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In this study, 22 strains of exopolysaccharides-producing lactic acid bacteria were isolated from silage, and the strain SSC–12 with the highest exopolysaccharide (EPS) production was used as the test strain. The SSC–12 was identified as Pediococcus pentosaceus, based upon 16S rDNA gene sequencing and Neighbor Joining (NJ) phylogenetic analysis. The analysis of the kinetic results of EPS generation of SSC–12 showed that the EPS generation reached the maximum value at 20 h of culture. The characterization study showed the EPS produced by SSC–12 was a homogeneous heteropolysaccharide comprising glucose (42.6%), mannose (28.9%), galactose (16.2%), arabinose (9.4%), and rhamnose (2.9%). The EPS had good antioxidant activity, especially the activity of scavenging hydroxyl free radicals. At the same time, the EPS also had strong antibacterial ability and could completely inhibit the growth of Staphylococcus aureus. The EPS produced by the Pediococcus pentosaceus SSC–12 can be used as a biologically active product with potential application prospects in the feed, food, and pharmaceutical industries.

Fungal β-glucans are naturally occurring active macromolecules used in food and medicine due to their wide range of biological activities and positive health benefits. Significant research efforts have been devoted over the past decade to producing fungal β-glucan-based nanomaterials and promoting their uses in numerous fields, including biomedicine. Herein, this review offers an up-to-date report on the synthetic strategies of common fungal β-glucan-based nanomaterials and preparation methods such as nanoprecipitation and emulsification. In addition, we highlight current examples of fungal β-glucan-based theranostic nanosystems and their prospective use for drug delivery and treatment in anti-cancer, vaccination, as well as anti-inflammatory treatments. It is anticipated that future advances in polysaccharide chemistry and nanotechnology will aid in the clinical translation of fungal β-glucan-based nanomaterials for the delivery of drugs and the treatment of illnesses.

β-d-glucans have the potential of serving as both macrophage-targeted carriers and immune stimulators via inducing trained immunity in macrophages. In this study, a carboxymethylated β-glucan from mushroom sclerotium of Pleurotus tuber-regium (CMPTR) was combined with iron oxide nanoparticles (IONPs) to form nanocomplexes (CMPTR/IONPs) with particle size around 193 ± 7 nm, which could exert a concerted effect on inducing proinflammatory M1 phenotype macrophages for immunotherapy. This nanocomplex exhibited good stability and low cytotoxicity (over 80% cellular viability of RAW 264.7 and THP-1) and higher cellular uptake by murine macrophages compared with B16F10 cells (p < 0.05). CMPTR/IONPs could convert M2-like bone marrow-derived macrophages into M1 phenotypes with upregulated expression of pro-inflammatory cytokines (IL12 and TNF-α, p < 0.05) and reduced immune-suppressive cytokines (IL10 and TGF-β, p < 0.05). Such polarization was mediated by the combined signaling regulatory factors, including IONP-stimulated IRF5 and CMPTR-triggered TLRs-NF-κB pathways (p < 0.05). Accordingly, CMPTR could have a dual function as a macrophage-targeting carrier for IONPs and an immunostimulant to induce inflammatory M1 macrophage polarization for immunotherapy.

Background: The exopolysaccharides (EPS) produced by lactic acid bacteria (LAB) are widely used in various fields because of their safety and various biological activities. In this study, we extracted and characterized the composition as well as antioxidant and antibacterial activities of EPS from Pediococcus pentosaceus SSC-12 isolated from the silage.Results: The LAB strain SSC-12 was screened and identified as Pediococcus pentosaceus, based upon 16S rDNA gene sequencing and Neighbor Joining (NJ) phylogenetic analysis. The analysis of the EPS production kinetics results of SSC-12 showed that the EPS production reached the maximum at 20 h of culture. High-performance anion exchange chromatography (HPAEC) analysis showed that the EPS produced by SSC-12 was a heteropolysaccharide comprising glucose (42.6 %), mannose (28.9 %), galactose (16.2 %), arabinose (9.4 %) and rhamnose (2.9 %). The EPS had good antioxidant activity, especially hydroxyl radical scavenging activity. When the concentration of the EPS produced by SSC-12 (SSC-12 EPS) was 10 mg/mL, its 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging ability, hydroxyl radical scavenging ability, superoxide scavenging ability, and reduction ability were 77.4 %, 97.5 %, 77.5 % and 1.3, respectively. At 10 mg/mL，SSC-12 EPS completely killed Staphylococcus aureus GDMCC 1.1220 and substantially inhibited the growth of Salmonella enterica subsp. enterica GDMCC 1.345; however, it had a weak inhibitory effect on Listeria monocytogenes GDMCC 1.347. Conclusions: Due to its strong antioxidant and antibacterial properties, EPS produced by LAB strain SSC-12 have potential application as a bioactive product in the feed, food, and pharmaceutical industries.