Digestive characteristics of extracellular polysaccharide from Lactiplantibacillus plantarum T1 and its regulation of intestinal microbiota.

This study assessed the potential prebiotic characteristics of the previously reported Lactiplantibacillus plantarum extracellular polysaccharide (EPS-T1) with immunological activity. EPS-T1 was a novel heteropolysaccharide composed of glucose and galactose (1.00:1.21), with a molecular weight of 1.41 × 106 Da. The monosaccharide composition, molecular weight, fourier transform infrared, and 1H NMR analysis showed that EPS-T1 was well tolerated in the simulated oral cavity, gastric fluid, and small intestinal fluid environments, and was not easily degraded. Meanwhile, EPS-T1 could effectively be used as a carbon source to promote the growth of beneficial Lactobacillus species (Lactobacillus delbrueckii ssp. Bulgaricus, Streptococcus thermophilus, Lacticaseibacillus rhamnose GG, Lactiplantibacillus plantarum, Lacticaseibacillus paracasei and Lactobacillus reuteri). After 24 h of fecal fermentation, EPS-T1(5 mg/mL) effectively reduced the relative abundance of harmful bacteria such as the Escherichia-Shigella, Citrobacter, Fusobacterium, Parasutterella, and Lachnoclostridium. While, the level content of beneficial flora (Bacteroides, Blautia, Phascolarctobacterium, Bifidobacterium, Parabacteroides, and Subdoligranulum) were significantly increased. In addition, EPS-T1 was able to significantly promote the enrichment of short-chain fatty acids such as acetic acid, propionic acid and butyric acid. These results provide some basis for the functional application of EPS-T1 as a potential prebiotic.

Effects of Lacticaseibacillus paracasei SNB-derived postbiotic components on intestinal barrier dysfunction and composition of gut microbiota.

The bacterial surface components are considered as effector molecules and show the potential to support intestinal health, but the detailed mechanism of how the gut microbiota changes after the intervention of surface molecules is still unknown. In the present study, capsular polysaccharide (B-CPS) and surface layer protein (B-SLP) were extracted from Lacticaseibacillus paracasei S-NB. The protective effect of direct administration of B-CPS (100 µg/mL) and B-SLP (100 µg/mL) on intestinal epithelial barrier dysfunction was verified based on the LPS-induced Caco-2 cell model. Additionally, the B-CPS and B-SLP could be utilized as carbon source and nitrogen source for the growth of several Lactobacillus strains, respectively. The postbiotic potential of B-CPS and B-SLP was further evaluated by in vitro fermentation with fecal cultures. The B-CPS and a combination of B-CPS and B-SLP regulated the composition of gut microbiota by increasing the relative abundances of Bacteroides, Bifidobacterium, Phascolarctobacterium, Parabacteroides, Subdoligranulum and Collinsella and decreasing the abundance of pathogenic bacteria like Escherichia-Shigella, Blautia, Citrobacter and Fusobacterium. Meanwhile, the total short-chain fatty acid production markedly increased after fermentation with either B-CPS individually or in combination with B-SLP. These results provided an important basis for the application of B-CPS and B-SLP as postbiotics to improve human intestinal health.

Protective effect of Paecilomyces cicadae TJJ11213 exopolysaccharide on intestinal mucosa and regulation of gut microbiota in immunosuppressed mice.

The exopolysaccharide (EPS) form Paecilomyces cicadae TJJ1213 possessed immunomodulatory activity in vitro, but whether it could regulate the immune system and intestinal microbiota in vivo remained unknown. In this study, the cyclophosphamide (CTX)-induced immunosuppressive mouse model was established to explore the immunomodulatory activity of EPS. Results showed that EPS could increase the immune organ indices, promote the secretion of serum immunoglobulins and up-regulate the expression of cytokines. Additionally, EPS could repair CTX-induced intestinal injury by increasing the expression of tight junction proteins and promoting the production of short-chain fatty acids. Moreover, EPS could remarkably enhance immunity through TLR4/MyD88/NF-κB and mitogen-activated protein kinase (MAPK) signaling pathways. Furthermore, EPS regulated intestinal microbiota by increasing the abundance of beneficial bacteria (Muribaculaceae, Lachnospiraceae NK4A136, Bacteroides, Odoribacter) and reducing the level of harmful bacteria (Alistipes, Helicobacter). In conclusion, our study suggested that EPS had the abilities to enhance immunity, restore intestinal mucosal injury and modulate intestinal microbiota, and may serve as a potential prebiotic to maintain health in the future.

Comparative analysis of exopolysaccharide-producing Lactiplantibacillus plantarum with ropy and non-ropy phenotypes on the gel properties and protein conformation of fermented milk.

In this study, we evaluated the impact of Lactiplantibacillus plantarum (L. plantarum) with ropy and non-ropy phenotypes on gel structure and protein conformation of fermented milk. Ropy L. plantarum (T1 & CL80) secreted EPS with high molecular weight (1.41 × 106, 1.19 × 106 Da) and intrinsic viscosity (486.46, 316.32 mL/g), effectively enhances fermented milk viscosity and water holding capacity (WHC) (65.4%, 84.6%) by forming a dense gel structure. Non-ropy L. plantarum (CSK & S-1A) fermented milk gel's high surface hydrophobicity and free sulfhydryl content caused high hardness and low WHC. Raman spectroscopy combined with circular dichroism analysis showed that high levels of α-helix (29.32-30.31%) and random roil (23.06-25.36%) protein structures are the intrinsic factors that contribute to the difference among fermented milk gels of ropy and non-ropy strains. This study provides a basis for understanding the structural variability of fermented milk gels using ropy or non-ropy lactic acid bacteria.

Controlled release of Lactiplantibacillus plantarum by colon-targeted adhesive pectin microspheres: Effects of pectin methyl esterification degrees.

The aim of this study is to report the preparation of pectin microspheres by varying degrees of methyl esterification (DM) cross-linked with divalent cationic calcium to encapsulate Lactiplantibacillus plantarum STB1 and L. plantarum LJ1, respectively. Scanning electron microscopy revealed the compact and smooth surface of pectin of DM 28 %, and the stochastic distribution of L. plantarum throughout the gel reticulation. And the pectin of DM 28 % considerably increased probiotics tolerance after continuous exposure to stimulated gastrointestinal tract conditions, with viable counts exceeding 109 CFU/mL. This data indicated that low methoxy-esterification pectin was more efficient to improve the targeted delivery of probiotics in GIT. Additionally, the controlled release of microspheres was dependent on various pH levels. At pH 7.4, the release rates of L. plantarum STB1 and L. plantarum LJ1 reached up to 97.63 % and 95.33 %, respectively. Finally, the Caco-2 cell adhesion model was used to evaluate the cell adhesion rate after encapsulation, which exhibited better adhesion at DM of 60 %.

Prebiotic Properties of Exopolysaccharides from Lactobacillus helveticus LZ-R-5 and L. pentosus LZ-R-17 Evaluated by In Vitro Simulated Digestion and Fermentation.

The in vitro digestion and fermentation behaviors of Lactobacillus helveticus LZ-R-5- and L. pentosus LZ-R-17-sourced exopolysaccharides (LHEPS and LPEPS) were investigated by stimulated batch-culture fermentation system. The results illustrated that LHEPS was resistant to simulated saliva and gastrointestinal (GSI) digestion, whereas LPEPS generated a few monosaccharides after digestion without significant influence on its main structure. Additionally, LHEPS and LPEPS could be consumed by the human gut microbiota and presented stronger bifidogenic effect comparing to α-glucan and ß-glucan, as they promote the proliferation of Lactobacillus and Bifidobacterium in cultures and exhibited high values of selectivity index (13.88 and 11.78, respectively). Furthermore, LPEPS achieved higher contents of lactic acid and acetic acid (35.74 mM and 45.91 mM, respectively) than LHEPS (35.20 mM and 44.65 mM, respectively) during fermentation for 48 h, thus also resulting in a larger amount of total SCFAs (110.86 mM). These results have clearly indicated the potential prebiotic property of EPS fractions from L. helveticus LZ-R-5 and L. pentosus LZ-R-17, which could be further developed as new functional food prebiotics to beneficially improve human gut health.