Search Results (114)

In this study, 62 lactic acid bacteria (LAB) strains were isolated from raw camel milk and evaluated for their probiotic potential. The strains exhibited significant variability in their ability to withstand simulated gastrointestinal conditions. Of the isolates, only 26 survived exposure to pH 2, and just 10 were tolerant to 0.3% bile salts. Partial sequencing of the 16S rRNA gene identified all the strains as belonging to the species Enterococcus faecium. Several probiotic traits were assessed, including adhesion to gastric mucin and STC-1 intestinal epithelial cells, as well as auto-aggregation and co-aggregation capacities. Although adhesion to hydrophobic solvents such as chloroform and ethyl acetate was generally low to moderate, all the strains demonstrated strong adhesion to gastric mucin, exceeding 60% at all the growth stages. Notably, two strains—SCC1-33 and SLch6—showed particularly high adhesion to STC-1 cells, with values of 7.8 × 10³ and 4.2 × 10³ CFU/mL, respectively. The strains also exhibited promising aggregation properties, with auto-aggregation and co-aggregation ranging between 33.10% and 63.10%. Furthermore, all the isolates displayed antagonistic activity against Listeria innocua, Micrococcus luteus, and Escherichia coli. Cytotoxicity assays confirmed that none of the tested strains had harmful effects on STC-1 cells, indicating their safety and supporting their potential application as probiotics. Full article

Lactic acid bacteria (LAB) preserve many foods and play a vital role in fermented food products. This study designed a controlled biotechnological process of catfish (Clarias gariepinus) fermentation with a LAB starter culture isolated from corn hydrolysate. The BY (Barbu-Yelouassi) LAB strain was characterized regarding fermentative and antimicrobial potential, and its adaptability in the simulated gastrointestinal system (SGIS). After 10–12 h of cultivation on MRS broth (De Man Rogosa and Sharpe), the strain achieved the maximum exponential growth, produced maximum lactic acid (33.04%), and decreased the acidity up to pH 4. Also, the isolated strain showed increased tolerance to an acidic pH (3.5–2.0), high concentrations of salt (2–10%), and high concentrations of bile salts (≤2%). The behavior in SGIS demonstrated good viability after 2 h in artificial gastric juice (AGJ) (1 × 10⁷ CFU/mL) and up to 2 × 10³ CFU/mL after another 6 h in artificial intestinal juice (AIJ). The characterized BY strain was identified with the API 50CHL microtest (BioMerieux) as Lactiplantibacillus pentosus (Lbp. pentosus) (90.9% probability), taxon confirmed by genomic DNA sequencing. It was also demonstrated that Lbp. pentosus BY inhibited the growth of pathogenic bacteria, including Escherichia coli, Staphylococcus aureus, Listeria monocytogenes, and sporulated bacteria, such as Bacillus cereus. Additionally, it suppressed the sporulation of fungi like Aspergillus niger, Fusarium sp., and Penicillium sp. Furthermore, the Lbp. pentosus BY strain was used to ferment catfish, resulting in three variants of lanhouin (unsalted, with 10% salt, and with 15% salt), which exhibited good microbiological safety. Full article

Gamma-aminobutyric acid (GABA) is a non-protein amino acid playing a significant role in the central nervous system and the gut–brain axis. This study investigated the potential to produce GABA by lactic acid bacteria (LAB) isolated from different varieties of organic tomatoes. The isolated LAB were taxonomically identified by 16S rRNA gene sequencing, the presence of the gadB gene (glutamate decarboxylase) was detected, and GABA production was quantified using HPLC. Levilactobacillus brevis CRAI showed the highest GABA production under optimised fermentation conditions with 4% monosodium glutamate (MSG). The genome sequencing of L. brevis CRAI revealed the presence of gadA and gadB isoforms and assessed the strain’s safety profile. The gene expression analysis revealed that the gadA and gadB genes were upregulated in the presence of 4% MSG. The probiotic potential of L. brevis CRAI was also assessed by functional assays. The strain showed strong antimicrobial activity against representative enteropathogens, i.e., Escherichia coli ETEC, Salmonella choleraesuis, and Yersinia enterocolitica, and anti-inflammatory effect, reducing nitric oxide production in LPS-stimulated RAW264.7 macrophages. In addition, its ability to adhere to intestinal epithelial Caco-2 cells was demonstrated. These results highlight L. brevis CRAI as a promising candidate for the development of GABA-enriched functional foods or probiotic supplements with the perspective to modulate the gut-brain axis. Full article

Antibiotic overuse has contributed to the emergence of multidrug-resistant (MDR) bacteria, posing a serious public health threat. Pets may act as reservoirs of MDR bacteria, with the potential to transmit these pathogens to humans. This study aimed to identify probiotic alternatives to antibiotics by isolating and evaluating lactic acid bacteria (LAB) from feline milk. In addition to conventional in vitro assessments such as growth kinetics, adhesion ability, safety, and antipathogenic activity, this study also evaluated the antioxidant capacity and production of beneficial metabolites. Three LAB strains were isolated from feline milk, including two strains of Lactobacillus plantarum (M2 and M3) and one strain of Weissella confusa (M1). Resistance assays revealed that strains M2 and M3 exhibited high survival rates under stress conditions, including exposure to bile salts, acidic environments, artificial intestinal and gastric juice. Notably, strain M3 demonstrated strong auto-aggregation ability (73.39%) and high hydrophobicity toward trichloromethane (62.16%). It was also nonhemolytic and susceptible to various β-lactam antibiotics. Furthermore, strain M3 exhibited potent antimicrobial activity in both co-aggregation and Oxford cup assays. Overall, L. plantarum M3 displayed superior probiotic properties, suggesting its potential as an adjunct or alternative to antibiotics in managing MDR bacterial infections in cats. Full article

Aminopeptidase N (APN), an enzyme expressed in the small intestinal mucosa, is involved in dietary protein digestion. Previous studies have shown that oral administration of fermented milk containing lactic acid bacteria (LAB) enhances mucosal APN activity in young mice. This study aimed to investigate whether LAB strains stimulate mucosal APN activity in aged mice and to evaluate its relevance to age-related changes in body composition. The underlying molecular mechanisms were also explored in vitro. Experiment 1: Aged C57BL/6J mice were fed diets supplemented with heat-killed LAB strains—Enterococcus faecalis OU-23 (EF), Leuconostoc mesenteroides OU-03 (LM), or Lactiplantibacillus plantarum SNK12 (LP). Compared to the aged Control group, the ileal APN activity was significantly higher in the LP group. LP administration also elevated serum Gla-osteocalcin levels and decreased serum CTX-1 levels. Experiment 2: IEC-6 cells were co-cultured with LP that had been treated with RNase, DNase, or lysozyme. APN activity was significantly lower in cells co-cultured with DNase- or lysozyme-treated LP compared to those co-cultured with untreated LP. A specific LAB strain may enhance mucosal APN activity in the aged intestine, potentially contributing to improved bone metabolism. This effect may be mediated by bacterial DNA and peptidoglycan. Full article

Background/Objectives: The overuse and misuse of antibiotics has contributed significatively to the growing problem of the emergence and spread of antibiotic resistance genes among bacteria, posing a serious global challenge to the treatment of bacterial infectious diseases. For these reasons, there is a current and growing interest in the development of effective alternative or complementary strategies to antibiotic therapy for the prevention of fish diseases, which are mainly based on the use of probiotics—in particular, those belonging to the Lactic Acid Bacteria (LAB) group. In this context, the aim of the present study was to characterise, evaluate the genetic diversity and assess the safety of candidate probiotic LAB strains for aquaculture isolated from faeces and intestines of European hakes (Merluccius merluccius, L.) caught in the Northeast Atlantic Ocean (Ireland). Methods: The direct antimicrobial activity of the LAB isolates was tested by the Stab-On-Agar method against key ichthyopathogens. Subsequently, their taxonomic classification and genetic diversity were determined by 16SrDNA sequencing and Enterobacterial Repetitive Intergenic Consensus-PCR (ERIC-PCR), respectively. To ensure the in vitro safety of the LAB isolates, their biofilm-forming ability was assessed by a microtiter plate assay; their sensitivity to major antibiotics used in aquaculture, human and veterinary medicine by a broth microdilution method and their haemolytic and gelatinase activity by microbiological assays. Results: All LAB isolates were biofilm producers and susceptible to chloramphenicol, oxytetracycline, flumequine and amoxicillin. A total of 30 isolates (85.7%) were resistant to at least one of the tested antibiotics. None of the 35 LAB isolates showed haemolytic or proteolytic activity. Conclusions: Among the isolated strains, five LAB strains exhibiting the highest antimicrobial activity against aquaculture-relevant ichthyopathogens, taxonomically identified as Streptococcus salivarius, Enterococcus avium and Latilactobacillus sakei, were selected for further characterisation as potential probiotic candidates to promote sustainable aquaculture. To our knowledge, this is the first study to report that hake intestines and faeces represent viable ecological niches for the isolation of LAB strains with antimicrobial activity. Full article

This study investigates the potential of blackberry juice fortified with whey as a carrier for transporting and protecting lactic acid bacteria (LAB). The interactions between whey proteins and the juice were examined to assess their impact on probiotic stability and protection during storage and passage through the gastrointestinal tract. Additionally, the study explored how this combination influences the antioxidant properties of the product. The results indicated that the blackberry juice and whey protein mixture provided moderate protection to Lacticaseibacillus rhamnosus GG compared to the positive control (inulin), suggesting that whey proteins may enhance probiotic viability. Proteolytic analysis revealed progressive protein hydrolysis during fermentation, leading to the release of bioactive peptides, indicating the formation of compounds with potential functional benefits. Moreover, samples inoculated with LAB exhibited higher antioxidant activity than those without inoculum. This research demonstrates the promise of fermented blackberry juice fortified with whey proteins as an effective probiotic delivery system. It opens new possibilities for developing functional foods to promote intestinal health and overall well-being. Full article

Background/Objectives: The deterioration of food quality and safety is often linked to the presence of pathogenic and spoilage microorganisms. Postbiotics, including organic acids, enzymes, and bacteriocins produced by lactic acid bacteria (LAB), have emerged as promising next-generation food preservatives. This study investigates the biological and physicochemical properties of several postbiotic-based extracts (PBEs) comprising cell-free supernatant (CFS) and exopolysaccharide (EPS) fractions derived from three native probiotic strains: Lactiplantibacillus plantarum UTNGt2, Lactococcus lactis UTNGt28, and Weissella cibaria UTNGt21O. Methods: The antibacterial activity of these PBEs was assessed against multidrug-resistant Escherichia coli L1PEag1. Moreover, the antioxidant capacity and cytotoxicity along with the characterization of these formulations was assessed. Results: FU6 (CFS UTNGt28: EPS UTNGt2) and FU13 (CFS UTNGt21O) were found as the most potent formulations. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) confirmed dose- and time-dependent damage to the bacterial membrane and cell wall. FU6 exhibited superior antioxidant activity and lacked hemolytic effects, whereas both FU6 and FU13 induced cell-specific responses in HEK293 (human kidney) and HT-29 (intestinal mucus-producing) cell lines. Furthermore, attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy identified characteristic absorption bands corresponding to proteins, lipids, carbohydrates, and nucleic acids, while proton nuclear magnetic resonance (¹H-NMR) spectroscopy revealed key monosaccharides, amino acids, and metabolites such as lactate and acetate within the extracts. Conclusions: FU6 and FU13 demonstrate potential as safe and effective postbiotic formulations at non-concentrated doses. However, further research is required to elucidate their molecular composition comprehensively and evaluate their applicability for broader and long-term use in food preservation and pharmaceutical development. Full article

Since 2022, the European Union has banned the use of antibiotics in animal production. We conducted studies to characterize Lactiplantibacillus plantarum (47, AN8, and OK-B) and Ligilactobacillus salivarius (AN9) and evaluate their potential to create a biopreparation based on fermented whey for chickens. The following methods were used: lactic acid bacteria (LAB) culture and storage, crystal violet staining, Koch’s plate method, Caco-2 cell culture, hydrophobicity test, and spectrophotometric measurements. All bacteria showed weak adhesion to polystyrene and collagen, and the L. plantarum species demonstrated weak adhesion to mucus. All bacteria showed strong adhesion to the intestinal epithelial cell line Caco-2. LAB showed strong autoaggregation and coaggregation with E. coli ATCC10536. The highest affinity for xylene was exhibited by L. salivarius AN9 (above 30%) while, for chloroform, the highest affinity was exhibited by L. plantarum OK-B (approx. 95%); the affinity for n-hexadecane for all strains was below 20%. The highest survival in the presence of bile salts (0.3%) was demonstrated by L. plantarum 47 (above 54%). The effect of low pH resulted in decreased viability for all strains. Significant differences were demonstrated in the concentration of lactic acid between MRS and whey medium after culturing LAB. These results will aid in qualifying these strains for further research to create a functional feed for chickens. Full article

The purpose of this research is to identify and characterize lactic acid bacteria (LAB) species in bee bread produced by honey bees (Apis Cerana) in the east mountain area of Suzhou, China. We isolated three strains, Apilactobacillus kunkeei (S1), Lactiplantibacillus plantarum (S2), and Lacticaseibacillus pentosus (S3), with S2 producing the highest amount of lactic acid. Phylogenetic analysis indicated that these isolates, along with the type strain, formed a distinct sub-cluster within the LAB group. The strains exhibited non-hemolytic activity, lacked functional virulence factors, demonstrated high acid and bile tolerance, strong adhesion to intestinal cells, and antimicrobial activity against pathogens, collectively indicating their safety and high probiotic potential for therapeutic applications. Our studies demonstrated that S2 and S3 grew well in the presence of stevia leaf powder and steviosides, while S1 showed reduced growth and inhibitory effects. Importantly, the stevia-fermented strains exhibited strong probiotic potential along with significant antidiabetic, antioxidant, and antifungal properties in vitro. These findings highlight their potential applications in the food, feed, and pharmaceutical industries. Future research should focus on in vivo experiments to validate these results and evaluate compatibility among the strains before their application in functional foods. Full article

This study evaluated the probiotic potential of lactic acid bacteria (LAB) isolated from fermented milk and soymilk products purchased from local markets. The LAB strains were assessed for acid and bile resistance, antibiotic resistance, and adhesion to human intestinal epithelial models. Streptococcus thermophilus (JAMI_LB_02) and Lactiplantibacillus plantarum (JAMI_LB_05) showed the highest survival rates in artificial gastric and bile juices, at 87.17 ± 0.02% and 96.71 ± 4.10%, respectively, with all strains (except JAMI_LB_03) demonstrating antibiotic resistance. Adhesion ability indicated the superior performance of JAMI_LB_02 and JAMI_LB_05 compared to standard strains. JAMI_LB_02 adhered to Caco-2 cells at 2.10 ± 0.94% and to HT-29 cells at 3.32 ± 0.38%, exceeding standard strains (1.06 ± 0.13% and 1.89 ± 0.58%). JAMI_LB_05 achieved the highest rates at 5.62 ± 1.33% on Caco-2 and 5.76 ± 0.46% on HT-29 cells. Their combination (JAMI_LB_02 + JAMI_LB_05) significantly enhanced adhesion to 18.57 ± 5.49% on Caco-2 and 21.67 ± 8.19% on HT-29 cells, demonstrating strong synergy. These findings highlight the probiotic potential of the isolated LAB strains, particularly in mixed formulations, which may improve intestinal survival, adaptability, and efficacy. Further in vivo studies are warranted to validate their clinical applications and optimize strain combinations for human health benefits. Full article

Bacteriocins produced by lactic acid bacteria (LAB) are promising bioactive peptides. Intriguingly, bacteriocins have health benefits to the host and may be applied safely in the food industry as bio-preservatives or as therapeutic interventions preventing intestinal diseases. In recent years, finding a safe alternative approach to conventional treatments to promote gut health is a scientific hotspot. Therefore, this review aimed to give insight into the promising applications of LAB-bacteriocins in preventing intestinal diseases, such as colonic cancer, Helicobacter pylori infections, multidrug-resistant infection-associated colitis, viral gastroenteritis, inflammatory bowel disease, and obesity disorders. Moreover, we highlighted the recent research on bacteriocins promoting gastrointestinal health. The review also provided insights into the proposed mechanisms, challenges and opportunities, trends and prospects. In addition, a SWOT analysis was conducted on the potential applications. Based on properties, biosafety, and health functions of LAB-bacteriocins, we conclude that the future applications of LAB-bacteriocins are promising in promoting gastrointestinal health. Further in vivo trials are needed to confirm these potential effects of LAB-bacteriocins interventions. Full article

This study explores the biocontrol potential of Pediococcus sp. M21F004, a lactic acid bacteria (LAB) isolated from marine environments, against several bacterial and fungal phytopathogens. Out of 50 marine bacterial isolates, Pediococcus sp. M21F004 was selected for its exceptional antimicrobial activity. The strain, isolated from the intestine of a starry flounder, was identified as Pediococcus sp. Gas chromatography–mass spectrometry (GC-MS) analysis revealed that oleic acid (OA) is a key antimicrobial compound produced by Pediococcus sp. M21F004. In vitro assays showed that the culture broth (CB) of Pediococcus sp. M21F004, as well as OA, exhibited significant inhibitory effects against pathogens such as Fusarium oxysporum, Clarireedia homoeocarpa, and Pectobacterium carotovorum subsp. carotovorum. In vivo tests on cucumber Fusarium wilt, creeping bentgrass dollar spot, tomato bacterial wilt, and kimchi cabbage soft rot further demonstrated the strain’s efficacy in reducing disease severity. Moreover, OA had the highest control value of 74% against tomato bacterial wilt, followed by 64.1% against cucumber fusarium wilt, 42.5% against kimchi cabbage soft rot, and 16.5% against creeping bentgrass dollar spot. These findings suggest that Pediococcus sp. M21F004 and its metabolite OA offer promising alternatives to chemical pesticides, contributing to sustainable plant disease management by promoting resistance induction and providing an eco-friendly approach to agriculture. Full article

Background: Inflammatory bowel disease (IBD) is a chronic condition characterized by recurrent episodes and an unclear etiology. Given the limitations of current therapeutic options, which include suboptimal efficacy and significant side effects, there is a pressing need to explore novel treatments. Probiotics derived from diverse species have been identified as a promising approach for managing IBD, owing to their anti-inflammatory properties and their ability to regulate gut flora, among other beneficial effects. Methods: In this study, three strains of lactic acid bacteria (LAB) were isolated from the feces of the scavenger spotted hyena (Crocuta crocuta), a scavenging mammal. Based on their capability to survive within and adhere to the gastrointestinal tract, along with their profile of antibiotic resistance, a high-quality strain of Lactobacillus acidophilus (LA) was selected and demonstrated to be safe for mice. Subsequently, the therapeutic efficacy of LA was evaluated using a dextran sulfate sodium (DSS)-induced model of ulcerative colitis in mice. Results: The results indicated that LA restored the disease activity index and improved histopathological lesions in the model group. It also reduced inflammation and oxidative stress and significantly restored the expression of mucins and intestinal tight junction (TJ) proteins (ZO-1, Occludin). Furthermore, LA corrected the DSS-induced disruption of the intestinal flora, leading to a significant decrease in the prevalence of potentially harmful bacterial genera, such as Bacteroides, and an increase in beneficial bacterial genera, including Lactobacillus. In conclusion, Lactobacillus acidophilus LA1, isolated from spotted hyena feces, has potential as a functional supplement for alleviating symptoms of IBD and regulating intestinal flora. Full article

The food industry constantly seeks new starter cultures with superior characteristics to enhance the sensory and overall quality of final products. Starting from a collection of Algerian dairy (goat and camel) lactic acid bacteria, this work focused on the exploration of the technological and probiotic potential of Weissella cibaria (VR81 and LVT1) and Lactiplantibacillus plantarum R12 strains isolated from raw camel milk and fermented milk, respectively. These bioactive strains were selected for their high performance among ten other LAB strains and were used as starter cultures to develop a novel and nutritionally enhanced dairy-like plant-based yogurt using quinoa (Chenopodium quinoa Willd) as a raw matrix. The strains were evaluated for their antagonistic effects against Listeria innocua, Listeria ivanovii, Staphylococcus aureus, Escherichia coli, Salmonella enterica, and Pseudomonas aeruginosa, resilience to acidic and osmotic challenges, and tolerance to gastrointestinal mimicking conditions (i.e., pepsin and bile salt). Their aggregation and adhesion profiles were also analyzed. Furthermore, L. plantarum and W. cibaria were tested in single and co-culture for the fermentation and biocontrol of quinoa. The strains exhibited probiotic properties, including a high potential for biocontrol applications, specifically against L. innocua and P. aeruginosa (20 mm diameter zone with the neutralized cell-free supernatant), which disappeared after protease treatment, suggesting that bioactive peptides might be responsible for the observed antimicrobial effect. Additionally, they demonstrated resilience to acidic (pH 2) and osmotic challenges (1M sucrose), tolerance to gastro-intestinal conditions, as well as good aggregation and adhesion profile. Furthermore, the strains were able to produce metabolites of interest, such as exopolysaccharide (yielding up to 4.7 mg/mL) and riboflavin, reaching considerable production levels of 2.5 mg/L upon roseoflavin selection. The application of W. cibaria and L. plantarum as primary starters (both in single and co-culture) for fermenting quinoa resulted in effective acidification of the matrix (ΔpH of 2.03 units) and high-quality beverage production. in vivo challenge tests against L. innocua showed the complete inhibition of this pathogen when L. plantarum was included in the starter, either alone or in combination with W. cibaria. Both species also inhibited Staphylococcus and filamentous fungi. Moreover, the co-culture of mutant strains of L. plantarum R12d and W. cibaria VR81d produced riboflavin levels of 175.41 µg/100 g in fermented quinoa, underscoring their potential as starters for the fermentation, biopreservation, and biofortification of quinoa while also displaying promising probiotic characteristics. Full article