthy group (60.17%). Conversely, Firmicutes were more common in the healthy group (39.7%) than in the subclinical and clinical mastitis groups (10.49% and 2.92%, respectively). The predominant organisms found in the healthy group were Leuconostoc mesenteroides, Lactococcus piscium, Carnobacterium maltaromaticum, and Lactococcus raffinolactis. Low abundances of Staphylococcus aureus species were found in both subclinical and clinical mastitis groups, with Moraxella osloensis and Psychrobacter cibarius dominating the subclinical mastitis group and Pseudomonas fluorescens dominating the clinical mastitis group. An alpha diversity study revealed that the healthy group had a higher microbial diversity than the clinical and subclinical mastitis groups. According to beta-diversity analysis, the principal coordinate analysis identified that mastitis-infected samples significantly differed from healthy ones. The milk microbiota of healthy yaks is more varied, and specific prominent taxa within various groups can act as marker microorganisms for mastitis risk. The genera Leuconostoc and Lactococcus are promising candidates for creating probiotics. [ABSTRACT FROM AUTHOR]

The Mexican oregano by-products are a source of bioactive molecules (polyphenols) that could be extracted using solid-state fermentation (SSF). This study fermented the by-products via SSF (120 h) with a lactic acid bacteria (LAB) Leuconostoc mesenteroides. Sequentially, a bioactive and chemical determination was made according to the phenolic content, antioxidant activity (DPPH●/FRAP), bioactive properties (α-amylase inhibition and antimicrobial activity against Escherichia coli), and chemical composition (HPLC-MS). The results showed that the total phenolics and flavonoid content, as well as the antioxidant activity, increased (0.60, 2.55, and 3.01 times, respectively) during the SSF process compared with unfermented material. Also, the extracts showed antimicrobial activity against E. coli and α-amylase inhibition. These inhibitory results could be attributed to bioactive compounds identified via HPLC, such as gardenin B, trachelogenin, ferulic acid, and resveratrol 3-O-glucoside. Therefore, the application of L. mesenteroides under SSF on oregano by-products comprises an eco-friendly strategy for their valorization as raw materials for the recovery of phenolic compounds that could be natural alternatives against synthetic antioxidant and antimicrobial agents, promoting a more circular and sustainable supply system within the oregano industry. [ABSTRACT FROM AUTHOR]

In the present study, selected pathogenic (Salmonella Typhimurium, Escherichia coli, Pseudomonas aeruginosa, Listeria monocytogenes, Bacillus cereus, and Staphylococcus aureus) and nonpathogenic (Pseudomonas fragi, Pseudomonas fluorescens, Brochothrix thermosphacta, Bacillus subtilis, Lactiplantibacillus plantarum, and Leuconostoc mesenteroides) bacteria were subjected in vitro in cold atmospheric pressure plasma (CAPP) treatment for up to 15 min and the changes in the surviving microbial population were determined. Plasma treatments were carried out by a plasma jet device, operating with argon (Ar) as carrier gas under constant flow (4.0 L/min) at a frequency of 1 MHz and an electrical voltage of 2–6 kV. Microbial inactivation data were modelled using linear and nonlinear (Geeraerd, Weibull) models, through which the corresponding kinetic parameters were calculated. After 15 min of exposure to plasma radiation, the total reduction in the bacterial populations was 2.12 log10 CFU mL−1 for P. fragi, 1.77 log10 CFU mL−1 for P. fluorescens, 2.30 log10 CFU mL−1 for B. thermosphacta, 1.58 log10 CFU mL−1 for B. subtilis, 1.31 log10 CFU mL−1 for L. plantarum, 3.80 log10 CFU mL−1 for L. mesenteroides (highest reduction observed), 1.12 log10 CFU mL−1 for S. Typhimurium, 1.18 log10 CFU mL−1 for E. coli, 1.43 log10 CFU mL−1 for L. monocytogenes, 1.32 log10 CFU mL−1 for B. cereus, 0.88 log10 CFU mL−1 for S. aureus, and 0.73 log10 CFU mL−1 for P. aeruginosa. The results showed a higher reduction in the population of nonpathogenic microorganisms compared to pathogens. The relatively small decrease in the inactivation of bacteria indicates that parameter optimization is necessary to be considered to improve the efficacy of the treatment. [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]

Vibrio cholerae and Vibrio parahaemolyticus are common pathogens linked to human gastroenteritis, particularly in seafood like shrimp. This study investigated the impact of lactic acid bacteria on V. cholerae and V. parahaemolyticus regarding the production of cadaverine, a concerning compound. V. cholerae NCCP 13589 and V. parahaemolyticus ATCC 27969 were significant producers of amines in experiments conducted using white-leg shrimp (Litopenaeus vannamei) and lysine decarboxylase broth. Notably, the Lactiplantibacillus plantarum NCIMB 6105 and Leuconostoc mesenteroides ATCC 10830 lactic acid bacteria strains demonstrated a pronounced antagonistic effect on the production of biogenic amines by these food-borne pathogenic bacteria. The presence of lactic acid bacteria led to a substantial reduction in cadaverine production in the lysine decarboxylase broth and shrimp extract. The co-culture of two lactobacilli species reduced the cadaverine production in V. cholerae and V. parahaemolyticus by approximately 77 and 80%, respectively. Consequently, the favorable influence of lactic acid bacteria in curbing cadaverine production by food-borne pathogens presents clear advantages for the food industry. Thus, effectively managing these pathogens could prove pivotal in controlling the biogenic amine levels in shrimp. [ABSTRACT FROM AUTHOR]

Kimoto-type Japanese rice wine (sake) has a wide variety of flavors, as the predominant microbes, including lactic acid bacteria (LAB) and nitrate-reducing bacteria, that spontaneously proliferate in the fermentation starter vary depending on the brewery. In this study, we traced the microbiota in four lots of starters manufactured in a newly established brewery and evaluated the lot-to-lot variation and characteristics of the microbiota in the brewery. The results of a 16S ribosomal RNA amplicon analysis showed that the starters brewed in the second brewing year had a more diverse microbiota than those in the first brewing year. Among the LAB predominated at the middle production stage, lactococci, including Leuconostoc spp., were detected in all the lots, while lactobacilli predominated for the first time in the second year. These results suggest that repeated brewing increased microbial diversity and altered the microbial transition pattern in the kimoto-style fermentation starters. Phylogenetic analyses for the LAB isolates from each starter identified Leuconostoc suionicum, Leuconostoc citreum, and Leuconostoc mesenteroides as predominant lactococci as well as a unique lactobacillus in place of Latilactobacillus sakei. We also found that a rice koji-derived Staphylococcus gallinarum with nitrate-reducing activity was generally predominant during the early production stage, suggesting that there was a case in which staphylococci played a role in nitrite production in the starters. These findings are expected to contribute to the understanding of the diversity of microbiota in kimoto-type sake brewing and enable control of the microbiota for consistent sake quality. [ABSTRACT FROM AUTHOR]

Obesity is caused by an energy imbalance and leads to metabolic syndrome and diseases. The gut microbiota, influenced by diet, crucially impacts obesity. Kimchi, a traditional Korean fermented food rich in lactic acid bacteria, may alter gut microbiota composition. This randomized, double-blind, placebo-controlled trial enrolled 90 participants (BMI 23–30 kg/m2) to investigate the anti-obesity effects of kimchi. Participants consumed 3000 mg of spontaneously fermented kimchi powder (S-K) or starter-fermented kimchi powder with Leuconostoc mesenteroides KCKM0828 (LMS-K) daily for 12 weeks, while the placebo group consumed lactose. Both the S-K and LMS-K groups exhibited a significant reduction in body fat mass compared to the placebo group (S-K: p = 0.004, LMS-K: p = 0.003). Kimchi consumption also increased the proportion of Akkermansia muciniphila while decreasing that of Proteobacteria. Cumulatively, these findings suggest that daily kimchi consumption may alleviate obesity symptoms by regulating gut microbiota.

In order to improve the safety and preservability of fermented vegetables, strain Leuconostoc mesenteroides AP7, with potent inhibitory effects on foodborne pathogens and bacteria causing paocai over-acidification, was selected from 8 Leuconostoc strains derived from traditional fermented vegetables in Yunnan, China. The main antimicrobial substance of AP7 was determined by eliminating the effects of organic acid and H2O2 and through protease sensitivity. The acid stability and thermal stability were analyzed and potential bacteriocin gene clusters were mined from the whole genome sequence of AP7. The results showed that the culture supernatant still had obvious antibacterial activity after excluding the influence of acid and H2O2, and after protease treatment, the antibacterial effect decreased significantly. It was speculated that the antibacterial substance in the concentrated culture supernatant was bacteriocin. The bacteriocin was sensitive to pH changes, had high thermal stability, and had a molecular weight of 6.51~14.4 kDa. Whole genome sequencing showed that the whole genome of AP7 contained 1 chromosome (1948310 bp) and 2 plasmids (37366 and 20698 bp), with a GC content of 37.7%. There was a gene cluster with Enterocin_X_chain_beta bacteriocin as the core. Its encoded product was predicted to be a positively charged hydrophilic stable protein, the secondary structure was dominated by α-helix, and the tertiary structure was mainly composed of loose peptide chains at both ends and an α-helix in the middle. In summary, the bacteriocin-producing Leuconostoc mesenteroides AP7 has excellent antibacterial properties and has the potential to be applied to the fermentation and preservation of acidic foods.

In order to explore the effects of co-fermentation of Leuconostoc mesenteroides L5 and Kazachstania exigua M1 on the physicochemical properties of low-salt and low-acid fermented mustard during fermentation process and storage period, the co-fermentation group was compared with a natural fermentation group and a fermentation group solely with the lactic acid bacterium L5. The pH, total acid, total ester and nitrite content etc. during the fermentation process and storage period were measured. The texture and color difference of fermented mature paocai and accelerated preserved paocai were analyzed alongside sensory evaluation. The results showed that L5 and M1 co-fermented paocai contained nitrite as lowest as 1.45 mg/kg , and total acid (2.46 g/kg) was significantly lower than that of the other two groups (P

[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]

In order to study the effects of different lactic acid bacteria on the quality of pickled radish, pickled radish was prepared with Leuconostoc mesenteroides AP7, Lactiplantibacillus pentosus LP10 and AP7-LP10 combination. The changes in physicochemical indicators, color differences, texture properties and sensory indicators during the fermentation process were analyzed. The results showed that the decrease rate of pH and reducing sugar content and the increase rate of total acid and lactic acid in the inoculated group were better than those in the natural fermentation group (P<0.05). For the inoculated group, the nitrite content was low, and no nitrite peak appeared. The pectinase activity remained at a low level. For the AP7-LP10 and AP7 groups, the L* was higher than that of the other two groups (P<0.05), and the browning index and polyphenol oxidase activity remained at a low level. After 7 days of fermentation, the hardness of AP7-LP10 group (70.92±3.94 N) was higher than that of other groups (P<0.05). The sensory score of AP7-LP10 was the highest (92±2.11). In summary, the pickled radish inoculated with lactic acid bacteria is fast to mature and safe. The combination of AP7-LP10 can improve the quality of pickled radish. [ABSTRACT FROM AUTHOR]

In order to improve the safety and preservability of fermented vegetables, strain Leuconostoc mesenteroides AP7, with potent inhibitory effects on foodborne pathogens and bacteria causing paocai over-acidification, was selected from 8 Leuconostoc strains derived from traditional fermented vegetables in Yunnan, China. The main antimicrobial substance of AP7 was determined by eliminating the effects of organic acid and H2O2 and through protease sensitivity. The acid stability and thermal stability were analyzed and potential bacteriocin gene clusters were mined from the whole genome sequence of AP7. The results showed that the culture supernatant still had obvious antibacterial activity after excluding the influence of acid and H2O2, and after protease treatment, the antibacterial effect decreased significantly. It was speculated that the antibacterial substance in the concentrated culture supernatant was bacteriocin. The bacteriocin was sensitive to pH changes, had high thermal stability, and had a molecular weight of 6.51~14.4 kDa. Whole genome sequencing showed that the whole genome of AP7 contained 1 chromosome (1948310 bp) and 2 plasmids (37366 and 20698 bp), with a GC content of 37.7%. There was a gene cluster with Enterocin_X_chain_beta bacteriocin as the core. Its encoded product was predicted to be a positively charged hydrophilic stable protein, the secondary structure was dominated by a-helix, and the tertiary structure was mainly composed of loose peptide chains at both ends and an α-helix in the middle. In summary, the bacteriocin-producing Leuconostoc mesenteroides AP7 has excellent antibacterial properties and has the potential to be applied to the fermentation and preservation of acidic foods. [ABSTRACT FROM AUTHOR]

The anti-inflammatory effects of supernatants produced from sprouted barley inoculated with Lactiplantibacillus plantarum KCTC3104 (Lp), Leuconostoc mesenteroides KCTC3530 (Lm), Latilactobacillus curvatus KCTC3767 (Lc), or a mixture of these lactic acid bacteria were investigated using RAW264.7 macrophages. BLp and BLc, the lyophilized supernatants of fermented sprouted barley inoculated with Lp and Lc, respectively, effectively reduced the nitric oxide (NO) levels hypersecreted by lipopolysaccharide (LPS)-stimulated RAW264.7 and LPS-stimulated Caco-2 cells. BLp and BLc effectively reduced the NO levels in LPS-stimulated RAW264.7 macrophages, and these effects tended to be concentration-dependent. BLc and BLp also exhibited strong DPPH radical scavenging activity and immunostimulatory effects. BLp and BLc significantly suppressed the levels of NO and pro-inflammatory cytokines such as TNF-α, IL-1β, and IL-6 in LPS-stimulated RAW264.7 macrophages and LPS-stimulated Caco-2 cells, indicating their anti-inflammatory effects. These effects were greater than those of unfermented barley sprout (Bs). The functional components of Bs, BLp, and BLc were analyzed by HPLC, and it was found that lutonarin and saponarin were significantly increased in the fermented sprouted barley sample inoculated with Lp and Lc (BLp and BLc). [ABSTRACT FROM AUTHOR]

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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]

Accumulated evidence has supported the probiotic activity of Leuconostoc mesenteroides (L. mesenteroides) which can yield beneficial metabolites via fermentation. Here, bovine milk rich in phenylalanine（PHE) was used as a source for fermentation of L. mesenteroides. The complexes of PHE with bacterial phenylalanine hydroxylase (PheH) at two temperatures were revealed via molecular dynamics simulation. Two carbon hydrogen bonds and a Pi-Alkyl T-shaped interaction were newly formed at an active site of the PheH-PHE complex. The PheH interacted with two different hydrogen atoms in an amine of PHE via conventional hydrogen bonds at 37 °C, a temperature that accelerated the milk fermentation of L. mesenteroides. Twenty-eight metabolites including various neurotransmitters in fermented milk were identified and quantified by liquid chromatography coupled to quadrupole ion trap (Q-Trap) tandem mass spectrometry. Ex ovo injection of milk ferments into the yolk sac of chicken embryos enhanced a rising temperature-induced increase in heartbeats towards the normal resting level. The neurotransmitter-rich milk ferments hold potential for using to adjust energy metabolism, referred from heart rates, during fluctuating temperature conditions.

Previously, microbial communities of five commercial kimchi added with seafood and one kimchi without seafood were analyzed using a culture-independent (CI) method. In the current study, microbial communities of the same samples were analyzed using a culture-dependent (CD) method with two media: tryptic soy agar (TSA) and Lactobacilli de Man, Rogosa and Sharpe (MRS) agar. MRS agar showed a higher proportion of lactic acid bacteria, while TSA showed a higher proportion of Bacillus species. Leuconostoc mesenteroides became dominant over time except in kimchi added with hongeu (HBK, okamejei kenojei). In the case of HBK, Bacillus was dominant. The low pH of HBK was confirmed by cell size and heat treatment under pH 4–7 conditions that Bacillus could be present in the form of spores. With the CD method, only Lactococcus lactis, Leu. citreum, and Weissella cibaria were detected. With the CI method, only Pediococcus inopinatus was detected. A notable finding was that Leu. mesenteroides was more abundant than Latilactobacillus sakei with the CD method, whereas it was similar or lower with the CI method. This discrepancy was confirmed to be due to different rates of DNA recovered from the two strains. This shows that the assay method may influence the detection of these two strains.

The spatiotemporal distributions of microbes in soil by different methods could affect the efficacy of the microbes to reduce the soil hydraulic conductivity. In this study, the specimens of bio-mediated sands were prepared using three different methods, i.e. injecting, mixing, and pouring a given microbial solution onto compacted sand specimens. The hydraulic conductivity was measured by constant-head tests, while any soil microstructural changes due to addition of the microbes were observed by scanning electron microscope (SEM) and mercury intrusion porosimetry (MIP) tests. The amount of dextran concentration produced by microbes in each type of specimen was quantified by a refractometer. Results show that dextran production increased exponentially after 5–7 d of microbial settling with the supply of culture medium. The injection and mixing methods resulted in a similar amount and uniform distribution of dextran in the specimens. The pouring method, however, produced a nonuniform distribution, with a higher concentration near the specimen surface. As the supply of culture medium discontinued, the dextran content near the surface produced by the pouring method decreased dramatically due to high competition for nutrients with foreign colonies. Average dextran concentration was negatively and correlated with hydraulic conductivity of bio-mediated soils exponentially, due to the clogging of large soil pores by dextran. The hydraulic conductivity of the injection and mixing cases did not change significantly when the supply of culture medium was absent.

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]

From traditional Gifu ayu-narezushi, Leuconostoc, Latilactobacillus, and Enterococcus were isolated as dominant genera. Isolated strains of Leuconostoc mesenteroides showed high growth inhibition activity against Staphylococcus aureus and Escherichia coli. The isolated strain, Enterococcus lactis EC52, could produce 1-aminobutyric acid (GABA). These results indicated that Enterococcus lactis and Leuconostoc mesenteroides were lactic acid bacteria, which have GABA-producing and antimicrobial activities, respectively, in traditional Gifu ayu-narezushi. [ABSTRACT FROM AUTHOR]

This study aimed to isolate lactic acid bacteria (LAB) from a traditional Ethiopian fermented product, Tella, and evaluate their functional properties. Of forty-three isolates, seven LAB were screened and identified as Pediococcus pentosaceus, Latilactobacillus curvatus, Leuconostoc mesenteroides, and Lactiplantibacillus plantarum species. The isolates were tested for their alcohol tolerance, acid and bile resistance, auto-aggregation, co-aggregation, hydrophobicity, antibacterial activity, and antibiotic susceptibility. LAB isolates, specifically P. pentosaceus TAA01, L. mesenteroides TDB22, and L. plantarum TDM41, showed a higher degree of alcohol tolerance in 8% and 10% (w/v) ethanol concentrations. Additionally, these three isolates displayed survival rates >85% in both acidic pH and bile environments. Among the isolates, L. plantarum TDM41 demonstrated the highest auto-aggregation, co-aggregation, and hydrophobicity with (44.9 ± 1.7)%, (41.4 ± 0.2)%, and (52.1 ± 0.1)% values, respectively. The cell-free supernatant of the isolates exhibited antibacterial activity against foodborne pathogens of Escherichia coli, Salmonella Enteritidis, and Staphylococcus aureus. Each isolate exhibited various levels of resistance and susceptibility to seven antibiotics and resistance was observed against four of the antibiotics tested. After performing a principal component analysis, Pediococcus pentosaceus TAA01, L. mesenteroides TDB22, and L. plantarum TDM41 were selected as the most promising ethanol-tolerant probiotic isolates. [ABSTRACT FROM AUTHOR]