Exopolysaccharides of Potential Probiotic Bacteria Bacillus subtilis BB2: Characterization, Antioxidant and Antibiofilm Activities

Microbial exopolysaccharides (EPS) may have technological applications in food and pharmaceutical industries, and in environmental health. EPS may be used in foods as natural thickening, stabilizing, bodying or gelling agent, and/or as emulsifiers or as fat replacer. In addition, EPS has been reported to have health augmenting features such as prebiotic, immunostimulatory, anti-tumor and hypocholesterolemic properties. EPS producing probiotics bacteria may help enhancing organoleptic properties of fermented foods. In present study, Enterococcus faecium strains viz. Enterococcus faecium 1.1, E. faecium 2.0 and E. faecium 4.0, which had several probiotically important attributes, were investigated for their EPS producing potential. E. faecium 4.0 produced highest yield of EPS (470 mg/L) and was followed by E. faecium 1.1 (220 mg/L) and E. faecium 2.0 (180 mg/L). FTIR analysis showed that EPS from all the three E. faecium strains was homopolymer of glucose. Degradation temperatures of EPS from three E. faecium strains varied in the range of 270.4°C-279.3°C as studied by thermal gravimetric analysis. Differential scanning calorimetry of EPS from E. faecium 1.1, E. faecium 2.0 and E. faecium 4.0 showed the melting point of 55.9°C, 88.6°C and 83.5°C; and enthalpy of 102.5, 56.03, and 213.9 J/g, respectively. EPS from all the three E. faecium strains expressed growth inhibition of E. coli. Purified EPS from all three E. faecium strains exhibited excellent emulsification properties i.e. 96.70 % (E. faecium 1.1), 96.78 % (E. faecium 2.0) and 97.77 % (E. faecium 4.0). Keywords: Enterococcus faecium, exopolysaccharide, FTIR, emulsifying activity.

Chapter 22 - Bioconversion of Whey Lactose into Microbial Exopolysaccharides

EDITORIAL article Front. Microbiol., 11 March 2016Sec. Microbiotechnology Volume 7 - 2016 | https://doi.org/10.3389/fmicb.2016.00308

Overview of exopolysaccharides produced by Weissella genus – A review

Purification and structural-functional characterization of an exopolysaccharide from Bacillus licheniformis PASS26 with in-vitro antitumor and wound healing activities

Antipathogenic potentials of exopolysaccharides produced by lactic acid bacteria and their food and health applications

Production of exopolysaccharides (EPSs) has been reported in prokaryotes and eukaryotes. Microbial exopolysaccharides have increased interest as another category of microbial products utilized in the pharmaceutical, biomedical, and food industries. Investigators are considering replacing synthetic food stabilizers with organic ones by investigating EPS in fermentation-based dairy industries. Particularly for the enhancement of the rheology of fermented food items, EPS is being used. EPSs are considered a natural texturizer and a good alternative for other artificial or new biopolymers utilized in foodstuff as a gelling agent and for suspending and thickening food. These EPS are used abundantly in fermented food and dairy industrials for quality improvement. The main microbial exopolysaccharides viz. dextran, xanthan, pullulan, gellan, curdlan, and scleroglucan have a versatile reputation and various food processing applications in industries. The review discusses the distinctive physical properties of EPSs that mainly determine their application in food industries and the health benefits of EPSs.

Exopolysaccharides (EPS) are extracellular sugar metabolites/polymers of some slim microorganisms and, a wide variety of probiotics have been broadly investigated for their ability to produce EPS. EPS originated from probiotics have potential applications in food, pharmaceutical, cosmetology, wastewater treatment, and textiles industries, nevertheless slight is recognized about their function. The present review purposes to comprehensively discuss the structure, classification, biosynthesis, extraction, purification, sources, health-promoting properties, techno-functional benefits, application in the food industry, safety, toxicology, analysis, and characterization methods of EPS originated from probiotic microorganisms. Various studies have shown that probiotic EPS used as stabilizers, emulsifiers, gelling agents, viscosifiers, and prebiotics can alter the nutritional, texture, and rheological characteristics of food and beverages and play a major role in improving the quality of these products. Numerous studies have also proven the beneficial health effects of probiotic EPS, including antioxidant, antimicrobial, anti-inflammatory, immunomodulatory, anticancer, antidiabetic, antibiofilm, antiulcer, and antitoxin activities. Although the use of probiotic EPS has health effects and improves the organoleptic and textural properties of food and pharmaceutical products and there is a high tendency for their use in related industries, the production yield of these products is low and requires basic studies to support their products in large scale.

Hydrocolloids: Structure, preparation method, and application in food industry

Exopolysaccharides (EPS) produced by bacteria are high molecular weight secondary metabolites having wide applications in food and pharmaceutical industry. In the present study, an exopolysaccharide producing bacterium was isolated from the root nodules of a leguminous plant and was studied for emulsification activity and biocompatibility using human dermal fibroblasts. Under optimum culture conditions, the purified EPS yield in modified YEM media was 2.8 g L−1 and was identified as β-glucan with the molecular weight 15.57 × 106 Da. The EPS showed high emulsifying activity against hydrocarbons such as petrol, kerosene, xylene, palm oil, coconut oil, and olive oil with emulsification index > 60% at 0.25 and 0.5% concentrations at 25 °C. The EPS was sensitive to high temperature, but the emulsions were stable at pH range 2–9 and in the salinity range of 1–20%. In vitro cell viability studies indicated that EPS was not cytotoxic at tested concentrations on human dermal fibroblasts moreover, it had proliferative activities. Hence, the EPS from Cronobacter sp. can be a good candidate for biotechnological application as a source of β-glucan with emulsifying and tissue regenerative properties.

Microbial exopolysaccharide: Sources, stress conditions, properties and application in food and environment: A comprehensive review

Production, purification, and functional characterization of glucan exopolysaccharide produced by Enterococcus hirae strain OL616073 of fermented food origin

Microbial exopolysaccharides (EPS), a carbohydrate biopolymer containing several distinct monosaccharides and non-carbohydrate substituents (molecular mass from 10 to 1000 kDa), constitute mainly sugar residues. The EPS is both homopolymer and heteropolymer supported their shape and size depend on degree of polymerization, derived from various microorganisms. Biosurfactants can be distinctive as the surface-bioactive biomolecules produced by microorganisms with broad array of applications. It has the viscoelastic quality maintained in the temperature range of 5–60 °C. Up to date, microbial EPS (biosurfactants) have found many applications including environmental remediation, pharmaceuticals, cosmetics, and food industry. First and foremost, the biosurfactants achieved a prospective interest for environmental applications of inorganic and organic contaminants, mainly in hydrocarbons, heavy metal removal from water and soil, enhanced oil recovery, and pharmaceutical products. The modified EPS act as suitable agent for biodegradation of textile dyes. It has potential and promising application in textiles, paper and pulp, coal, ceramic processing, health care and cosmetics, food industries, detergents, pesticide and herbicide formulation, uranium ore-processing and mechanical dewatering of peat, etc. The EPS and their derivatives which include alginate, dextran, gellan, pullulan, and xanthan are nontoxic, biodegradable drug carriers which help in drug delivery system. These molecules also exhibit immunomodulator, antibacterial, antioxidant, antibiofilm, antiviral, and antitumor activity and expand to scaffold engineering. The distinctive rheological properties of those molecules are helpful for jelly formation in food industry. It also acts as crystallization inhibitor which helps in ice-cream manufacturing, and their stable emulsion property maintains well-built emulsification indexes with soya bean oil and hydrocarbons. Thus, the biosurfactants act as multifunctional biomolecules with wide applications in various fields.

Bacillus licheniformis Tol1, a thermotolerant bacterial strain isolated from the Tolhuaca hot spring in Chile, was investigated for its genomic features and the functional properties of its exopolysaccharide (EPS). The whole-genome sequencing revealed ∼4.25 Mbp genome with a GC content of 45.9% and a rich repertoire of genes associated with environmental stress adaptation, antibiotic resistance, sporulation, biofilm formation, and EPS biosynthesis, including the presence of epsD and epsC. The strain also harbored intact prophage elements and a Type I-A CRISPR-Cas system, indicating potential horizontal gene transfer and genome plasticity. Confocal microscopy revealed robust biofilm formation at 45-55°C under neutral to slightly alkaline pH, with strong EPS matrix development. EPS production was optimized using OFAT and Response Surface Methodology (RSM), achieving a yield of 2.11 g L-1 under optimized conditions, which was further validated using an Artificial Neural Network (ANN) model (R 2 = 0.9909). The EPS exhibited promising antioxidant activity and significant emulsification potential across various vegetable oils, which were comparable or superior to commercial bacterial EPS xanthan gum. Notably, the EPS also showed cytotoxic effects against AGS gastric adenocarcinoma cells, reducing viability by 38.38 and 37% at 50-100 μg μL-1 concentrations, respectively, suggesting potential anticancer activity. Altogether, the study highlights B. licheniformis Tol1 as a multifunctional thermophile with valuable biotechnological potential, particularly for applications in food, pharmaceutical, and biomedical industries.

Exopolysaccharides (EPSs) produced by diverse group of microbial systems are rapidly emerging as new and industrially important biomaterials. Due to their unique and complex chemical structures and many interesting physicochemical and rheological properties with novel functionality, the microbial EPSs find wide range of commercial applications in various fields of the economy such as food, feed, packaging, chemical, textile, cosmetics and pharmaceutical industry, agriculture, and medicine. EPSs are mainly associated with high-value applications, and they have received considerable research attention over recent decades with their biocompatibility, biodegradability, and both environmental and human compatibility. However, only a few microbial EPSs have achieved to be used commercially due to their high production costs. The emerging need to overcome economic hurdles and the increasing significance of microbial EPSs in industrial and medical biotechnology call for the elucidation of the interrelations between metabolic pathways and EPS biosynthesis mechanism in order to control and hence enhance its microbial productivity. Moreover, a better understanding of biosynthesis mechanism is a significant issue for improvement of product quality and properties and also for the design of novel strains. Therefore, a systems-based approach constitutes an important step toward understanding the interplay between metabolism and EPS biosynthesis and further enhances its metabolic performance for industrial application. In this review, primarily the microbial EPSs, their biosynthesis mechanism, and important factors for their production will be discussed. After this brief introduction, recent literature on the application of omics technologies and systems biology tools for the improvement of production yields will be critically evaluated. Special focus will be given to EPSs with high market value such as xanthan, levan, pullulan, and dextran.