Search Results (525)

Postbiotics—defined by the International Scientific Association of Probiotics and Prebiotics (ISAPP) as preparations of inanimate microorganisms and/or their components that confer a health benefit to the host—are attractive from a stability perspective compared to live probiotics. They withstand thermal processing and room-temperature transport and storage and are compatible with low-pH or low-water-activity food products. Despite the promise, the literature is scattered, with no review that integrates evidence from the development pipeline. This review fills that gap. The ISAPP 2021 definition is reviewed, including the practical difficulty resulting from the exclusion of cell-free supernatant (CFS)-based products that represent most of the experimental evidence. Fermentation-based production systems and non-thermal inactivation technologies—high-pressure processing (HPP), pulsed electric fields (PEF), ultrasound, cold plasma, and supercritical CO₂—are compared; non-thermal inactivation preserves the activity of thermolabile bacteriocins and phenolic fractions. Delivery systems such as spray-drying, alginate hydrogel microencapsulation, liposomal nanoencapsulation, and carboxymethyl cellulose (CMC) active packaging are assessed for gastrointestinal survival and food system compatibility. Biopreservation potential is reviewed in meat, seafood, dairy, fresh produce, and fermented foods. The regulatory framework for the United States, European Union, Japan, and India is critically reviewed; “postbiotic” is not an explicitly defined term in 2025. Three priority translational bottlenecks are identified: the absence of standardized potency assays, the lack of cross-class quality benchmarks, and the unresolved conflict between heat-inactivated dairy postbiotics and the Codex Alimentarius live-culture standard. Harmonized regulations and characterization standards are critical needs for postbiotic functional food development. Full article

Black spot disease caused by Ceratocystis fimbriata (C. fimbriata) is a severe postharvest disease of sweet potatoes. This study evaluated the biocontrol potential of Bacillus velezensis (B. velezensis) L33a against this pathogen. Confrontation assays showed that L33a inhibited mycelial growth by 82.83%. FDA/PI staining and scanning electron microscopy revealed that L33a disrupted cell membrane integrity and caused severe mycelial deformation. Co-culture experiments indicated that L33a altered the expression of key pathogenic genes in C. fimbriata. Volatile organic compounds (VOCs) from L33a inhibited the pathogen by 77.78%, outperforming cell-free supernatant (CFS). VOCs primarily suppressed spore germination, with phenylethanol (PEA) and octanoic acid achieving 100% inhibition. In planta tests on sweet potato tubers showed that both L33a culture and VOCs significantly reduced lesion expansion. Using qPCR analysis, we found that L33a activated defense-related genes in tissues around wounds, particularly those involved in the jasmonic acid (JA) signaling pathway. In summary, B. velezensis L33a effectively controls sweet potato black rot through multiple mechanisms: direct antifungal activity, inhibition of spore germination, modulation of pathogen gene expression, and induction of host defense responses. It represents a promising natural inhibitor for postharvest disease management. Full article

Potato dry rot, induced by pathogenic Fusarium species, is a prevalent postharvest fungal disease that leads to significant economic losses. This research illustrates the biocontrol efficacy of Bacillus velezensis strain 2-1-9-CJK-2 against potato dry rot. The strain successfully inhibited disease progression, diminished oxidative damage in potato tubers, and augmented the activity of essential defense-related enzymes. It effectively colonized potato tubers and sustained consistent inhibitory activity under diverse environmental challenges. And its cell-free supernatant (CFS) retained consistent inhibitory activity. The crude lipopeptides (CLs) produced by this strain induced hyphal deformation, fragmentation, and cytoplasmic leakage in Fusarium solani. Transmission electron microscopy (TEM) further revealed that CL treatments triggered organelle degradation in the pathogen, with mitochondrial disintegration being particularly prominent. Transcriptomic analysis indicated that CLs upregulated genes linked to mitochondrial autophagy in the pathogen and stimulated plant defense mechanisms, notably the MAPK signaling cascade, in potatoes. The findings were additionally corroborated by qRT-PCR. B. velezensis strain 2-1-9-CJK-2 is a promising biocontrol agent and a great resource for the development of antifungal formulations to enhance sustainable potato production. Full article

Acinetobacter baumannii, a multidrug-resistant pathogen of critical priority within the ESKAPE group, poses a significant threat to global healthcare, particularly in the context of nosocomial infections. Its pathogenesis is mediated not only by antibiotic resistance determinants but also by a complex repertoire of secreted virulence factors. However, comprehensive characterization of the A. baumannii secretome remains methodologically challenging due to spectral overlap in complex biological matrices. In this study, we applied a hybrid approach integrating size-exclusion chromatography with Raman spectroscopy to deconvolute the cell-free supernatant of A. baumannii. Chromatographic fractionation into seven fractions reduced spectral complexity and enabled the identification of unique metabolic profiles. Fraction 3 exhibited a distinct composition, containing specific markers for phosphatidylserine (~1724 cm⁻¹), cysteine, phosphatidylinositol, and DNA (~770–806 cm⁻¹), as well as CH₂ groups of lipids and amino acids (~1450–1456 cm⁻¹), while lacking signals corresponding to methionine-containing compounds, nucleic acid backbones, and polypeptide backbones characteristic of other fractions. Analysis revealed distinct biochemical specialization across fractions: Fraction 2 was enriched in glutamine/asparagine-associated signals (~990, ~998 cm⁻¹), Fraction 4 contained a unique carotenoid marker (~1154 cm⁻¹), Fraction 6 exhibited a phenylalanine-specific peak (~1104 cm⁻¹), and Fraction 7 demonstrated the highest intensity of cysteine-containing protein, nucleotide, and phospholipid signals. These findings open new avenues for the discovery of biomarkers associated with virulence and antibiotic resistance in A. baumannii. Full article

Six lactic acid bacteria isolated from São Jorge PDO cheese were characterised for technological, safety, antimicrobial, and probiotic properties. All isolates fermented a broad range of carbohydrates and lacked lipolytic activity, while SJC115 and SJC119 showed proteolysis. Safety profiling (γ-haemolysis, no DNase or gelatinase activity, and generally favourable antibiotic susceptibility) is promising, but tetracycline resistance warrants caution and genomic confirmation. L. paracasei and L. brevis isolates inhibited a wide range of foodborne pathogens (Listeria monocytogenes, Escherichia coli, Pseudomonas aeruginosa, Salmonella enterica, Bacillus spp.) and spoilage fungi (Penicillium and Aspergillus spp.). Notably, two isolates (SJC117 and SJC120) exhibited antibacterial activity in neutralized cell-free supernatants, indicating putative bacteriocin-like inhibitory substances (BLIS). The isolates survived intestinal conditions above the probiotic threshold, yet only SJC117 and SJC120 tolerated gastric acidity (pH 2.5, 1 h) with >5 log CFU/mL. Despite low hydrophobicity, strains showed good autoaggregation and pathogen coaggregation. All isolates produced exopolysaccharides (EPS) and angiotensin-converting enzyme (ACE) inhibitory peptides, whereas some exhibited moderate conjugated linoleic acid (CLA) production and glutamate decarboxylase (GAD) activity. L. paracasei SJC117 stood out by combining BLIS/antifungal activity, superior gastric tolerance, and an exceptional bioactive profile, making it a promising candidate for biopreservation and functional food applications that warrants further in vivo validation to confirm its efficacy and safety. Full article

This study comprehensively examines the whole-genome sequence and probiotic potential of Lacticaseibacillus paracasei RM081, a strain originally isolated from raw bovine milk. Whole-genome sequencing and in silico analyses provided a robust molecular basis for its functional traits. The L. paracasei RM081 genome harbors an extensive repertoire of carbohydrate-active enzymes, suggesting strong prebiotic utilization capabilities. Crucially, genomic mining identified key genetic determinants for postbiotic synthesis, including the potential to synthesize the anti-inflammatory metabolite 5-methoxytryptophan (5-MTP). Moreover, comprehensive safety evaluations confirmed the absence of transferable antimicrobial resistance genes, virulence factors, biogenic amine-producing genes, and plasmids, indicating a secure genomic architecture without horizontal gene transfer risks. These genomic predictions were further substantiated by valid in vitro phenotypic models. The strain exhibited strong tolerance to gastric acid, maintaining high viability at pH 3.5 and 2.5 after 4 h, and survived well at 0.1% bile salt concentration. Furthermore, L. paracasei RM081 demonstrated robust cell surface properties, with a high auto-aggregation rate (85.0 ± 0.7%), hydrophobicity (71.5 ± 2.4%), and 78.0 ± 4.8% adhesion to Caco-2 intestinal epithelial cells, supporting its potential for colonization. Regarding antioxidant capacity, the cell-free supernatant displayed the highest DPPH scavenging activity (37%), indicating the active secretion of antioxidative metabolites. Collectively, these findings establish L. paracasei RM081 as a highly promising, safe probiotic and postbiotic candidate with verified colonization potential and functional capabilities. Full article

Good canine gastrointestinal health depends on the suppression of enteric pathogens and maintenance of epithelial barrier integrity. Limosilactobacillus reuteri ATCC PTA 6127 (Lr6127) is a dog-derived probiotic, but evidence supporting its functional properties remains limited. Here, we evaluated the antimicrobial and epithelial-supportive effects of Lr6127 using a canine epithelial cell model. Cell-free supernatant (CFS) from Lr6127 significantly inhibited the growth of canine-relevant pathogens, including Enterotoxigenic Escherichia coli (52.0 ± 1.3%), Clostridium perfringens (54.0 ± 2.7%), and Salmonella enterica subsp. enterica serovar Typhimurium (48.6 ± 1.2%), compared with the medium control (p < 0.0001). Pathogen inhibition increased in a dose-dependent manner with increasing CFS concentration. Untargeted metabolomic analysis revealed enrichment of multiple antimicrobial-associated metabolites, indicating a multi-component profile consistent with pathogen suppression, with genomic analysis supporting the aromatic amino acid-derived metabolite findings. In addition, viable Lr6127 significantly reduced the epithelial adhesion of all the tested pathogens (p < 0.01). Beyond direct antimicrobial effects, Lr6127 CFS promoted epithelial wound healing at later time points, accompanied by the coordinated modulation of proteins associated with cytoskeletal remodeling and barrier repair. Collectively, these findings support the idea that Lr6127 is associated with antimicrobial and epithelial-related effects, highlighting its potential to contribute to epithelial function under controlled in vitro conditions. Full article

This study describes extracellular vesicles (EVs) isolated from the culture supernatant of a Kluyveromyces marxianus strain deriving from an artisanal sourdough. Previous work had clearly shown the probiotic properties of the yeast isolate and its antagonistic activities against clinical fluconazole-resistant Candida albicans strains. Characterization of the isolated EVs by nanotracking particle analysis showed they had a mean diameter of 157.7 nm. Proteomic characterization of the purified EVs identified a complex array of 100 proteins. Both C. albicans planktonic growth and biofilm formation were inhibited by K. marxianus EVs, as well as adhesion and invasion of Candida cells in the vaginal epithelial A-431 cells. In the same cell model, K. marxianus EVs exerted an immunomodulatory effect affecting the secretion of pro-inflammatory and anti-inflammatory cytokines. Further, the expression of C. albicans SAP2 and SAP6 genes, coding for two aspartyl proteases involved in the invasion and damage of the epithelial mucosa, was affected by the presence of the yeast EVs. Overall, the results of this study show that K. marxianus EVs retain, at least in part, the beneficial features of the live microorganism, representing a postbiotic cell-free alternative preparation potentially useful for the management of C. albicans vaginal infections. Full article

Elucidating the interactions among microbial communities in the Sichuan paocai fermentation system is of great significance for ensuring the safety and quality of paocai. In this study, the interaction between Bacillus subtilis Y61 and Weissella paramesenteroides (CWP) was preliminarily verified through the culture of CWP using the cell-free supernatant derived from Y61. Building on this, a transwell chamber was employed to spatially isolate the two bacteria. Combined with transcriptomic and metabolomic profiling, the underlying interaction mechanism was revealed. Weissella paramesenteroides (CWP) exhibited enhanced growth in the cell-free supernatant of Bacillus subtilis Y61, confirming a cross-feeding relationship between the two strains. In the transwell chamber, the promoting effect was most significant when Weissella paramesenteroides (CWP) was in the upper compartment and Bacillus subtilis Y61 in the lower compartment. Transcriptomic analysis showed that Weissella paramesenteroides (CWP) significantly upregulated genes involved in fatty acid synthesis and metabolism while downregulating those related to amino acid anabolism (p < 0.05). Metabolomic analysis further revealed that metabolites secreted by Bacillus subtilis Y61, including the key metabolites arginine and isovaleric acid, were markedly depleted during co-culture. Exogenous supplementation assays revealed that the combination of 0.1 g arginine and 2 mg isovaleric acid exhibited the strongest growth-promoting effect on Weissella paramesenteroides (CWP). Collectively, these results demonstrated that Bacillus subtilis Y61 promoted the growth of Weissella paramesenteroides (CWP) through cross-feeding via the extracellular secretion of the key metabolites arginine and isovaleric acid. Full article

The aim of this review is to provide a narrative analysis of the role of Lactobacillus acidophilus as an active modulating factor in the prevention and treatment of cancer and allergic diseases. The paper discusses the molecular, metabolic, and bionanotechnological mechanisms of Lactobacillus acidophilus’s anticancer and immunomodulatory effects, which define this probiotic as an essential component of modern natural and functional medicine. A narrative review of the scientific literature was conducted, mainly from 2019–2026, focusing on the results of in vitro studies and studies on preclinical in vivo models, which analyzed the effect of live L. acidophilus strains, tyndallized bacteria (paraprobiotics) and cell-free supernatant from L. acidophilus cultures on, among others, immune system signaling pathways, tissue cytokine profile, and the integrity of the gastrointestinal epithelial cell barrier (enterocytes). Results indicate that L. acidophilus exerts significant antiallergic, antiproliferative, and proapoptotic effects against many types of cancer. Among other aspects, the ability of L. acidophilus to stimulate the production of anticancer exopolysaccharides and short-chain fatty acids, which directly influence the functioning of immune cells, is covered. The article thoroughly explains the immunomodulatory effects of L. acidophilus and the ability of this probiotic to regulate cytokine profiles, which helps promote an anti-inflammatory environment crucial for maintaining intestinal homeostasis. The article also discusses the direct interaction of L. acidophilus with immune cells, such as dendritic cells and macrophages, which leads to their activation and subsequent influence on the differentiation of T lymphocytes, which play a key role in the regulation of immune processes and in the development of immune tolerance. L. acidophilus is a universal mediator of immunological and metabolic homeostasis. Its ability to synergize with conventional therapies (chemotherapy, oncolytic virotherapy) and its innovative applications in the creation of postbiotics and paraprobiotics may provide a new approach to the treatment of inflammatory, allergic, and neoplastic diseases. Further clinical studies are necessary to assess the efficacy, safety, and optimal dose of this probiotic, which are essential for the widespread use of L. acidophilus in human therapy. Full article

Coordinated responses of intestinal epithelial and immune cells are essential for maintaining barrier integrity and immune homeostasis in dogs, yet our mechanistic understanding of probiotic-derived metabolites remains limited due to reliance on non-canine experimental models, highlighting the need for studies in canine-derived systems. Here, we investigated the effects of metabolites derived from Limosilactobacillus reuteri strain ATCC PTA6127 (Lr6127), delivered as a cell-free supernatant (CFS), on canine epithelial MCA-B1 cells and macrophage-like DH82 cells subjected to lipopolysaccharide (LPS)-induced inflammatory stress. Lr6127 CFS significantly reduced epithelial permeability, decreasing FITC–dextran leakage to 94.9 ± 1.9% (normalized relative to LPS-treated control, which was set as 100%) (p < 0.001), despite no detectable transcriptional changes in tight junction, adherens junction, or mucin genes. Barrier effects were instead associated with changes in markers of cellular stress responses, with heme oxygenase expression decreasing from 0.9 ± 0.1 to 0.7 ± 0.1 (p < 0.05). In DH82 immune cells, Lr6127-derived metabolites altered LPS-induced stress- and inflammation-related gene expression patterns; enhanced anti-apoptotic responses, as reflected by the increased BCL2 expression (1.4 ± 0.1 vs. 1.0 ± 0.0; p < 0.01) and elevated BCL2/BAX ratios (p < 0.01); and reduced expression of pro-inflammatory mediators including IL-6 and CCL2 (p < 0.05–0.001). Proteomic analysis corroborated that Lr6127-derived metabolites reduced the abundance of inflammatory and STAT-associated signaling proteins under LPS challenge, while indicating context-dependent changes in immune-related protein profiles under resting condition. Collectively, these results suggest that Lr6127-derived metabolites improved epithelial barrier function, which was accompanied by coordinated changes in cellular stress-related and inflammatory pathways, highlighting their potential to positively influence host responses. Full article

Naturally fermented tofu whey is a nutrient-rich byproduct of tofu production that harbors diverse lactic acid bacteria (LAB) with potential probiotic properties. However, the antioxidant mechanisms of these LAB, particularly the roles of different cellular fractions and their metabolic basis, remain unclear. This study aimed to isolate LAB from naturally fermented tofu whey and evaluate their antioxidant activities across cellular fractions, combining in vitro assays, 16S rDNA-based identification, metabolomic profiling, and cellular validation to elucidate the underlying mechanisms. Six LAB strains were isolated and screened for 2,2-diphenyl-1-picrylhydrazyl and hydroxyl radical scavenging capacity and environmental stress tolerance. Among the identified isolates, Lactiplantibacillus plantarum MCS1903 exhibited the highest extracellular antioxidant activity. Non-targeted metabolomic analysis of cell-free supernatant revealed distinct metabolic profiles compared with the MRS control, with significant enrichment of antioxidant-related metabolites and pathways. In Caco-2 cells, MCS1903 supernatant (<5%, v/v) showed no significant cytotoxicity and effectively alleviated H₂O₂-induced oxidative stress by modulating the Nrf2/Keap1-HO-1 signaling pathway. These findings indicate that tofu whey is a valuable source of functional LAB, and MCS1903 represents a promising candidate for probiotic and functional food applications, supporting the valorization of tofu whey and development of natural antioxidant probiotics derived from fermented food byproducts. Full article

Biosurfactants are surface-active microbial molecules with increasing industrial relevance as sustainable alternatives to synthetic surfactants. Among them, lipopeptides produced by Bacillus species, particularly surfactin, exhibit strong interfacial activity and biological functionality. In this study, rhizospheric soils from the La Araucanía region, Chile, were explored as a source of biosurfactant-producing bacteria. Eighteen strains were isolated, and two high-performing strains, Solo 1 and Solo 4, were identified as Bacillus amyloliquefaciens and Bacillus subtilis, respectively. Both strains harbored the srfAA gene and produced surfactin isoforms confirmed by MALDI-TOF MS. Kinetic analysis revealed distinct production profiles, with Solo 1 reaching a maximum of 90 mg L⁻¹ at 24 h, whereas Solo 4 showed continuous production up to 224.4 mg L⁻¹ at 72 h. Both biosurfactants exhibited high emulsification capacity (>80%) and stability across wide ranges of temperature, pH, and salinity. Importantly, cell-free supernatants from both strains showed antibacterial and antibiofilm activity against Staphylococcus aureus, with Solo 4 reaching 81% biofilm inhibition. In addition, surfactin-enriched extracts inhibited the pathogenic bacterium Pseudomonas syringae and the filamentous fungus Fusarium oxysporum, with Solo 4 consistently showing stronger antimicrobial performance. Overall, these findings identify Solo 4 as a promising native Bacillus strain for future development of biosurfactant-based systems aimed at antimicrobial control, biofilm management, agricultural pathogen suppression, surface sanitation, and environmentally compatible biotechnological processes. Full article

Lactic acid bacteria (LAB) have been widely utilized in the production of fermented foods worldwide due to their well-established health-promoting benefits for both humans and animals. In addition to their nutritional value, LAB exhibit antagonistic activity against foodborne pathogens, particularly Salmonella spp., which are commonly associated with livestock and animal production systems. LAB exert a range of biological effects that can inhibit the growth of Salmonella and modulate its virulence. In the present study, the antagonistic potential of Weissella confusa WM36 was evaluated based on its ability to inhibit S. Typhimurium growth, disrupt biofilm formation, and suppress the expression of virulence-associated genes. A preliminary safety assessment of W. confusa WM36 was conducted through hemolytic activity and antibiotic susceptibility profiling. In addition, the biofunctional properties of its cell-free supernatant (CFS), herein referred to as postbiotic metabolites, were investigated with a particular focus on antioxidant activity. Experimental results demonstrated that W. confusa WM36 and its CFS at 40% (v/v) achieved a complete reduction (100%) of S. Typhimurium cell counts within 6 to 12 h of treatment. Furthermore, CFS at 20% and 40% (v/v) significantly impaired biofilm formation, while treatment with 20% (v/v) CFS markedly downregulated the expression of key virulence genes. The strain WM36 exhibited α-hemolytic activity and showed susceptibility to most of the antibiotics tested, although resistance to ceftriaxone and trimethoprim–sulfamethoxazole was observed. These findings provide preliminary information regarding its safety characteristics; however, further molecular and in vivo investigations are required to comprehensively evaluate its safety for practical applications. Additionally, the CFS exhibited notable antioxidant activity, with DPPH radical scavenging capacity of 8.90 ± 0.06 mM Trolox equivalents and ABTS radical scavenging power of 13.10 ± 1.42 mM Trolox equivalents. Collectively, these findings highlight the potential of W. confusa WM36 and its postbiotic metabolites as promising biocontrol and functional agents against S. Typhimurium, while further safety validation remains necessary. Full article

Background: Postbiotics, including cell-free supernatants and their fractions, have emerged as a safe and effective alternative to live probiotics for managing intestinal inflammation. This study investigated the protective effects of low-molecular-weight fractions (<3 kDa) of the probiotic Limosilactobacillus fermentum CECT5716 (LMW-LF) in a murine model of experimental colitis. Methods: Male C57BL/6J mice were orally administered LMW-LF for 10 days prior to colitis induction with 3% dextran sodium sulfate (DSS) for 5 days. Colonic damage was assessed via the Disease Activity Index (DAI), histology, and immunofluorescence (Ocln and Ki67). Immune cell populations were analyzed by flow cytometry, while mucosal gene expression and gut microbiota composition were evaluated using RT-qPCR and 16S rRNA sequencing, respectively. Results: LMW-LF administration significantly attenuated clinical symptoms and macroscopic colonic damage. Treatment restored epithelial barrier integrity by upregulating tight junction proteins (Tjp1) and mucin genes (Muc1-3) while normalizing DSS-induced epithelial hyperproliferation. Immunologically, LMW-LF reduced pro-inflammatory monocyte infiltration; downregulated Il6, Tnfa, and Ifng; and promoted an immunoregulatory phenotype by enhancing Ampk expression and partially restoring regulatory T cell (Treg) populations. Furthermore, LMW-LF reshaped the gut microbiota by increasing alpha diversity and promoting the enrichment of beneficial taxa, specifically Akkermansia muciniphila, which correlated with improved mucus layer preservation. Conclusions: LMW-LF is an active fraction acting across the host–microbiota axis. By integrating epithelial protection, immunomodulation, and microbial reshaping, it represents a promising dietary strategy for the management of Inflammatory Bowel Diseases. Full article