Recent advances in the biological activities of microbial exopolysaccharides

Abstract

Microbial exopolysaccharides (EPSs) are valuable extracellular macromolecules secreted as capsules or slime layers. Various microorganisms, including bacteria, yeasts, fungi, and algae have been studied for their ability to produce EPSs. Microbial EPSs exist as homopolysaccharides or heteropolysaccharides with various properties such as different monosaccharide compositions, structural conformation, molecular weight, and functional groups. They are cost-effective alternatives to plant and animal-derived polysaccharides because the microbial cells produced them in large quantities by biotechnological processes using low-cost substrates such as industrial wastes in a short time. Microbial EPSs are safe, biodegradable, and compatible polymers. They have extensive bioactivities, including antibacterial, antifungal, antiviral, antioxidant, antitumor, antidiabetic, antiulcer, anticoagulant, antiaging, immunomodulatory, wound healing, and cholesterol-lowering activities. Microbial EPSs owing to biological activities, special biochemical structures, and attractive physicochemical properties find plenty of potential applications in various industries. The enhancement of the production of EPSs and improving their properties can be provided by genetic engineering methods. The current review aims to provide a comprehensive examination of the therapeutic activities of microbial EPSs in infectious diseases and metabolic disorders, with a focus on the mechanisms involved. Also, the effect of the physicochemical characteristics of EPSs on these bioactivities was discussed to reveal the structure-activity relationship.

Bifidobacterium exopolysaccharides: new insights into engineering strategies, physicochemical functions, and immunomodulatory effects on host health

“…EPS can be categorized into two groups based on their properties, namely homopolysaccharides (HoPSs), composed of a single monosaccharide, and heteropolysaccharides (HePSs), consisting of one or more types of monosaccharides ( Salazar et al, 2016 ; Angelin and Kavitha, 2020 ; Netrusov et al, 2023 ; Salimi and Farrokh, 2023 ). While homopolysaccharides are produced by certain lactic acid bacteria, their production in bifidobacteria remains unidentified ( Hidalgo-Cantabrana et al, 2012 ; Castro-Bravo et al, 2018b ; Lynch et al, 2018 ).…”

“…Additionally, housekeeping genes involved in sugar nucleotide formation play a crucial role. Given the abundance of the CRISPR-Cas system in bifidobacteria, gene editing using the CRISPR system offers a promising avenue for modifying EPS with new biological activities ( Xu et al, 2019 ; Zuo et al, 2020 ; Sun and Zhang, 2021 ; Salimi and Farrokh, 2023 ).…”

The Crucial Roles of Diet, Microbiota, and Postbiotics in Colorectal Cancer

“…EPSs are homopolysaccharides or heteropolysaccharides with different properties in terms of their composition, structural conformation, molecular weight, and functional groups. Microbial EPSs are more cost-effective than polysaccharides of plant and animal origin, and large amounts of EPS can be produced in a short time using low-cost substrates such as microorganism wastes [ 120 ].…”

Postbiotics: Functional Food Materials and Therapeutic Agents for Cancer, Diabetes, and Inflammatory Diseases

“…Folic acid functions as an antioxidant by lowering the production of superoxide radicals catalyzed by nitric oxide synthase (NOS) [ 234 ].EPSs from Bacillus subtilis sp. suppress (BSEPS) control hyperglycemia and dyslipidemia in diabetic rats by increasing insulin levels and decreasing blood glucose and troponin blood concentrations [ 235 ].The fact that EPSs from Lactobacillus plantarum H31-2 decreased the amount of glucose in the supernatant of insulin-resistant HepG2 cells suggests that EPS H31-2 may help these cells to take up glucose through the AMPK/PI3K/Akt pathway. The expression of the glycometabolism-related genes glucose transporter 4 (GLUT-4), protein kinase B (Akt-2), and AMP-activated kinase (AMPK) was also elevated by EPS H31-2.…”