Probiotic characterization of Lactobacillus brevis KU15153 showing antimicrobial and antioxidant effect isolated from kimchi

Whole Genome Mining and Characterization of a New Probiotic Strain Levilactobacillus brevis ILSH3 from Handia: An Ethnic Fermented Beverage of Odisha, India

Isolation and characterization of probiotics from traditional fermented food have contributed many beneficial strains to the field of health and nutritional sciences. Handia, a traditional fermented alcoholic beverage popular in different parts of Odisha, was our source of isolation. This study characterizes one such potential bacteria, Levilactobacillus brevis ILSH3 (H3) isolated from Handia. The investigation for the probiotic attributes as per ICMR-DBT guidelines qualified the checkpoint assays like acid and bile tolerance, bile salt hydrolase activity, antimicrobial properties, and pathogen exclusion ability. The whole genome sequence of H3 (2,460,966 bp in size with GC content of 45.62%) was subjected to comparative genome analysis for its taxonomic identification and validation of probiotic potential. Various genes pertaining to its probiotic potential were identified in the genome and it showed zero matches against any pathogenic families. Metabolite profiling of cell-free supernatant using liquid chromatography-mass spectrometry revealed the presence of essential amino acids, short-chain fatty acids, antimicrobial molecules, immunomodulatory molecules, and flavor/aroma-enhancing compounds. Immunomodulatory property investigation using Bioplex and qRT-PCR showed a reduction in the levels of pro-inflammatory cytokines in L. brevis ILSH3-treated Caco-2 cells. Collectively, the results demonstrate that this Handia-origin bacteria Levilactobacillus brevis ILSH3 possesses desirable attributes of a probiotic, which is now open for nutritional and health biologists to explore. This new probiotic strain may show promising results when utilized in healthcare or functional foods.

Anti-adipogenic effect of Latilactobacillus curvatus CK17 isolated from kimchi and its potential probiotic properties

Probiotics and their cellular constituents are pivotal in modulating lipid metabolism in adipocytes, potentially offering novel approaches to obesity prevention. This study investigates the probiotic characteristics and anti-adipogenic effects of lactic acid bacteria (LAB) strains isolated from kimchi. Twenty LAB strains, identified as Latilactobacillus sakei, Latilactobacillus curvatus, and Leuconostoc mesenteroides, were evaluated for lipase inhibitory activity. Among them, L. sakei CKC1 and L. curvatus CK17 exhibited the strongest inhibition and were selected for further study. Notably, L. curvatus CK17 significantly reduced lipid accumulation in 3T3-L1 adipocytes and downregulated key adipogenic markers, including PPARγ, C/EBPα, aP2, SREBP1c, ACC, and FAS (p < 0.05). Additionally, CK17 survived simulated digestive conditions, adhered effectively to Caco-2 cells, and exhibited antibacterial activity. These findings suggest that L. curvatus CK17 as a promising probiotic candidate for obesity prevention, with potent anti-adipogenic properties.

Heat-killed Lactiplantibacillus plantarum WB3813 and Lactiplantibacillus plantarum WB3814 Alleviate LPS-Induced Inflammatory Damage and Apoptosis in A549 Cells

Chronic obstructive pulmonary disease (COPD) is characterized by chronic lung inflammation and apoptosis. Although paraprobiotics are known for their beneficial effects on respiratory health, research on their effect on COPD is limited. In this study, we investigated the effects of heat-killed Lactiplantibacillus plantarum WB3813 and Lact. plantarum WB3814 on inflammation and apoptosis in lipopolysaccharide (LPS)-induced A549 cells. Both strains demonstrated appropriate probiotic properties and were confirmed to be safe. The results showed that heat-killed lactic acid bacteria (H-LAB) exhibited anti-inflammatory and anti-apoptotic effects. Although LPS exposure reduced cell viability, treatment with the two H-LAB demonstrated a protective effect on the cells. RT-PCR results showed that H-LAB pretreatment reduced COPD-related mRNA expression levels, and western blotting analysis indicated downregulation of the activation NF-κB and intrinsic apoptotic signaling pathways. Additionally, elevated levels of IL-6 and eotaxin induced by LPS decreased. Furthermore, the strains significantly lowered intracellular ROS levels, which were increased by LPS, and promoted radical-scavenging activity. Although the in vivo effects have not yet been elucidated, this study demonstrated that heat-killed or live Lact. plantarum WB3813 and Lact. plantarum WB3814 exhibit anti-inflammatory and anti-apoptotic effects in a lung epithelial cell injury model. These findings provide experimental evidence for the development of functional foods to improve bronchial health and for potential clinical applications in COPD treatment.

Determination of bacteriocin genes and antimicrobial activity of Lactiplantibacillus plantarum isolated from feta cheese samples

In this study designed to isolate lactic acid bacteria (LAB) with bacteriocin production potential, white cheese samples were collected from different provinces of Turkey and isolation was carried out. A series of experiments were carried out for the main purpose and the actual bacteriocin producers were identified by detecting the genes encoding this bacteriocin. The experiments carried out in this direction were initially carried out with 20 isolates and as a result of various experiments, the number of isolates was reduced to 8 and the study was continued with 8 isolates. In order to determine that the eight isolates identified as a result of a phenotypic and biochemical characterization study were true bacteriocin-producing strains, their antibacterial activity was investigated and then the presence of bacteriocin genes was examined by specific polymerase chain reaction (PCR) using gene-specific primers. As a result, MS16 coded Lactiplantibacillus plantarum OR922652 was found to have strong antibacterial activity against Escherichia coli, Klebsiella pneumonia, Yersinia enterocolitica, Listeria monocytogenes, Bacillus cereus, and Staphylococcus aureus; the isolate was susceptible to clinically important antibiotics (ciprofloxacin, gentamicin, penicillin G, ampicillin, chloramphenicol, and vancomycin) and resistant to erythromycin, had no hemolytic activity and possessed plnA and plnD genes encoding bacteriocin production. In conclusion, the MS16 coded L. plantarum isolate has emerged as a promising strain that can be used especially in the health field and in the food industry related to LAB.

Plant-based probiotic foods: current state and future trends

Abstract

Plant-based probiotic foods (PBPFs) have recently become a notable choice for many consumers. While less recognized than dairy products, these foods offer efficient alternatives for individuals with lactose intolerance, vegans, or those aiming for more sustainable dietary practices. Traditional fermented PBPFs, such as kimchi, sauerkraut, and kombucha, are part of cultures from different countries and have gained more significant popularity in recent years globally due to their peculiar flavors and health benefits. However, new plant-based probiotic products have also been studied and made available to consumers of the growing demand in this sector. Therefore, this review discusses trends in plant-based probiotic production, known benefits, and characteristics. Challenges currently faced in manufacturing, distribution, marketing, consumer acceptance, and legislation are also discussed.

Graphical abstract

Development and validation of a PMA-qPCR method for accurate quantification of viable Lacticaseibacillus paracasei in probiotics

The effectiveness of probiotic products hinges on the viability and precise quantification of probiotic strains. This study addresses this crucial requirement by developing and validating a precise propidium monoazide combination with quantitative polymerase chain reaction (PMA-qPCR) method for quantifying viable Lacticaseibacillus paracasei in probiotic formulations. Initially, species-specific primers were meticulously designed based on core genes from the whole-genome sequence (WGS) of L. paracasei, and they underwent rigorous validation against 462 WGSs, 25 target strains, and 37 non-target strains across various taxonomic levels, ensuring extensive inclusivity and exclusivity. Subsequently, optimal PMA treatment conditions were established using 25 different L. paracasei strains to effectively inhibit dead cell DNA amplification while preserving viable cells. The developed method exhibited a robust linear relationship (R 2 = 0.994) between cycle threshold (Cq) values and viable cell numbers ranging from 103 to 108 CFU/mL, with an impressive amplification efficiency of 104.48% and a quantification limit of 7.30 × 103 CFU/mL. Accuracy assessments revealed biases within ±0.5 Log10 units, while Bland-Altman analysis demonstrated a mean bias of 0.058 Log10, with 95% confidence limits of -0.366 to 0.482 Log10. Furthermore, statistical analysis (p = 0.76) indicated no significant differences between theoretical and measured values. This validated PMA-qPCR method serves as a robust and accurate tool for quantifying viable L. paracasei in various sample matrices, including pure cultures, probiotics as food ingredients, and composite probiotic products, thereby enhancing probiotic product quality assurance and contributing to consumer safety and regulatory compliance.

In vitro assessment of probiotic properties of lactic acid bacteria isolated from camel milk: enhancing sustainable foods

Probiotic properties of isolated lactic acid bacteria (LAB) from sustainable foods including camel milk are the potential research domains. For this purpose, camel milk samples (n = 20), from four different herds of Camelus dromedarius, were processed for the identification of LAB strains based on biochemical profiles followed by amplification and sequence analysis of the 16S rRNA gene. The probiotic characteristics, i.e., acids and bile salts tolerance, antimicrobial susceptibility profiles, hemolytic and antimicrobial activities, auto-aggregation assay, and adhesion to HT-29 epithelial cells were determined. Thirteen out of 20 milk samples were initially found positive for the growth of probiotics or LAB which were further confirmed as Lacticaseibacillus casei (5) and Pediococcus pentosaceus (3). The probiotics/LAB strains showed maximum survival (%) = 92.06 ± 1.82 and 81.35 ± 3.64 against acids and bile salts, respectively. The LAB strains were found sensitive to amoxicillin, ceftazidime, imipenem, linezolid, ofloxacin, tetracycline, tobramycin, and vancomycin. None of the LAB strains showed hemolytic activity. L. casei-04 strain showed a maximum zone of inhibition (15.33 ± 0.58) against multidrug-resistant E. coli AZ1 strain whereas, L. casei-05 showed a maximum zone of inhibition (16.33 ± 1.15) against methicillin-resistant S. aureus Saba-1 strain. L. casei-03 showed maximum percentage auto-aggregation (28.65 ± 1.96) at 4 h while L. casei-01 showed (41.10 ± 3.03) at 24 h of incubation. Maximum adhesion was shown by P. pentosaceus-01 (11.14%) followed by L. casei-02 (9.73%). Altogether, the current findings suggested that camel milk has significant potential of providing probiotics/LAB strains into human food chain and enabling camel milk as potential sustainable food.

Impact of a Fruit-Vegetable Preparation Fortified with Potato Starch Resistant Dextrin on Selected Health Indicators in Overweight Children

Developing modified dietary fibers that maintain prebiotic benefits without significantly affecting meal taste is of high importance in the midst of the obesity pandemic. These benefits include regulating the composition of gut microbiota, increasing feelings of fullness, and improving human metabolic parameters. This study investigated the use of a resistant dextrin (RD) derived from potato starch, which possesses prebiotic properties, as a potential additive in vegetable-fruit preparations that aid weight loss and improve health markers in overweight children. HPLC was employed to examine metabolites like lactic acid, short-chain fatty acids (SCFAs; formic, acetic, propionic, butyric, and valeric acids), and branched-chain fatty acids (BCFAs; isobutyric and isovaleric acids). The activities of α-glucosidase, β-glucosidase, α-galactosidase, β-galactosidase, and β-glucuronidase enzymes in fecal samples were measured using spectrophotometric analysis at a wavelength of 400 nm. Incorporating the RD into vegetable-fruit preparations yielded favorable outcomes in terms of increased concentrations of the tested metabolites (SCFAs and BCFAs) and enhanced fecal enzyme activities after 6 months of consuming the preparations. Furthermore, these effects were found to last for an extended period of 3 months even after discontinuing the treatment. The study has shown that including RD into vegetable-fruit preparations enhances the metabolic parameters of obese and overweight children, hence providing a strong rationale for the widespread usage of these preparations in the industry.

Characterization and Assessment of Native Lactic Acid Bacteria from Broiler Intestines for Potential Probiotic Properties

Probiotics are the most promising alternative to antibiotics for improving animal production and controlling pathogenic infections, while strains derived from natural hosts are considered highly desirable due to their good adaptation to the gastrointestinal tract. The aim of this study was to screen Lactobacillus with broad-spectrum antibacterial activity from broilers fed an antibiotic-free diet and evaluate their potential as poultry probiotics. A total of 44 lactic acid bacteria (LAB) strains were isolated from the intestines of healthy broilers, among which 3 strains exhibited outstanding antimicrobial activity and were subsequently identified through 16S rRNA sequencing as Enterococcus faecium L8, Lactiplantibacillus plantarum L10, and Limosilactobacillus reuteri H11. These three isolates demonstrated potent bacteriostatic activity against Staphylococcus aureus, Listeria monocytogenes, Escherichia coli, and Salmonella cholerae, with inhibition zones ranging from 15.67 ± 1.53 to 21.33 ± 0.58 mm. The selected LAB strains exhibited high tolerance to acid and bile salts, with L. reuteri H11 displaying the highest survival rate (ranging from 34.68% to 110.28%) after exposure to 0.3% (w/v) bile salts for 6 h or a low pH environment (pH 2, 2.5, and 3) for 3 h. Notably, L. reuteri H11 outperformed other strains in terms of hydrophobicity (84.31%), auto-aggregation (53.12%), and co-aggregation with E. coli ATCC 25922 (36.81%) and S. aureus ATCC 6538 (40.20%). In addition, the three LAB isolates were either fully or moderately susceptible to the tested antibiotics, except for strain L8, which resisted gentamycin and vancomycin. Consequently, these three LAB strains, especially L. reuteri H11, isolated from the intestines of broiler chickens, represent promising probiotic candidates that can be employed as feed additives to enhance production performance and control poultry pathogens.

Probiotic Lactobacillus plantarum Ln4 Showing Antimicrobial and Antibiofilm Effect against Streptococcus mutans KCTC 5124 Causing Dental Caries

Dental caries has known as an infectious disease that is considered a serious global public health problem. Recently, report indicate that probiotics play a vital role in maintaining oral health. Therefore, this study aimed to evaluate the prevention effects of Lactobacillus plantarum Ln4 against dental infection by the pathogenic bacterium Streptococcus mutans KCTC 5124 through biofilm formation inhibition. To evaluate such prevention effects against S. mutans KCTC 5124, antimicrobial activity, auto-aggregation, co-aggregation, cell surface hydrophobicity, total exopolysaccharide (EPS) production rate, and biofilm formation were analyzed. Results showed that L. plantarum Ln4 showed higher antimicrobial activity than L. rhamnosus GG (LGG). In the group treated with L. plantarum Ln4, the co-aggregation (58.85%), cell surface hydrophobicity (16.75%), and EPS production rate (73.29%) values were lower than those of LGG and the negative control. Additionally, crystal violet staining and confocal laser scanning microscopy (CLSM) revealed that L. plantarum Ln4 effectively inhibited biofilm formation in S. mutans KCTC 5124. Therefore, L. plantarum Ln4 could be used in the industry as a probiotics to prevent and improve oral health.

Isolation of a Potential Probiotic Levilactobacillus brevis and Evaluation of Its Exopolysaccharide for Antioxidant and α-Glucosidase Inhibitory Activities

The probiotic properties of ten lactic acid bacteria and antioxidant and α-glucosidase inhibitory activities of the exopolysaccharide (EPS) of the selected strain were investigated in this study. Levilactobacillus brevis L010 was one of the most active strains across all the in vitro tests. The cell-free supernatant (50 g/l) of L. brevis L010 showed high levels of both α-glucosidase inhibitory activity (98.73 ± 1.32%) and 2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging activity (32.29 ± 3.86%). The EPS isolated from cell-free supernatant of L. brevis L010 showed 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) radical-scavenging activity (80.27 ± 2.51%) at 80 g/l, DPPH radical-scavenging activity (38.19 ± 9.61%) at 40 g/l, and ferric reducing antioxidant power (17.35 ± 0.20 mg/l) at 80 g/l. Further, EPS exhibited inhibitory activities against α-glucosidase at different substrate concentrations. Kinetic analysis suggests that the mode of inhibition was competitive, with a kinetic constant of Km = 2.87 ± 0.88 mM and Vmax = 0.39 ± 0.06 μmole/min. It was concluded that the EPS might be one of the plausible candidates for possible antioxidant and α-glucosidase activities of the L. brevis L010 strain.

Assessing the Probiotic Effects of Pediococcus pentosaceus CACC616 in Weaned Piglets

During weaning, piglets experience various stressor events that disrupt their gut microbiota and immune balance, decrease growth parameters, and increase mortality rates. In this study, we assessed the efficacy of Pediococcus pentosaceus CACC616 as a probiotic supplement. We characterized this strain and evaluated its effect on improving growth performance, modulating gut microbiota composition, and reducing noxious odor components in weaned piglets compared to a non-supplementary diet (control). During the 26-day period, 40 crossbred weaned piglets were randomly assigned to pens with 20 animals each in two groups: control and treatment groups with CACC616. On day 26, the treatment group exhibited a lower feed conversion ratio (FCR) and a significant alteration in gut microbial composition, correlating with improved growth parameters and gut health (p < 0.05). The treatment group also exhibited significantly reduced digestibility- and intestinal-environment-related noxious odor components (p < 0.05). The CACC616 strain effectively reduced pathogenic genera numbers, including Campylobacter, Mogibacterium, Escherichia-Shigella, and Desulfovibrio spp., with the treatment group exhibiting lower fecal calprotectin levels than the control group (p < 0.05). Overall, this study revealed that the functional probiotic CACC616 contributes to enhanced FCR and effectively modulates weaned piglets' inflammation and intestinal microbiota.

Harnessing the potential of probiotics in the treatment of alcoholic liver disorders

In the current scenario, prolonged consumption of alcohol across the globe is upsurging an appreciable number of patients with the risk of alcohol-associated liver diseases. According to the recent report, the gut-liver axis is crucial in the progression of alcohol-induced liver diseases, including steatosis, steatohepatitis, fibrosis, cirrhosis, and hepatocellular carcinoma. Despite several factors associated with alcoholic liver diseases, the complexity of the gut microflora and its great interaction with the liver have become a fascinating area for researchers due to the high exposure of the liver to free radicals, bacterial endotoxins, lipopolysaccharides, inflammatory markers, etc. Undoubtedly, alcohol-induced gut microbiota imbalance stimulates dysbiosis, disrupts the intestinal barrier function, and trigger immune as well as inflammatory responses which further aggravate hepatic injury. Since currently available drugs to mitigate liver disorders have significant side effects, hence, probiotics have been widely researched to alleviate alcohol-associated liver diseases and to improve liver health. A broad range of probiotic bacteria like Lactobacillus, Bifidobacteria, Escherichia coli, Sacchromyces, and Lactococcus are used to reduce or halt the progression of alcohol-associated liver diseases. Several underlying mechanisms, including alteration of the gut microbiome, modulation of intestinal barrier function and immune response, reduction in the level of endotoxins, and bacterial translocation, have been implicated through which probiotics can effectively suppress the occurrence of alcohol-induced liver disorders. This review addresses the therapeutic applications of probiotics in the treatment of alcohol-associated liver diseases. Novel insights into the mechanisms by which probiotics prevent alcohol-associated liver diseases have also been elaborated.

Assessing the protection mechanisms against Enterobacter aerogenes by analyzing aggregation, adherence, antagonistic activity, and safety properties of potentially probiotic strain Lactobacillus brevis G145

The aim of this study was to evaluate the probiotic potential of Lactobacillus brevis G145 isolated from traditional Khiki cheese, analyzing pH and bile resistance, physicochemical properties of the strain (hydrophobicity, auto- and co-aggregation), cholesterol removal, hydroxyl radical scavenging activity, adhesion ability to Caco-2 cells monolayer, and adhesion competition on Enterobacter aerogenes (competition, inhibition and replacement assays). Also, DNase, haemolytic activity, biogenic amine production and antibiotic susceptibility was investigated. L. brevis G145 was resistant to acidic pHs, bile salts, and simulated gastrointestinal conditions, and showed remarkable cell surface hydrophobicity (49.56%), co-aggregation (28.90%), auto-aggregation (34.10%), adhesion (9.40%), cholesterol removal (45.50%), and antioxidant (52.19%) properties. According to the results of well diffusion agar and disc diffusion agar tests, the highest and lowest inhibition zones were accounted for Staphylococcus aureus and Enterobacter aerogenes, respectively. The isolate did not show haemolytic, DNAse, and biogenic amine production properties. It was sensitive to antibiotics erythromycin, ciprofloxacin, and chloramphenicol, and semi-sensitive to imipenem, ampicillin, nalidixic acid, and nitrofurantoin. According to the findings of probiotic tests L. brevis G145 can be used as a in the food industry.

Probiotic Weissella cibaria displays antibacterial and anti-biofilm effect against cavity-causing Streptococcus mutans

Streptococcus mutans is a significant contributor to dental caries and causes functional and aesthetic discomfort. Weissella cibaria strains were isolated from kimchi, and their functional properties were determined. In this study, the antibacterial and antibiofilm effects of four W. cibaria strains (D29, D30, D31, and B22) were evaluated against three S. mutans strains using culture fluid and cell-free supernatants. The results showed that W. cibaria reduced the exopolysaccharides production and auto-aggregation, increased co-aggregation, and downregulated virulence factors, leading to the inhibition of bacterial growth and biofilm formation. These findings were confirmed using scanning electron microscopy and confocal laser scanning microscopy. These results indicate that oral health can be potentially improved by W. cibaria.

ESKAPEE Pathogen Biofilm Control on Surfaces with Probiotic Lactobacillaceae and Bacillus species

Combatting the rapidly growing threat of antimicrobial resistance and reducing prevalence and transmission of ESKAPEE pathogens in healthcare settings requires innovative strategies, one of which is displacing these pathogens using beneficial microorganisms. Our review comprehensively examines the evidence of probiotic bacteria displacing ESKAPEE pathogens, with a focus on inanimate surfaces. A systematic search was conducted using the PubMed and Web of Science databases on 21 December 2021, and 143 studies were identified examining the effects of Lactobacillaceae and Bacillus spp. cells and products on the growth, colonization, and survival of ESKAPEE pathogens. While the diversity of study methods limits evidence analysis, results presented by narrative synthesis demonstrate that several species have the potential as cells or their products or supernatants to displace nosocomial infection-causing organisms in a variety of in vitro and in vivo settings. Our review aims to aid the development of new promising approaches to control pathogen biofilms in medical settings by informing researchers and policymakers about the potential of probiotics to combat nosocomial infections. More targeted studies are needed to assess safety and efficacy of different probiotic formulations, followed by large-scale studies to assess utility in infection control and medical practice.

Immunostimulatory activity of Lactococcus lactis LM1185 isolated from Hydrangea macrophylla

The lactic acid bacteria, Lactococcus lactis subsp. lactis LM1185 was isolated from Hydrangea macrophylla. Strain LM1185 showed 50.5% of acid tolerance at pH 2.5 for 2 h and 30.4% of 0.3% (w/v) bile salt tolerance for 24 h. The antioxidant activity of this strain was measured at 99.4% of 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging activity. When RAW 264.7 macrophage cells were treated with strain LM1185, there was no observed cytotoxicity. This strain showed high nitric oxide production and mRNA expression levels of cytokines such as tumor necrosis factor-α and inducible nitric oxide synthase (iNOS). The nuclear factor-kB signaling pathway was activated by this strain resulting in the production of iNOS and cyclooxygenase-2 determined by western blotting. The present results indicated that L. lactis subsp. lactis LM1185 could be used as potential probiotics and may play a crucial role in the immunostimulatory effect on macrophages.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-022-01199-5.

Probiotic and antioxidant properties of C30 carotenoid-producing Lactiplantibacillus plantarum isolated from kimchi

This study focuses on the development of functional probiotics using caroteonid-producing lactic acid bacteria (LAB) with antioxidant properties. Thirty LAB strains were evaluated for their probiotic properties. Carotenoid biosynthesis gene cluster (crtMN operon) was detected using polymer chain reaction (PCR). The carotenoid identified as 4,4'-diaponeurosporene was analyzed via UV visible absorption spectra and HPLC. Five carotenoid-producing strains showed antioxidant activities. Lactiplantibacillus plantarum MGB0112, which showed the highest carotenoid production measuring at 470 nm of absorbance per ml of culture broth (0.014 A470nm/ml), showed low pH (56.5%) and bile salt (97.8%) tolerance with high adhesion properties (55.1% for toluene). Furthermore, this strain and 4,4'-diaponeurosporene extract exhibited antioxidant activity (99.5 and 40.1%, respectively) against DPPH free radicals in vitro. Their antioxidant properties were confirmed in vivo (45.6 and 55.2% survival rates in Caenorhabditis elegans). Therefore, C30 carotenoid-producing strain MGB0112 demonstrates outstanding antioxidant effects and can be a potential functional probiotics.

Potential Probiotic Lactic Acid Bacteria with Anti-Penicillium expansum Activity from Different Species of Tunisian Edible Snails

This study aimed to isolate lactic acid bacteria (LAB) from the digestive tract, meat and slime of edible snails (Helix lucorum, Helix aspersa and Eobania vermiculata) and investigate their antagonistic activity against Penicillium expansum. They were then characterized for their probiotic potential. Among 900 bacterial isolates, 47 LAB exhibiting anti-P. expansum activity were identified through matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) as Levilactobacillus brevis (25), Lactococcus lactis (3), Enterococcus faecium (12), Enterococcus faecalis (4), Enterococcus casseliflavus (1), and Enterococcus mundtii (2). Sixty-two percent of the strains were tolerant to 100 mg/L of lysozyme. Seventy two percent of the isolates were able to survive at pH 3 and most of them tolerate 2.5% bile salt concentration. Moreover, 23% of the strains displayed bile salt hydrolase activity. Interestingly, all strains were biofilm strong producers. However, their auto- and co-aggregation properties were time and pH dependent with high aggregative potentiality at pH 4.5 after 24 h. Remarkably, 48.94% of the strains showed high affinity to chloroform. The safety assessment revealed that the 47 LAB had no hemolytic activity and 64% of them lacked mucin degradation activity. All isolated strains were susceptible to gentamycin, streptomycin, tetracycline, chloramphenicol, and trimethoprim-sulfamethoxazole. Overall, 43 LAB strains showed inhibitory activity against a broad spectrum of pathogenic Gram-positive and gram-negative bacteria, fungi, and yeast. Our findings suggest that L. brevis (EVM12 and EVM14) and Ent. faecium HAS34 strains could be potential candidates for probiotics with interesting antibacterial and anti-P. expansum activities.

Does kimchi deserve the status of a probiotic food?

Kimchi is a traditional fermented vegetable side dish in Korea and has become a global health food. Kimchi undergoes spontaneous fermentation, mainly by lactic acid bacteria (LAB) originating from its raw ingredients. Numerous LAB, including the genera Leuconostoc, Weissella, and Lactobacillus, participate in kimchi fermentation, reaching approximately 9-10 log colony forming units per gram or milliliter of food. The several health benefits of LAB (e.g., antioxidant and anti-inflammatory properties) combined with their probiotic potential in complex diseases including obesity, cancer, atopic dermatitis, and immunomodulatory effect have generated an interest in the health effects of LAB present in kimchi. In order to estimate the potential of kimchi as a probiotic food, we comprehensively surveyed the health functionalities of kimchi and kimchi LAB, and their effects on human gut environment, highlighting the probiotics function.

Characterization of Probiotic Properties of Lacticaseibacillus paracasei L2 Isolated from a Traditional Fermented Food "Lben"

Lben is a dairy fermented food that is largely consumed in Tunisia for its numerous health benefits that are related to the existence of probiotics. Lactic Acid Bacteria (LAB) are well known for their beneficial probiotic properties for humans, especially when administered in adequate amounts. The aim of this study was to isolate and investigate the probiotics properties of Lacticaseibacillus paracasei L2 from Lben. The isolated strain was identified by 16S r-RNA gene sequences and MALDI- TOF MS. To evaluate the probiotic potential of the isolated bacterium, in vitro tests were performed, including adhesion ability to HCT-116 cells, survival in acid and bile salt conditions, lysozyme resistance, biofilm formation, hemolytic activity, antioxidant activity, and antimicrobial activity. Our results revealed that the selected Lacticaseibacillus paracasei L2 strain expressed a high adherence to HCT-116 cells (45.03%), survived under acidic conditions (pH3), and showed a resistance to bile salts. The strain was considered as safe (α-hemolysis). L. paracasei L2 showed a high biofilm-formation ability (OD 570 > 1.7) after 24 h of incubation. It also demonstrated an important antioxidant activity in the range of 85.31% for the intact cells. However, an antimicrobial activity against pathogens, namely Staphylococcus aureus, was detected with an IZ that was above 19 mm. In conjunction with the results obtained and the technological properties of Lacticaseibacillus paracasei L2 (proteolytic property, autolytic activity, acidifying activity, and EPS production), this strain may be used as a probiotic for manufacturing fermented foods.

The Antimicrobial Effect of Various Single-Strain and Multi-Strain Probiotics, Dietary Supplements or Other Beneficial Microbes against Common Clinical Wound Pathogens

The skin is the largest organ in the human body and is colonized by a diverse microbiota that works in harmony to protect the skin. However, when skin damage occurs, the skin microbiota is also disrupted, and pathogens can invade the wound and cause infection. Probiotics or other beneficial microbes and their metabolites are one possible alternative treatment for combating skin pathogens via their antimicrobial effectiveness. The objective of our study was to evaluate the antimicrobial effect of seven multi-strain dietary supplements and eleven single-strain microbes that contain probiotics against 15 clinical wound pathogens using the agar spot assay, co-culturing assay, and agar well diffusion assay. We also conducted genera-specific and species-specific molecular methods to detect the DNA in the dietary supplements and single-strain beneficial microbes. We found that the multi-strain dietary supplements exhibited a statistically significant higher antagonistic effect against the challenge wound pathogens than the single-strain microbes and that lactobacilli-containing dietary supplements and single-strain microbes were significantly more efficient than the selected propionibacteria and bacilli. Differences in results between methods were also observed, possibly due to different mechanisms of action. Individual pathogens were susceptible to different dietary supplements or single-strain microbes. Perhaps an individual approach such as a 'probiogram' could be a possibility in the future as a method to find the most efficient targeted probiotic strains, cell-free supernatants, or neutralized cell-free supernatants that have the highest antagonistic effect against individual clinical wound pathogens.

Levilactobacillus brevis MG5311 Alleviates Ethanol-Induced Liver Injury by Suppressing Hepatic Oxidative Stress in C57BL/6 Mice

Alcoholic liver disease (ALD), caused by excessive alcohol consumption, leads to high mortality. We investigated the hepatoprotective effect of Levilactobacillus brevis MG5311 in C57BL/6 mice with liver injuries induced by chronic ethanol plus binge feeding. L. brevis MG5311 was administered orally at a dose of 1 × 10⁹ CFU/mouse once daily for 32 days. L. brevis MG5311 administration significantly reduced serum ALT, AST, and triglyceride (TG) levels in ethanol-fed mice. L. brevis MG5311 also decreased malondialdehyde levels and increased glutathione peroxidase (GPx) activity in liver tissues. In addition, hepatic TG content and histopathological scores were significantly reduced. L. brevis MG5311 increased the protein expression of SIRT1, PPARα, SOD1, CAT, and GPx 1/2 in liver tissue, while inhibiting CYP2E1 and SREBP-1c. These results indicated that L. brevis MG5311 alleviated ethanol-induced liver injury by inhibiting hepatic oxidative stress and promoting lipid metabolism. Therefore, L. brevis MG5311 may be a useful probiotic candidate for ameliorating or preventing ALD.

Ameliorative effect of Lactobacillus rhamnosus GG on acetaminophen-induced hepatotoxicity via PKC/Nrf2/PGC-1α pathway

Background

Acetaminophen (APAP) overdose is a common cause of hepatotoxicity. Antioxidants like N-acetyl cysteine are recommended as a therapeutic option; nevertheless, it has limitations. The search for efficient alternatives is ongoing. Probiotics are live microorganisms that maintain a healthy gut microecology. Lactobacillus rhamnosus GG (LGG) is one of the widely used probiotics. Our study aimed to assess the protective and therapeutic effects of probiotic LGG on APAP-induced hepatotoxicity and evaluate the molecular pathways behind this effect.

Methods

Wistar Albino male rats were randomly distributed into the following experimental groups: group 1, non-treated rats (vehicle); group 2, rats received oral gavage of suspension of probiotic LGG (5 × 10¹⁰ CFU GG/0.5 ml in PBS) daily for 2 weeks (probiotic control); group 3, rats received APAP dose of 2 g/kg body weight (positive control); group 4, rats received oral gavage of suspension of probiotic LGG for 2 weeks followed by a single dose of APAP injection (prophylactic); and group 5, rats received a single dose of APAP and then 24 h later treated with oral gavage of probiotic LGG daily for 2 weeks (treatment).

Results

Our study revealed that administration of probiotic LGG (either as prophylactic or treatment) exhibited a remarkable reduction in APAP-induced liver injury as resembled by the decrease in liver enzymes (ALT and AST) and the histopathological features of liver sections. Moreover, the significant reduction in the oxidative marker malondialdehyde, along with the enhancement in glutathione reductase, and the significant reduction in inflammatory markers (nitric oxide and tumor necrosis factor-α) were all indicators of the efficiency of LGG in ameliorating the alterations accompanied with APAP-induced hepatotoxicity. Our findings also demonstrate that LGG administration boosted the expression of Nrf2 and PGC-1 while decreasing the expression of protein kinase C (PKC). As a result, the nuclear abundance of Nrf2 is increased, and the expression of various antioxidants is eventually upregulated.

Conclusion

Our study shows that probiotic LGG supplementation exerts a prophylactic and therapeutic effect against APAP-induced hepatotoxicity through modulating the expression of PKC and the Nrf2/PGC-1α signaling pathway and eventually suppressing oxidative damage from APAP overdose.

Antioxidant and Antibacterial Effects of Potential Probiotics Isolated from Korean Fermented Foods

A total of sixteen bacterial strains were isolated and identified from the fourteen types of Korean fermented foods that were evaluated for their in vitro probiotic potentials. The results showed the highest survivability for Bacillus sp. compared to Lactobacillus sp. in simulated gastric pH, and it was found to be maximum for B. inaquosorum KNUAS016 (8.25 ± 0.08 log10 CFU/mL) and minimum for L. sakei KNUAS019 (0.8 ± 0.02 log10 CFU/mL) at 3 h of incubation. Furthermore, B. inaquosorum KNUAS016 and L. brevis KNUAS017 also had the highest survival rates of 6.86 ± 0.02 and 5.37 ± 0.01 log10 CFU/mL, respectively, in a simulated intestinal fluid condition at 4 h of incubation. The percentage of autoaggregation at 6 h for L. sakei KNUAS019 (66.55 ± 0.33%), B. tequilensis KNUAS015 (64.56 ± 0.14%), and B. inaquosorum KNUAS016 (61.63 ± 0.19%) was >60%, whereas it was lower for L. brevis KNUAS017 (29.98 ± 0.09%). Additionally, B. subtilis KNUAS003 showed higher coaggregation at 63.84 ± 0.19% while B. proteolyticus KNUAS001 found at 30.02 ± 0.33%. Among them, Lactobacillus sp. showed the best non-hemolytic activity. The highest DPPH and ABTS radical scavenging activity was observed in L. sakei KNUAS019 (58.25% and 71.88%). The cell-free supernatant of Lactobacillus sp. considerably inhibited pathogenic growth, while the cell-free supernatant of Bacillus sp. was moderately inhibited when incubated for 24 h. However, the overall results found that B. subtilis KNUAS003, B. proteolyticus KNUAS012, L. brevis KNUAS017, L. graminis KNUAS018, and L. sakei KNUAS019 were recognized as potential probiotics through different functional and toxicity assessments.

Characterization of two novel pentose-fermenting and GABA-producing species: Levilactobacillus tujiorum sp. nov. and Secundilactobacillus angelensis sp. nov. Isolated from a solid-state fermented zha-chili

Lactobacilli are dominant in zha-chili. This study provides a taxonomic characterization of five bacterial strains isolated from zha-chili in China. The cells were Gram-positive, facultative anaerobic, non-spore-forming, flagella-free, catalase-negative, heterofermentative, pentose-fermenting, and gamma-aminobutyric acid (GABA)-producing rods. For HBUAS51241T, HBUAS51329, and HBUAS51416, C16:0, C18:1ω9c and C19:0 iso were the predominant cellular fatty acids; diphosphatidylglycerol (DPG), phosphatidylglycerol (DP), glycolipids (GL), and glycolipids (AL) were the major phospholipids. While for HBUAS51383T and HBUAS58055, C16:0, C18:1ω9c, C19:0 cyclo ω8c were the predominant cellular fatty acids; DPG, DP, GL, and AL were the major phospholipids. Strains HBUAS51241T, HBUAS51329, and HBUAS51416 showed 98.1-99.1% 16S rRNA gene sequence similarity, 80.2-81.4% ANI, 87.7-90.0% AAI, and 23.8-32.8% digital DDH to their closest related type strains Levilactobacillus hammesii DSM 16381T, Levilactobacillus parabrevis ATCC 53295T, and Levilactobacillus fuyuanensis 244-4T. Strains HBUAS51383T and HBUAS58055 showed 98.7-99.5% 16S rRNA gene sequence similarity, 75.4-81.4% ANI, 75.5-89.1% AAI, and 19.7-24.0% digital DDH to their closest related type strains Secundilactobacillus silagincola IWT5T, Secundilactobacillus silagei JCM 19001T, Secundilactobacillus pentosiphilus IWT25T, Secundilactobacillus mixtipabuli IWT30T, Secundilactobacillus odoratitofui DSM 19909T, and Secundilactobacillus similis DSM 23365T. The central carbon metabolism pathways for the five strains were summarizeded. Based on the phenotypic, chemotaxonomic, and genomic data, we propose two novel species Levilactobacillus tujiorum sp. nov. whose type strain is HBUAS51241T (=GDMCC 1.3022T = JCM 35241T), and Secundilactobacillus angelensis sp. nov. whose type strain is HBUAS51383T (=GDMCC 1.3021T = JCM 35209T).

[Research Progress in the Relationship Between Lactobacillus and Dental Caries]

Lactobacillus is the first microorganism found to be closely associated with dental caries. It demonstrates acidogenicity, aciduricity, and the ability to bind with collagen and to synthesize extracellular polysaccharides to promote bacterial adhesion. Some lactobacilli inhibit the growth of cariogenic bacteria by producing antibacterial compounds or metabolites, competing with cariogenic bacteria for adhesion sites or co-aggregation, or regulating the expression of genes related to cariogenic virulence. Therefore, researchers have, in recent years, experimented with applying Lactobacillusas probiotics in the prevention and control of caries. However, the cariogenic mechanism of Lactobacillus is still not fully understood, and the potential effects, presumably beneficial, of specific Lactobacillus on oral and intestinal microecology remain unknown. More research needs to be done to combine both the cariogenic and probiotic properties of Lactobacillus, and to comprehensively evaluate the effects of Lactobacillus on oral and systemic health. We, herein, summarized research progress in the cariogenicity and caries prevention effect of Lactobacillus, focusing on a discussion of the role of Lactobacillus in cariogenesis, the development of dental caries, and clinical prevention and control of dental caries, in order to provide new ideas and references for the prevention and control of dental caries.

Correlation between metabolites of lactic acid bacteria isolated from dairy traditional fermented Tunisian products and antifungal and antioxidant activities

AIMS

The objective of this study is to identify and investigate the antifungal and antioxidant potential of lactic acid bacteria (LAB) isolated from traditional fermented products.

METHODS AND RESULTS

In this work, a collection of LAB was isolated from traditional fermented products collected in four Tunisian regions. After first screening using the overlay method, seven bacterial strains were retained due to their high antifungal effect. Four strains of Limosilactobacillus fermentum were identified, one strain of Lacticaseibacillus paracasei, one strain of Lacticaseibacillus rhamnosus and one strain of Enterococcus faecium. The antifungal as well as the antioxidant potential of these bacteria were then evaluated. Bacterial strains were effective against six fungal strains with a minimum inhibitory concentrations ranging from 25 to 100 mg/mL and a minimum fungicidal concentrations ranging from 50 to 200 mg/mL. Cell free supernatants of LAB were analyzed by HPLC-DAD and LC-MS-qTOF-MS analysis. Results showed significant production of organic acids as well as several phenolic compounds. Correlation analysis confirmed that PLA and 1,2-Dihydroxybenzene were positively correlated with antifungal potential. The results of the antioxidant activity highlighted an ABTS radical cation scavenging activity ranging from 49% to 57% and a DPPH trapping percentage ranging from 80% to 97%.

CONCLUSIONS

Therefore, due to these characteristics, identified lactic acid bacteria strains have shown their effectiveness to perform as antifungal and antioxidant agents.

SIGNIFICANCE AND IMPACT OF THE STUDY

Since microbial contamination is at the root of extensive losses in the food sector, the identified strains or their metabolites can potentially be used as additives to limit microorganism spoilage in food products and increase their shelf life.

Optimization of an Industrial Medium and Culture Conditions for Probiotic Weissella cibaria JW15 Biomass Using the Plackett-Burman Design and Response Surface Methodology

The objective of this study was to optimize industrial-grade media for improving the biomass production of Weissella cibaria JW15 (JW15) using a statistical approach. Eleven variables comprising three carbon sources (glucose, fructose, and sucrose), three nitrogen sources (protease peptone, yeast extract, and soy peptone), and five mineral sources (K₂HPO₄, potassium citrate, L-cysteine phosphate, MgSO₄, and MnSO₄) were screened by using the Plackett-Burman design. Consequently, glucose, sucrose, and soy peptone were used as significant variables in response surface methodology (RSM). The composition of the optimal medium (OM) was 22.35 g/l glucose, 15.57 g/l sucrose, and 10.05 g/l soy peptone, 2.0 g/l K₂HPO₄, 5.0 g/l sodium acetate, 0.1 g/l MgSO₄·7H₂O, 0.05 g/l MnSO₄·H₂O, and 1.0 g/l Tween 80. The OM significantly improved the biomass production of JW15 over an established commercial medium (MRS). After fermenting OM, the dry cell weight of JW15 was 4.89 g/l, which was comparable to the predicted value (4.77 g/l), and 1.67 times higher than that of the MRS medium (3.02 g/l). Correspondingly, JW15 showed a rapid and increased production of lactic and acetic acid in the OM. To perform a scale-up validation, batch fermentation was executed in a 5-l bioreactor at 37°C with or without a pH control at 6.0 ± 0.1. The biomass production of JW15 significantly improved (1.98 times higher) under the pH control, and the cost of OM was reduced by two-thirds compared to that in the MRS medium. In conclusion, OM may be utilized for mass producing JW15 for industrial use.

Effects of Resistant Dextrin from Potato Starch on the Growth Dynamics of Selected Co-Cultured Strains of Gastrointestinal Bacteria and the Activity of Fecal Enzymes

Preparations of resistant dextrins have become an interesting topic of research due to their properties, which bear resemblance those of prebiotics, e.g., the improvement of metabolic parameters, increased efficiency of the immune system and induction of vitamin production. The aim of this study was to investigate the effects of the resistant dextrin produced from potato starch on the growth dynamics of typical gastrointestinal microbiota and the activity of fecal enzymes in order to assess a possible exhibition of prebiotic properties. In the study, in vitro cultivation of co-cultures of Lactobacillus, Bifidobacterium, E. coli, Enterococcus, Clostridium and Bacteroides spp. was conducted on media enriched with the resistant dextrin. The CFU/mL for each strain was measured in time periods of 24, 48, 72, 96 and 168 h. Furthermore, the activities of α-glucosidase, α-galactosidase, β-glucosidase, β-galactosidase and β-glucuronidase were determined using spectrophotometric methods at a wavelength of 400 nm. The results show that the resistant dextrin can be utilized as a source of carbon for the growth of intestinal bacteria. Moreover, the results revealed that, after 168 h of cultivation, it enhances the viability of probiotic strains of Lactobacillus and Bifidobacterium spp. and decreases the growth of other intestinal strains (Clostridium, Escherichia coli, Enterococcus and Bacteroides), which is demonstrated by a high Prebiotic Index (p < 0.05). Furthermore, there was no significant change in the pH of the cultures; however, the pace of the pH decrease during the cultivation was slower in the case of culture with resistant dextrin. Furthermore, it was revealed that usage of the resistant dextrin as a medium additive noticeably lowered the activities of β-glucosidase and β-glucuronidase compared to the control (p < 0.05), whereas the activities of the other fecal enzymes were affected to a lesser degree. The resistant dextrins derived from potato starch are a suitable prebiotic candidate as they promote the growth of beneficial strains of gut bacteria and improve health markers, such as the activity of fecal enzymes. Nevertheless, additional in vivo research is necessary to further assess the suspected health-promoting properties.

Physicochemical analysis of non-fermented probiotic milk with probiotic Lactobacillus plantarum Ln1 isolated from Korea traditional fermented food

The objective of this study was to develop a non-fermented probiotic milk that maintains its physicochemical properties, microbial properties, antioxidant activity, and sensory properties during storage (0, 7, and 14 days). During storage, pH and viable cell counts decreased; however, titratable acidity increased. In addition, the composition and sensory characteristics of the non-fermented probiotic milk showed no significant differences between samples (MLN; milk with Lactobacillus plantarum Ln1, MGG; milk with Lactobacillus rhamnosus GG, and milk control). The antioxidant activities of MLN determined using 2,2-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging, ABTS⁺ radical scavenging, and reducing power assay were higher during the examined storage periods when compared with those of the other samples. Overall, the physicochemical properties, microbial properties, and sensory factors of MLN showed no significant differences. However, high antioxidant activity was observed. Thus, we present a new functional dairy product with antioxidant activity.

Protective Effects of a Novel Lactobacillus brevis Strain with Probiotic Characteristics against Staphylococcus aureus Lipoteichoic Acid-Induced Intestinal Inflammatory Response

Probiotics can effectively modulate host immune responses and prevent gastrointestinal diseases. The objective of this study was to investigate the probiotic characteristics of Lactobacillus brevis KU15152 isolated from kimchi and its protective potential against intestinal inflammation induced by Staphylococcus aureus lipoteichoic acid (aLTA). L. brevis KU15152 exhibited a high survival rate in artificial gastric and bile environments. Additionally, the adhesion capability of the strain to HT-29 cells was higher than that of L. rhamnosus GG. L. brevis KU15152 did not produce harmful enzymes, such as β-glucuronidase, indicating that it could be used as a potential probiotic. The anti-inflammatory potential of L. brevis KU15152 was determined in HT-29 cells. Treatment with L. brevis KU15152 suppressed the production of interleukin-8 without inducing significant cytotoxicity. The downregulatory effects of L. brevis KU15152 were involved in the suppression of nuclear factor-kappa B activation mediated by the extracellular signal-regulated kinase and Akt signaling pathways. Collectively, these data suggest that L. brevis KU15152 can be used in developing therapeutic and prophylactic products to manage and treat aLTA-induced intestinal damage.

Antibacterial and Antibiofilm Effect of Cell-Free Supernatant of Lactobacillus brevis KCCM 202399 Isolated from Korean Fermented Food against Streptococcus mutans KCTC 5458

This study aims to determine the antibiofilm effect of cell-free supernatant (CFS) of Lactobacillus brevis strains against Streptococcus mutans strains. To study the antibiofilm mechanism against S. mutans strains, antibacterial effects, cell surface properties (auto-aggregation and cell surface hydrophobicity), exopolysaccharide (EPS) production, and morphological changes were examined. The antibiofilm effect of L. brevis KCCM 202399 CFS as morphological changes were evaluated by scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM), compared with the control treatment. Among the L. brevis strains, L. brevis KCCM 202399 showed the highest antibiofilm effect on S. mutans KCTC 5458. The antibacterial effect of L. brevis KCCM 202399 against S. mutans KCTC 5458 was investigated using the deferred method (16.00 mm). The minimum inhibitory concentration of L. brevis KCCM 202399 against S. mutans KCTC 5458 was 25.00%. Compared with the control treatment, L. brevis KCCM 202399 CFS inhibited the bacterial adhesion of S. mutans KCTC 5458 by decreasing auto-aggregation, cell surface hydrophobicity, and EPS production (45.91%, 40.51%, and 67.44%, respectively). L. brevis KCCM 202399 CFS inhibited and eradicated the S. mutans KCTC 5458 biofilm. Therefore, these results suggest that L. brevis KCCM 202399 CFS may be used to develop oral health in the probiotic industry.

Effects of the Probiotic Lactiplantibacillus plantarum KU15120 Derived from Korean Homemade Diced-Radish Kimchi Against Oxidation and Adipogenesis

Intestinal microflora can influence abnormal adipocyte growth. Therefore, this study was aimed to investigate the probiotic properties and antioxidant and antiobesity effects of isolated strains from homemade kimchi. Among the isolated strains, Lactiplantibacillus plantarum KU15120 showed high tolerance to artificial gastric juice and bile salt conditions, high adhesion to HT-29 cells, nonproduction of β-glucuronidase, nonhemolysis, and acceptable resistance to antibiotics. It showed high antioxidant activity, including DPPH and ABTS radical scavenging and antioxidant activity, as determined by the β-carotene bleaching assay. Oil red O staining and intracellular triglyceride levels revealed reduced lipid accumulation, which confirmed the anti-adipogenic activity of L. plantarum KU15120. In addition, the expression levels of fatty acid synthase, CCAAT/enhance-binding protein α, and peroxisome proliferator-activated receptor γ, were significantly lower in the probiotic-treated group than in the control group. These results suggest that L. plantarum KU15120 has probiotic properties, antioxidant, and antiobesity effects and could be used as a therapeutic probiotics.

Probiotic Characteristics of Lactobacillus brevis KT38-3 Isolated from an Artisanal Tulum Cheese

Probiotics are living microorganisms that, when administered in adequate amounts, provide a health benefit to the host and are considered safe. Most probiotic strains that are beneficial to human health are included in the “Lactic acid bacteria” (LAB) group. The positive effects of probiotic bacteria on the host’s health are species-specific and even strain-specific. Therefore, evaluating the probiotic potential of both wild and novel strains is essential. In this study, the probiotic characteristics of Lactobacillus brevis KT38-3 were determined. The strain identification was achieved by 16S rRNA sequencing. API-ZYM test kits were used to determine the enzymatic capacity of the strain. L. brevis KT38-3 was able to survive in conditions with a broad pH range (pH 2–7), range of bile salts (0.3%–1%) and conditions that simulated gastric juice and intestinal juice. The percentage of autoaggregation (59.4%), coaggregation with E. coli O157:H7 (37.4%) and hydrophobicity were determined to be 51.1%, 47.4%, and 52.7%, respectively. L. brevis KT38-3 produced β-galactosidase enzymes and was able ferment lactose. In addition, this strain was capable of producing antimicrobial peptides against the bacteria tested, including methicillin and/or vancomycin-resistant bacteria. The cell-free supernatants of the strain had high antioxidant activities (DPPH: 54.9% and ABTS: 48.7%). Therefore, considering these many essential in vitro probiotic properties, L. brevis KT38-3 has the potential to be used as a probiotic supplement. Supporting these findings with in vivo experiments to evaluate the potential health benefits will be the subject of our future work.

Anti-adipogenic Effects of the Probiotic Lactiplantibacillus plantarum KU15117 on 3T3-L1 Adipocytes

In this study, we investigated the probiotic properties and anti-obesity effects of bacterial strains isolated from homemade kimchi. Lactiplantibacillus plantarum KU15117 was isolated using lactobacilli selective medium. L. plantarum KU15117 did not produce β-glucuronidase and showed high tolerance to artificial gastric juice and bile salt, acceptable resistance to antibiotics, and high adhesion ability to HT-29 cells. The anti-adipogenic activity of L. plantarum KU15117 at 10⁹ CFU/well was confirmed by the reduction of oil red O staining and intracellular triglyceride level. Additionally, the expression levels of fatty acid synthase, CCAAT/enhance-binding protein-α, and peroxisome proliferator-activated receptor-γ, which are associated with the early stage of adipocyte differentiation, were significantly lower in the probiotic-treated group than in the control group. These results suggest that L. plantarum KU15117 has probiotic properties and anti-obesity effects and could be used as a prophylactic probiotics.

Prophylactic effects of probiotics on respiratory viruses including COVID-19: a review

Coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is mainly transmitted through respiratory droplets. The symptoms include dry cough, fever, and fatigue; however, high propagation, mutation, and fatality rates have been reported for SARS-CoV-2. This review investigates the structure of SARS-CoV-2, antiviral mechanisms, preventive strategies, and remedies against it. Effective vaccines have been developed by Pfizer (95% effective), AstraZeneca (90% effective), Moderna (94.5% effective) vaccine, among others. However, herd immunity is also required. Probiotics play a major role in the gut health, and some are known to have therapeutic potential against viral infections. Their modes of antiviral activities include direct interaction with targeted viruses, production of antiviral metabolites, and immunomodulatory effects on the host. Hence, probiotics can be a useful prophylactic against COVID-19, and more studies are required on the effects of probiotics against other viral infections that may occur in future.

Inhibitory effects of Lactobacillus brevis KU15153 against Streptococcus mutans KCTC 5316 causing dental caries

This study determined the inhibitory effect of Lactobacillus brevis KU15153 against cariogenic Streptococcus mutans KCTC 5316. Antimicrobial activity, auto-aggregation, cell surface hydrophobicity, exopolysaccharides (EPS) production, biofilm formation, and morphological changes were assessed in the presence of L. brevis KU15153. L. brevis KU15153 exhibited the highest antimicrobial activity against S. mutans KCTC 5316 (28.67 ± 4.16 mm). Auto-aggregation (38.32%), cell surface hydrophobicity (27.08%), and EPS production rate (58.52%) of S. mutans KCTC 5316 slightly decreased upon treatment with L. brevis KU15153. Additionally, crystal violet stanning and scanning electron microscopy confirmed the L. brevis KU15153-mediated inhibition of biofilm formation by S. mutans KCTC 5316 in comparison to that observed in the negative control (untreated S. mutans KCTC 5316). These results indicate that the L. brevis KU15153 could be used as a potential probiotic for maintaining oral health.

Antipathogenic and probiotic potential of Lactobacillus brevis strains newly isolated from Algerian artisanal cheeses

From 98 Lactobacillus strains, isolated from Algerian homemade cheeses, 14 (B1-B14) were selected based on their anti-Escherichia coli and anti-Staphylococcus aureus activities. These strains were also tested towards Listeria monocytogenes 161 and Salmonella Typhimurium LT2 and further investigated for their resistance to simulated gastrointestinal digestion, cell surface properties, ability to adhere to HT-29 cells, cholesterol lowering, antioxidant activity, and technological traits. Five isolates (B9, B13, B18, B19, and B38) were active against L. monocytogenes and Salmonella. From them, three isolates, identified as Lactobacillus brevis (B9, B13, and B38) by MALDI-TOF spectrometry and 16S rDNA sequencing, exhibited high tolerance to pancreatic juice, bile salts and acidic juices, high percentages of hydrophobicity (87, 92, and 81%, respectively), auto-aggregation (61, 68, and 72%, respectively), and adherence to HT-29 cells (79, 84, and 74%, respectively), which testify on their potential of colonization of the human intestine. On the other way, the strains B9 and B13 manifested the most relevant antioxidant activity and cholesterol-lowering ability, respectively. L. brevis strains showed low acidifying and good proteolytic activities with noticeable heat tolerance. The results gathered in this study highlighted the richness of Algerian artisanal cheeses on new lactobacilli strains with an excellent probiotic potential and demonstrated that L. brevis, largely used as nonstarter in cheese manufacture, could be exploited also as a probiotic for human use.

Physicochemical Analysis of Yogurt Produced by Leuconostoc mesenteroides H40 and Its Effects on Oxidative Stress in Neuronal Cells

Leuconostoc mesenteroides H40 (H40) was isolated from kimchi, and its probiotic properties and neuroprotective effect was evaluated in oxidatively stressed SH-SY5Y cells. H40 was stable in artificial gastric conditions and can be attached in HT-29 cells. In addition, H40 did not produce β-glucuronidase and showed resistant to several antibiotics. The conditioned medium (CM) was made using HT-29 cells refined with heat-killed probiotics (Probiotics-CM) and heated yogurts (Y-CM) to investigate the neuroprotective effect. Treatment with H40-CM not only increased cell viability but also significantly improved brain derived neurotropic factor (BDNF) expression and reduced the Bax/Bcl-2 ratio in oxidatively stress-induced SH-SY5Y cells. Besides, probiotic Y-CM significantly increased BDNF mRNA expression and decreased Bax/Bcl-2 ratio. The physicochemical properties of probiotic yogurt with H40 was not significantly different from the control yogurt. The viable cell counts of lactic acid bacteria in control and probiotic yogurt with H40 was 8.66 Log CFU/mL and 8.96 Log CFU/mL, respectively. Therefore, these results indicate that H40 can be used as prophylactic functional dairy food having neuroprotective effects.

Antimicrobial and anti-biofilm effects of probiotic Lactobacillus plantarum KU200656 isolated from kimchi

The probiotic properties and anti-pathogenic effects of Lactobacillus plantarum KU200656 (KU200656) isolated from Korean fermented kimchi against Staphylococcus aureus, Listeria monocytogenes, Escherichia coli, and Salmonella Typhimurium were investigated. KU200656 showed high tolerance to artificial gastric acid (99.48%) and bile salts (102.40%) and this strain was safe according to antibiotic sensitivity test; it could not produce harmful enzymes, including β-glucuronidase. KU200656 exhibited high adhesion (4.45%) to intestinal cells, HT-29 cells, with high cell surface hydrophobicity (87.31% for xylene and 81.11% for toluene). Moreover, KU200656 co-aggregated with pathogenic bacteria and exhibited antibacterial activity and anti-adhesion properties against pathogens. The cell-free supernatant (CFS) of KU200656 inhibited biofilm formation by pathogenic bacteria. In addition, half of the minimum inhibitory concentration of the KU200656 CFS downregulated the expression of biofilm-related genes, as determined by quantitative real-time PCR. Therefore, KU200656 was demonstrated to possess anti-pathogenic effects and have potential for use as probiotics in the food industry.

Probiotic Potential and Gluten Hydrolysis Activity of Lactobacillus brevis KT16-2

Celiac disease (CD) is a chronic autoimmune disease that occurs in genetically predisposed individuals. Gluten-hydrolyzing probiotic bacteria are promising for alleviating symptoms in individuals with CD. Therefore, in this study, the gluten hydrolysis ability and probiotic potential of Lact. brevis KT16-2 were determined. Lact. brevis KT16-2 formed proteolysis zones on gluten and gliadin agar plates, in which gluten and gliadin were used as the only nitrogen sources. SDS-PAGE analysis showed that Lact. brevis KT16-2 completely hydrolyzed peptides ranging from 28 to 66 kDa in 8 h. Then, the survival of the strain in bile salts, in simulated gastric juice and at low pH was determined. Additionally, the antioxidant and antimicrobial substance production, autoaggregation, hydrophobicity and antibiotic resistance of the strain were investigated. API-ZYM test kits were used to determine the enzymatic capacity of the strain. Lact. brevis KT16-2 had the ability to hydrolyze wheat gluten. It was able to survive in a broad pH range (pH 2-8), in bile salts (0.3-1%), and in simulated gastric juice. It had the ability to autoaggregate (59.4%), and the hydrophobicity (52.7%) of the strain was determined. In addition, this strain was capable of producing antimicrobial peptides against test bacteria, including antibiotic-resistant bacteria. Cell-free supernatants (CFS) of the strain had high antioxidant activity (DPPH-71.0% and ABTS-54.1%). The results of this study suggest that Lact. brevis KT16-2, which can hydrolyze gliadin and has many essential probiotic properties, has the potential to be used as a probiotic supplement for individuals with CD.

Fermented dairy products as delivery vehicles of novel probiotic strains isolated from traditional fermented Asian foods

The screening of novel probiotic strains from various food sources including fruits, vegetables, herbs, and traditional fermented foods, have been of growing concern recently. Most of these potential probiotic lactic acid bacteria isolates were distinguished from the commercial probiotics based on multiple therapeutic effects and functionalities. Recent in vitro and in vivo investigates have also verified the usage of probiotics to lower the risk of diseases. Application of these novel strains in fermented dairy products is also an emerging trend to improve the physical and quality characteristics, functional properties, and safety of dairy products. Moreover, since dairy products are one of the highest consumed products in the globe, the dispatch channels for fermented dairy products are already established. Therefore, incorporating novel probiotic strains into fermented dairy products might be the most feasible approach for their delivery. In this context, our aim is to discuss the feasibility of dairy products as delivery vehicles for novel probiotic strains. Thus, we summarize the scientific evidence that points to a dynamic future for the production of fermented dairy-based probiotics.

Clusters of Lactobacillus Strains from Vegetal Origins Are Associated with Beneficial Functions: Experimental Data and Statistical Interpretations

Nine strains of Lactiplantibacillus plantarum and one strain of Lacticaseibacillus paracasei that were recently isolated from prickly pears, fresh figs and blackberries, which are traditionally and largely consumed fruits in Kabylia (north of Algeria), were studied here for their antagonism and antioxidant properties as well as for production of exopolysaccharides. With respect to their inhibitory properties, these strains were tested against three food representative pathogens including Escherichia coli ATCC 8739, Staphylococcus aureus 2S6 and Listeria monocytogenes 162. The antagonism of these pathogens was attributable to lactic acid production, present in the cell free supernatant, at concentrations ranging from 9 to 16.74 g/L. The anti-adhesive properties observed on polystyrene or eukaryotic Caco-2 cells were exerted in a strain dependent-manner. Indeed, the scores obtained ranged from 27% to 75% for S. aureus 2S6, 54% to 95% for L. monocytogenes 162, and 50% to 97% for E. coli ATCC 8739. The co-aggregation of these Lactobacillus strains with the aforementioned target bacteria appeared to be exerted in a strain-dependent manner, with noticeably the upmost rate for Lb. paracasei FB1 on S. aureus 2S6. Interestingly, these novel Lactobacillus strains were able to produce a large amount (315.55 to 483.22 mg/L) of exopolysaccharides, and showed a significant scavenging activity on the 2,2-di-phényl-2-picrylhydrazyle (DPPH) synthetic free radical with rates of 51% to 56%. Of note, the highest antioxidant activity was observed for Lb. paracasei FB1 using the culture supernatants, intact cells or the intracellular extract. The statistical analysis of these data using the principal component analysis (ACP) enabled us to establish three distinct clusters with potential applications as bioprotective and/or probiotic agents, following further evaluation.