Current status of biotechnological production and applications of microbial exopolysaccharides

Structural characteristics, biotechnological production and applications of exopolysaccharides from Bacillus sp.: A comprehensive review

Exopolysaccharides (EPS) produced by Bacillus species display various biological activities and characteristics such as anti-oxidant, immunomodulatory, anti-bacterial, and bioadhesive effects. These attributes confer Bacillus species broad potential applications in diverse fields such as food, medicine, environment, and agriculture. Moreover, Bacillus-derived EPS are easier to produce and yield higher quantities than plant-derived polysaccharides. Despite these advantages, Bacillus-derived EPS still encounter numerous obstacles in industrial production and commercial applications, including elevated costs, the absence of mature fermentation tank production procedures, and the lack of systematic in vivo and in vitro activity and metabolic evaluation. Therefore, it is essential to gain insight into the current status of structure, production, and applications of Bacillus-derived EPS for facilitating their future broader application. This paper provides a comprehensive overview of the current research on the production, separation, characteristics and applications of these related biological products. Furthermore, this paper summarizes the current challenges impeding industrial production of Bacillus-derived EPS, along with potential solutions, and their prospective applications in enhancing the attributes of beneficial biofilms, laying a solid scientific foundation for the applications of Bacillus-derived EPS in industry and agriculture.

Recent advance on the production of microbial exopolysaccharide from waste materials

Polysaccharide has been widely used in the fields of industry, agriculture, food and medicine because of its excellent physicochemical properties and bioactivities. Compared to plant and animal polysaccharides, microbial exopolysaccharide has advantages of occupying less cultivated land, short fermentation period, controllable fermentation process and not restricted by seasons. However, due to the deterioration of global climates and outbreak of conflicts, food crisis has become more and more serious. Therefore, searching alternative substrates for microbial exopolysaccharide production has attracted worldwide attention, waste materials might be an ideal substitute due to its high-content nutrients. Present work discussed and reviewed the production of microbial exopolysaccharide from molasses, cheese whey, lignocellulosic biomass, fruit pomace and/or husk, crude glycerol and kitchen waste. It was found that commercial grade exopolysaccharides were mainly produced from waste materials via submerged fermentation, and pretreatment of waste materials is a commonly used strategy. Although industrial production of microbial exopolysaccharides with waste materials as substrate has not been reported, we hoped that this work could not only provide contribution for efficient utilization of waste materials, but also help for alleviating global food crises.

Effect of fermentation with selected lactic acid bacteria strains on the molecular and technological properties of sorghum batters

This study provides an in-depth investigation of the relationship between fermentation-induced molecular changes and techno-functional properties of sorghum flour, using three lactic acid bacteria (LAB) strains - Lactobacillus delbrueckii subsp. bulgaricus 1932, Leuconostoc spp. 4454, and Lacticaseibacillus casei 4339. Fermentation at 25 °C for 15 h induced significant molecular changes, including the reduction of low molecular weight fractions (∼0.7 kDa), and depolymerization of starch and fiber (HPSEC analysis). Proton mobility and relaxation analyses (1H LR-NMR) revealed matrix breakdown and stronger water-biopolymer interactions. These molecular changes were closely associated with improved technological properties, including enhanced starch gelatinization (higher enthalpy changes, DSC) and better pasting properties. Changes in structure and molecular interactions likely contributed to the increased viscosity of sorghum, even in the absence of exopolysaccharide production. This study bridges the gap between molecular-level transformations with functional outcomes, providing insights into tailoring fermentation processes for the development of sustainable and innovative sorghum-based foods.

Statistical Optimization of Exopolysaccharide and Biomass Production by Mangrove Fungi Fusarium equiseti ANP2 and its Potential Application as Bioemulsifier and Chelator

The rationale of the study is to explore the bio functional industrial potential and optimized culture conditions of a Manno glucan heteropolysaccharide MF-1 (purified EPS fraction) produced by a newly discovered mangrove derived fungi Fusarium equiseti ANP2, isolated from the Krishna River delta mangrove sediments. Response surface methodology (RSM) was employed to optimize fungal EPS and Biomass production, achieving a significant 1.4-fold increase to 6.94 g/L in EPS yield and a 2.1-fold increase in biomass production. RSM identified optimal levels of glucose, NH₄NO₃, NaCl, leucine, temperature, and pH, while minimizing the required glucose and nitrogen content compared to conventional methods. Notably, MF-1 exhibited promising emulsification potential (69.5% n-hexadecane emulsification), suggesting its prospective role as a novel emulsifier, particularly for n-hexadecane-based applications. Additionally, MF-1 also displayed a chelating activity for Fe2⁺ ions, suggesting its applicability as a natural chelating agent. The current study optimized the EPS production using RSM design and explored its potential for industrial applications as emulsification and chelating properties of the purified EPS fraction. Future research could explore the structural modifications of the fungal EPS to enhance its functionalities and delve deeper into the mechanisms governing EPS and biomass for large-scale, sustainable industrial production.

Developing a mutant strain of Pseudomonas composti ODT-54 for enhanced production of Psl extracellular polysaccharide

In our previous study, a strain of Pseudomonas composti ODT-54 was isolated from the oyster digestive tissues. This strain is capable of producing Psl exopolysaccharides (EPS), which are directly involved in the specific binding to norovirus GII.6 P proteins. Here, we constructed an ODT-54 Psl EPS overexpression strain ODT-54 psl(+) by substituting an exogenous arabinose-inducible promoter for the native promoter of the psl gene cluster. ODT-54 psl(+) produced 50-70% more Psl EPS in FAB medium with 20 g/L arabinose induction compared to ODT-54, according to ELISA analyses. Furthermore, a 50% increase in binding to GII.6 P proteins was observed for ODT-54 psl(+). These findings confirmed the success of the construction of the ODT-54 Psl EPS overexpression strain. This work provides important experimental material and helps further explore the structure of Psl EPS from P. composti.

Complex arabinose-containing polysaccharides from cyanobacterium Nostoc sp.: Extraction, structural characterization and antioxidant activity

Freshwater Nostoc sp. polysaccharides (NSPs) have not been extensively studied, particularly regarding their structural and biological characteristics. This study assessed the extracted NSPs through a multi-faceted characterization approach using 1H and 13C NMR, FTIR spectroscopy, HP-SEC and HPAEC-PAD. The study presented novel insights into the extracted polysaccharide composition, extraction efficiency, and antioxidant activities. NSPs were extracted using two different ranges of heating regimes: cold (25 °C) and hot (95 °C), with hot extraction yielding up to 34.9 % of NSPs compared to 27.6 % from cold extraction. The NSPs were non-sulfated and mainly composed of four monosaccharide residues: (1 → 3)-β-d-mannopyranose-(1 → 4)-β-l-arabinopyranose-(1 → 4)-β-d-glucuronic acid-(1 → 4)-β-d-glucopyranose. Some glucose units were 6-O-methylated, and minor sidechain glycosylation by other monosaccharides was observed. β-d-glucuronic acid was present in higher amounts. The polysaccharides from the inner fluid (IF) fraction exhibited a higher molecular weight (up to 480 kDa) compared to outer layer (OL) fractions. The total phenolic content (TPC: 0.2 ± 0.0-2.8 ± 0.0 %), total sugar (9.1 ± 0.8-67.8 ± 0.4 %), and protein (1.2 ± 0.1-25.9 ± 0.6 %) content were determined. NSPs, especially from cold extraction (1B) exhibited the highest antioxidant activity, have potential applications in the skincare, food, pharmaceutical, and biotechnology industries due to their high yield, unique structural features.

Preparation and characterization of the octenyl succinic anhydride (OSA) modified sphingan WL gum as novel biopolymeric surfactants

Combining polymer and surfactant in one agent namely polymeric surfactants with both high viscosity and surface activity has become a viable alternative for the traditional enhanced oil recovery (EOR) processes. With the purpose of developing new polymeric surfactants, the biopolymer flooding agent sphingan WL gum was modified by octenyl succinic anhydride (OSA) through the esterification reaction. The effects of molecular weight (MW) of WL and the OSA: WL ratio on the properties of the products were investigated. As the OSA concentration increased, the degree of substitution was increased. WL2 with the medium MW was the best substrate and the optimal OSA:WL was 1:1; the obtained sample OSA-WL2-2 exhibited good viscosity and surface activity. Compared with WL2, its viscosity (23 mPa·s) was increased by 75.98 %; the surface tension decreased from 59.30 mN/m to 48.13 mN/m, and the critical micelle concentration was 2.29 mg/mL; the emulsifying activity index was increased by 57.18 %. OSA-WL2-2 also had higher elastic modulus G' and salt tolerance due to its increased MW and intermolecular association among the hydrophilic and hydrophobic groups. OSA-WL2-2 showed higher oil washing efficiency (78.6 %) than the commonly-used polyacrylamide, SDS and modified cellulose samples and made it a potential flooding agent in EOR.

Microbial exopolysaccharides: Classification, biosynthetic pathway, industrial extraction and commercial production to unveil its bioprospection: A comprehensive review

Polysaccharides, found universally in all living-species, exhibit diverse biochemical structures and play crucial roles in microorganisms, animals, and plants to defend against pathogens, environmental stress and climate-changing. Microbial exopolysaccharides are essential for cell adhesion and stress resilience and using them has notable advantages over synthetic polysaccharides. Exopolysaccharides have versatile structures and physicochemical properties, used in food systems, therapeutics, cosmetics, agriculture, and polymer industries. Immense economic and infrastructural constraints hinder its widespread commercial use, necessitating a deeper understanding of metabolic-pathways amidst changing environmental climate that influences the biomass composition of EPS-producing wild-microbes. Green and sustainable extraction of EPS from microbes followed by commercial product development has still not been exploited comprehensively. Yield of EPS production vary from 0.1 to 3 g/g of cell weight, influenced by fermentation conditions. Economic barriers, including substrate and processing costs, limit commercial viability. Key biosynthetic pathways involve glycosyltransferases enzymes, whose regulatory network gaps and substrate specificity remain areas for optimization. Addressing these could enhance yields and lower production costs. Review illustrates various microbial-exopolysaccharides, influencing factors of production, and offer valuable insights on the bioplastic, biofuel, agri-bioproduct, and biomedicine. But their bioprospecting potential is yet to be exhaustively explored, along with their pros and cons nor documented comprehensively in scientific literature.

Vat-Based 3D-Bioprinted Scaffolds from Photocurable Bacterial Levan for Osteogenesis and Immunomodulation

Emerging techniques of additive manufacturing, such as vat-based three-dimensional (3D) bioprinting, offer novel routes to prepare personalized scaffolds of complex geometries. However, there is a need to develop bioinks suitable for clinical translation. This study explored the potential of bacterial-sourced methacrylate levan (LeMA) as a bioink for the digital light processing (DLP) 3D bioprinting of bone tissue scaffolds. LeMA was successfully synthesized, characterized, and used to fabricate 3D-bioprinted scaffolds with excellent printability and physicochemical properties. In vitro studies demonstrated superior cytocompatibility of 15% w/v LeMA gels compared to 20% gels. 15% LeMA gels supported osteogenic differentiation , as evidenced by alkaline phosphatase activity and mineral deposition by MC3T3 pre-osteoblasts. Importantly, the LeMA hydrogels positively modulated the macrophage phenotype, promoting the expression of the anti-inflammatory marker CD206. These findings suggest that 3D-printed LeMA scaffolds can create a favorable microenvironment for bone regeneration, highlighting their potential for tissue repair and regeneration applications.

Bacterial exopolysaccharides: Characteristics and antioxidant mechanism

Bacterial exopolysaccharides (EPS) are secondary metabolites of microorganisms which play important roles in adhesion, protection, biofilm formation, and as a source of nutrition. Compared with polysaccharides obtained from animal and plant species, bacterial polysaccharides have significant advantages in terms of production cost and large-scale production due to their abundant metabolic pathways and efficient polysaccharide production capacity. Most extracellular polysaccharides are water-soluble, and some are insoluble, such as bacterial cellulose. Some soluble bacterial EPS also have biological activities such as anticancer, antioxidant, antibacterial and immunomodulatory activities. These biological activities are mainly affected by the molecular weight, monosaccharide type, composition and structure of EPS. In recent years, bacterial EPS are considered as novel functional polysaccharides with important application prospects, especially in free radical scavenging and antioxidation. This review focuses on the characteristics of bacterial EPS, their ability to scavenge free radicals and their corresponding antioxidant mechanisms, and summarizes the relationship between different structures (such as monosaccharide composition, functional groups, molecular weight, etc.) and antioxidant activities. It provides a new idea for the development of more bioactive bacterial EPS antioxidants, points out a new direction for the commercial production of natural, safe and economical polysaccharide drugs and health products.

Metabolomics analysis based on UHPLC-QTOF-MS/MS to explore the synthesis mechanism and culture conditions optimization of Penicillium EF-2 exopolysaccharide

Penicillium exopolysaccharide (EPS) inhibits galactose lectins and enhances immunity. However, EPS production is low and its synthesis mechanism remains unclear. Penicillium EF-2 strains with high EPS production were selected for this study, and Penicillium fermentation conditions were subsequently improved. The optimal culture conditions were 30 g/L lactose, 6 g/L yeast extract powder, 4 d seed age, 10 % inoculation amount, 3 d of secondary fermentation time, and the final EPS yield was 3.97 g/L. UHPLC-Q-TOF-MS/MS was used to explore the mechanism of EPS synthesis at the metabolic level. Optimal carbon source: lactose and optimal nitrogen source: yeast extract can provide precursors for EPS synthesis through related metabolic pathways. Moreover, regulating the energy, vitamin, and lipid metabolic pathways created favourable conditions for EPS synthesis and secretion. These findings explain the mechanism of EPS synthesis at the metabolic level and provide a theoretical basis for optimising and industrialising EPS production.

Structural Characterization and Biological Properties Analysis of Exopolysaccharides Produced by Weisella cibaria HDL-4

An exopolysaccharide (EPS)-producing strain, identified as Weissella cibaria HDL-4, was isolated from litchi. After separation and purification, the structure and properties of HDL-4 EPS were characterized. The molecular weight of HDL-4 EPS was determined to be 1.9 × 10⁶ Da, with glucose as its monosaccharide component. Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance (NMR) analyses indicated that HDL-4 EPS was a D-glucan with α-(1→6) and α-(1→4) glycosidic bonds. X-ray diffraction (XRD) analysis revealed that HDL-4 EPS was amorphous. Scanning electron microscope (SEM) and atomic force microscope (AFM) observations showed that HDL-4 EPS possesses pores, irregular protrusions, and a smooth layered structure. Additionally, HDL-4 EPS demonstrated significant thermal stability, remaining stable below 288 °C. It exhibited a strong metal ion adsorption activity, emulsification activity, antioxidant activity, and water-retaining property. Therefore, HDL-4 EPS can be extensively utilized in the food and pharmaceutical industries as an additive and prebiotic.

Microalgal extracellular polymeric substances (EPS) and their roles in cultivation, biomass harvesting, and bioproducts extraction

Microalgae extracellular polymeric substances (EPS) are complex high-molecular-weight polymers and the physicochemical properties of EPS strongly affect the core features of microalgae cultivation and resource utilization. Revealing the key roles of EPS in microalgae life-cycle processes in an interesting and novelty topic to achieve energy-efficient practical application of microalgae. This review found that EPS showed positive effect in non-gas uptake, extracellular electron transfer, toxicity resistance and heterotrophic symbiosis, but negative impact in gas transfer and light utilization during microalgae cultivation. For biomass harvesting, EPS favored biomass flocculation and large-size cell self-flocculation, but unfavored small size microalgae self-flocculation, membrane filtration, charge neutralization and biomass dewatering. During bioproducts extraction, EPS exhibited positive impact in extractant uptake, but the opposite effect in cellular membrane permeability and cell rupture. Future research on microalgal EPS were also identified, which offer suggestions for comprehensive understanding of microalgal EPS roles in various scenarios.

Revolutionizing cancer treatment: Harnessing the power of terrestrial microbial polysaccharides

Cancer treatment faces numerous challenges, such as inadequate drug targeting, steep price tags, grave toxic side effects, and limited therapeutic efficacy. Therefore, there is an urgent need for a safe and effective new drug to combat cancer. Microbial polysaccharides, complex and diverse biological macromolecules, exhibit significant microbial variability and uniqueness. Studies have shown that terrestrial microbial polysaccharides possess a wide range of biological activities, including immune enhancement, antioxidant properties, antiviral effects, anti-tumour potential, and hypoglycemic functions. To delve deeper into the structure-activity relationship of these land-based microbial polysaccharides against cancer, we conducted a comprehensive review and analysis of anti-cancer literature published between 2020 and 2024. The anticancer efficacy of terrestrial microbial polysaccharides is influenced by multiple factors, including the microbial species, existing form, chemical structure, and polysaccharide purity. According to the literature, an optimal molecular weight and good water solubility are essential for demonstrating anticancer activity. Furthermore, the addition of mannose and galactose has been found to significantly enhance the anticancer properties of these polysaccharides. These insights will serve as a valuable reference for future research and progress in the field of cancer drug therapy, particularly with regards to terrestrial microbial polysaccharides.

Antioxidant and Emulsifying Activity of the Exopolymer Produced by Bacillus licheniformis

The exopolymer (ESPp) was obtained from Bacillus licheniformis IDN-EC, composed of a polyglutamic acid and polyglycerol phosphate chain O-substituted with αGal moieties (αGal/αGlcNH2 3:1 molar ratio) and with a 5000 Da molecular weight. The cytotoxicity activity of EPSp was determined by reducing the MTT (3-[4,5-dimethyl-thiazol-2-yl]-2,5-diphenyltetrazolium bromide) to formazan on HeLa cells. This EPS did not show cytotoxicity against the tested cell line. The ESPp presented great advantages as an antioxidant with free radical scavenging activities (1,1-diphenyl-2-picryl-hydrazyl radical (DPPH),hydroxyl radical (OH), and superoxide anion (O2-)) (65 ± 1.2%, 98.7 ± 1.9%, and 97 ± 1.7%), respectively. Moreover, EPSp increased the enzyme activity for catalase (CAT) and glutathione peroxidase (GSH-Px) in HeLa cells (CAT, 2.6 ± 0.24 U/mL; and GSH-Px, 0.75 ± 0.3 U/L). The presence of ESPp showed a significant protective effect against H2O2 in the cell line studied, showing great viability (91.8 ± 2.8, 89.9 ± 2.9, and 93.5 ± 3.6%). The EPSp presented good emulsifying activity, only for vegetable oils, olive oil (50 ± 2.1%) and sesame (72 ± 3%). Sesame was effective compared to commercials products, Triton X-100 (52.38 ± 1.6%), Tween 20 (14.29 ± 1.1%), and sodium dodecyl sulphate (SDS) (52.63 ± 1.6%). Furthermore, the EPS produced at 0.6 M has potential for environmental applications, such as the removal of hazardous materials by emulsification whilst resulting in positive health effects such as antioxidant activity and non-toxicity. EPSp is presented as a good exopolysaccharide for various applications.

Bioprospecting of exopolysaccharides from the endophytic fungi Epicoccum sorghinum AMFS4, for its structure, composition, bioactivities and application in seed priming

The endophytic fungi, Epicoccum sorghinum AMFS4 was investigated for its metabolic components and composition of bioactive exopolysaccharides (EPS). Metabolic analysis of the ethyl acetate extract majorly detected sugars derivatives such as, 4-Cholesten-3-one semicarbazone (20.9%), d-Fructose (18.96%), and α-d-Galactopyranosiduronicacid (1.71%). The growth curve and EPS yield were determined as 12.22 ± 1.02 g/L and 7.41 ± 0.32 g/L (dry weight) respectively on day 8. The deproteined EPS has been characterised with pyranose ring linked by α-glycosidic bonds, composing fructose, galactose and glucose monosaccharides validated by HPLC. Total sugar content was found to be 93.18 ± 0.81% with detection of proteins and uronate. The viscous EPS appeared filamentous under SEM observation and behaves as emulsifier with notable antioxidant properties. Priming of EPS on tomato seeds showed early induction of secondary rooting than in the control seedlings. Thus, E. sorghinum AMFS4 synthesises bioactive EPS with simple carbohydrate structure, good water absorption and significant metabolic influence on seed germination.

The effects of different impeller combinations in the Sphingan WL gum fermentation process

The fermentation of the high-viscosity polysaccharide WL gum has always been associated with poor mass transfer. Appropriate impeller configurations are key factors in maintaining homogeneity and sufficient mass transfer conditions. Therefore, a flat-folded disc turbine impeller (FFDT) taking into account both the reduced cavitation effect and the increased contact area was designed. Besides, a curved cross impeller (CC) and a fishbone-shaped impeller (FS) generating axial flow were also designed. The energy consumption and efficiency of the designed impellers and eight reported impellers were evaluated through fermentation and principal component analysis (PCA). Compared to the commonly-used six-blade flat-blade disc turbine (FBDT), the ungassed power number of FFDT was reduced by 50 %. Combinations of six-blade Brumajin impeller (BM) + FFDT and CC + FFDT produced high WL gum production and viscosity (34.0 g/L, 35.50 g/L, and 62.64 Pa·s, 61.68 Pa·s, respectively) and were suitable impellers for WL biosynthesis. WL gum from BM + FFDT showed higher viscosity, viscoelasticity, and molecular weight than that from FBDT + FBDT. In addition, fewer amino acids and pyruvic acid intermediates were formed using BM + FFDT, indicating a greater metabolic flux towards WL gum synthesis. This work provided an important reference for the design of impellers in high-viscosity fermentation systems.

Optimized scleroglucan production by Athelia rolfsii and in vitro Sclg-5-fluorouracil release investigations

Scleroglucan is a notable member of the β-glucan microbial polysaccharides with a long tradition of industrial and therapeutic use. The local strain, previously identified as Athelia rolfsii TEMG MH 236106 produced an appreciable amount of scleroglucan using glucose as a carbon source and yeast extract as a nitrogen source. Plackett-Burman design was employed to effectively screen critical medium composition, culture, and fermentation conditions. Athelia rolfsii TEMG MH 236106 produced the maximum amount of scleroglucan (18.12 g/L) with a 45.3 % glucose conversion. Out of the eleven variables, the most effective factors showing a high level of significance are as follows: glucose, yeast extract, citric acid, inoculum disc numbers, culture volume and incubation time. An update to maximize scleroglucan production in the central composite design for four parameters (glucose and yeast extract concentrations, disc number, medium volume and incubation time) with 31 runs was applied and the production of scleroglucan reached its maximum at 31.56 g/L with 78.9 % glucose conversion. Three models of Sclg-5-fluorouracil complexes have been employed to study in vitro drug release investigations. Hence, the Sclg-5-FU (5 and 10 mg/mL) models appeared to be the most suitable for drug administration due to their concentration and distribution within capsules.

A dual catalytic functionalized hollow mesoporous silica-based nanocarrier coated with bacteria-derived exopolysaccharides for targeted delivery of irinotecan to colorectal cancer cells

In this study, we introduced a multifunctional hollow mesoporous silica-based nanocarrier (HMSN) for the targeted delivery of irinotecan (IRT) to colorectal cancer cells. Due to their large reservoirs, hollow mesoporous silica nanoparticles are suitable platforms for loading significant amounts of drugs for sustained drug release. To respond to pH and redox, HMSNs were functionalized with cerium and iron oxides. Additionally, they were coated with bacterial-derived exopolysaccharide (EPS) as a biocompatible polymer. In vitro analyses revealed that cytotoxicity induced in cancer cells through oxidative stress, mediated by mature nanocarriers (EPS.IRT.Ce/Fe.HMSN), was surprisingly greater than that caused by free drugs. Cerium and iron ions, in synergy with the drug, were found to generate reactive oxygen species when targeting the acidic pH within lysosomes and the tumor microenvironment. This, in turn, triggered cascade reactions, leading to cell death. In vivo experiments revealed that the proposed nanocarriers had no noticeable effect on healthy tissues. These findings indicate the selective delivery of the drug to cancerous tissue and the induction of antioxidant effects due to the dual catalytic properties of cerium in normal cells. Accordingly, this hybrid drug delivery system provides a more effective treatment for colorectal cancer with the potential for cost-effective scaling up.

Effects of different stress conditions on the production, bioactivities, physicochemical and structural characteristics of exopolysaccharides synthetized by Schleiferilactobacillus harbinensis Z171

This study systematically investigated the effects of stress conditions including temperature, pH, H2O2, NaCl, antibiotics on the production and in vitro cholesterol-lowering activity of the exopolysaccharide (EPS) synthetized by Schleiferilactobacillus harbinensis Z171. Additionally, the influences of the optimal stress condition combined with different carbon sources on EPS production were examined, shedding light on the structural characteristics, physicochemical properties and bioactivities of EPSs. The results demonstrated that the EPS produced under H2O2 stress was optimal and presented excellent resistance to simulated gastric juice and α-amylase. Three main fractions, denoted as G-EPS1, F-EPS1 and S-EPS1, were isolated by cellulose DEAE-52 chromatography from crude EPSs synthetized using glucose, fructose and sucrose as carbon sources, respectively. Among them, F-EPS1 possessed the highest cholesterol-lowering, antioxidant and hypoglycemic activities, with the highest molecular weight 91.03 kDa, largest particle size 40.14 nm and apparent viscosity 288.2 mPa·s. Three EPSs exhibited irregular sheet-like and granular structures with good thermal stability. Structural characterization of F-EPS1a (a purified fraction from F-EPS1) revealed that it was a mannan mainly composed of →2)-α-D-Manp-(1→, →3)-α-Manp-(1→ and →2,6)-α-D-Manp-(1→ with branch chains containing α-D-Manp-(1→. F-EPS1a has more potential to be a natural cholesterol-lowering, hypoglycemic and antioxidant supplements in the food industry.

NMR analysis of the side-group substituents in welan gum in comparison to gellan gum

The physicochemical properties and applications of polysaccharides are highly dependent on their chemical structures, including the monosaccharide composition, degree of substitution, and position of substituent groups in the backbone. The occurrence of side groups or side chains in the chain backbone of polysaccharides is often an essential factor influencing their conformational and physicochemical properties. Welan gum produced by the fermentation of Sphingomonas sp. ATCC 31555 microorganisms has been widely used in food, construction, and oil drilling fields. While understanding the physicochemical properties of welan gum solution has been highly developed, there is still little information about the determination strategy of the glycosyl side groups in welan gum. In this study, the NMR method was established to quantitatively determine the substituent groups in the chain backbone of welan gum. The delicate chemical structures of welan gum obtained at different fermentation conditions were clarified. The composition and content of side substituents were also identified by high-performance liquid chromatography to confirm the accuracy of NMR analysis. The quantitative determination of substituent groups in gellan gum based on NMR analysis was also elaborated for comparison. This work provides insights for profoundly understanding the structure-function relationship of welan gum.

Polyhydroxyalkanoates and exopolysaccharides: An alternative for valuation of the co-production of microbial biopolymers

Polyhydroxyalkanoates (PHAs) and exopolysaccharides (EPSs) belong to a class of abundant biopolymers produced by various fermenting microorganisms. These biocompounds have high value-added potential and can be produced concurrently. Co-production of PHAs and EPSs is a strategy employed by researchers to reduce costs associated with large-scale production. EPSs and PHAs are non-toxic, biocompatible, and biodegradable, making them suitable for various industrial sectors, including packaging and the medical and pharmaceutical industries. These biopolymers can be derived from agro-industrial residues, thus contributing to the bioeconomy by producing high-value-added products. This review investigates approaches for simultaneously synthesizing PHAs and EPSs using different carbon sources and microorganisms.

Investigation of exopolysaccharide formation and its impact on anaerobic succinate production with Vibrio natriegens

Vibrio natriegens is an emerging host for biotechnology due to its high growth and substrate consumption rates. In industrial processes typically fed-batch processes are applied to obtain high space-time yields. In this study, we established an aerobic glucose-limited fed-batch fermentation with the wild type (wt) of V. natriegens which yielded biomass concentrations of up to 28.4 gX  L-1 . However, we observed that the viscosity of the culture broth increased by a factor of 800 at the end of the cultivation due to the formation of 157 ± 20 mg exopolysaccharides (EPS) L-1 . Analysis of the genomic repertoire revealed several genes and gene clusters associated with EPS formation. Deletion of the transcriptional regulator cpsR in V. natriegens wt did not reduce EPS formation, however, it resulted in a constantly low viscosity of the culture broth and altered the carbohydrate content of the EPS. A mutant lacking the cps cluster secreted two-fold less EPS compared to the wt accompanied by an overall low viscosity and a changed EPS composition. When we cultivated the succinate producer V. natriegens Δlldh Δdldh Δpfl Δald Δdns::pycCg (Succ1) under anaerobic conditions on glucose, we also observed an increased viscosity at the end of the cultivation. Deletion of cpsR and the cps cluster in V. natriegens Succ1 reduced the viscosity five- to six-fold which remained at the same level observed at the start of the cultivation. V. natriegens Succ1 ΔcpsR and V. natriegens Succ1 Δcps achieved final succinate concentrations of 51 and 46 g L-1 with a volumetric productivity of 8.5 and 7.7 gSuc L-1  h-1 , respectively. Both strains showed a product yield of about 1.4 molSuc molGlc -1 , which is 27% higher compared with that of V. natriegens Succ1 and corresponds to 81% of the theoretical maximum.

Marine versus Non-Marine Bacterial Exopolysaccharides and Their Skincare Applications

Bacteria are well-known to synthesize high molecular weight polysaccharides excreted in extracellular domain, which constitute their protective microenvironment. Several bacterial exopolysaccharides (EPS) are commercially available for skincare applications in cosmetic products due to their unique structural features, conferring valuable biological and/or textural properties. This review aims to give an overview of bacterial EPS, an important group of macromolecules used in cosmetics as actives and functional ingredients. For this purpose, the main chemical characteristics of EPS are firstly described, followed by the basics of the development of cosmetic ingredients. Then, a focus on EPS production, including upstream and downstream processes, is provided. The diversity of EPS used in the cosmetic industry, and more specifically of marine-derived EPS is highlighted. Marine bacteria isolated from extreme environments are known to produce EPS. However, their production processes are highly challenging due to high or low temperatures; yield must be improved to reach economically viable ingredients. The biological properties of marine-derived EPS are then reviewed, resulting in the highlight of the challenges in this field.

Production of Bacterial Exopolysaccharides: Xanthan and Bacterial Cellulose

Recently, degradable biopolymers have become increasingly important as potential environmentally friendly biomaterials, providing a wide range of applications in various fields. Bacterial exopolysaccharides (EPSs) are biomacromolecules, which due to their unique properties have found applications in biomedicine, foodstuff, textiles, cosmetics, petroleum, pharmaceuticals, nanoelectronics, and environmental remediation. One of the important commercial polysaccharides produced on an industrial scale is xanthan. In recent years, the range of its application has expanded significantly. Bacterial cellulose (BC) is another unique EPS with a rapidly increasing range of applications. Due to the great prospects for their practical application, the development of their highly efficient production remains an important task. The present review summarizes the strategies for the cost-effective production of such important biomacromolecules as xanthan and BC and demonstrates for the first time common approaches to their efficient production and to obtaining new functional materials for a wide range of applications, including wound healing, drug delivery, tissue engineering, environmental remediation, nanoelectronics, and 3D bioprinting. In the end, we discuss present limitations of xanthan and BC production and the line of future research.

Flux balance analysis-based metabolic modeling of microbial secondary metabolism: Current status and outlook

In microorganisms, different from primary metabolism for cellular growth, secondary metabolism is for ecological interactions and stress responses and an important source of natural products widely used in various areas such as pharmaceutics and food additives. With advancements of sequencing technologies and bioinformatics tools, a large number of biosynthetic gene clusters of secondary metabolites have been discovered from microbial genomes. However, due to challenges from the difficulty of genome-scale pathway reconstruction and the limitation of conventional flux balance analysis (FBA) on secondary metabolism, the quantitative modeling of secondary metabolism is poorly established, in contrast to that of primary metabolism. This review first discusses current efforts on the reconstruction of secondary metabolic pathways in genome-scale metabolic models (GSMMs), as well as related FBA-based modeling techniques. Additionally, potential extensions of FBA are suggested to improve the prediction accuracy of secondary metabolite production. As this review posits, biosynthetic pathway reconstruction for various secondary metabolites will become automated and a modeling framework capturing secondary metabolism onset will enhance the predictive power. Expectedly, an improved FBA-based modeling workflow will facilitate quantitative study of secondary metabolism and in silico design of engineering strategies for natural product production.

Production and applications of pullulan from lignocellulosic biomass: Challenges and perspectives

Pullulan is an exopolysaccharide produced by Aureobasidium pullulans, with interesting characteristics which lead to its application in industries such as pharmaceuticals, cosmetics, food, and others. To reduce production costs for industrial applications, cheaper raw materials such as lignocellulosic biomass can be utilized as a carbon and nutrient source for the microbial process. In this study, a comprehensive and critical review was conducted, encompassing the pullulan production process and the key influential variables. The main properties of the biopolymer were presented, and different applications were discussed. Subsequently, the utilization of lignocellulosics for pullulan production within the framework of a biorefinery concept was explored, considering the main published works that deal with materials such as sugarcane bagasse, rice husk, corn straw, and corn cob. Next, the main challenges and future prospects in this research area were highlighted, indicating the key strategies to favor the industrial production of pullulan from lignocellulosic biomasses.

Purification, characterization and probiotic proliferation effect of exopolysaccharides produced by Lactiplantibacillus plantarum HDC-01 isolated from sauerkraut

In this study, an exopolysaccharide (EPS)-producing strain of Lactiplantibacillus plantarum HDC-01 was isolated from sauerkraut, and the structure, properties and biological activity of the studied EPS were assessed. The molecular weight of the isolated EPS is 2.505 × 10⁶ Da. Fourier transform infrared spectrometry (FT-IR) and nuclear magnetic resonance (NMR) results showed that the EPS was composed of glucose/glucopyranose subunits linked by an α-(1 → 6) glycosidic bond and contained an α-(1 → 3) branching structure. X-ray diffraction (XRD) analysis revealed the amorphous nature of the EPS. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) showed that the isolated EPS had a smooth and compact surface with several protrusions of varying lengths and irregularly shaped material. Moreover, the studied EPS showed good thermal stability, water holding capacity, and milk coagulation ability and promoted the growth of probiotics. L. plantarum EPS may be used as prebiotics in the fields of food and medicine.

Exopolysaccharides Producing Bacteria: A Review

Bacterial exopolysaccharides (EPS) are essential natural biopolymers used in different areas including biomedicine, food, cosmetic, petroleum, and pharmaceuticals and also in environmental remediation. The interest in them is primarily due to their unique structure and properties such as biocompatibility, biodegradability, higher purity, hydrophilic nature, anti-inflammatory, antioxidant, anti-cancer, antibacterial, and immune-modulating and prebiotic activities. The present review summarizes the current research progress on bacterial EPSs including their properties, biological functions, and promising applications in the various fields of science, industry, medicine, and technology, as well as characteristics and the isolation sources of EPSs-producing bacterial strains. This review provides an overview of the latest advances in the study of such important industrial exopolysaccharides as xanthan, bacterial cellulose, and levan. Finally, current study limitations and future directions are discussed.

Relationship of Gene-Structure-Antioxidant Ability of Exopolysaccharides Derived from Lactic Acid Bacteria: A Review

Polysaccharides derived from lactic acid bacteria (LAB) have widespread industrial applications owing to their excellent safety profile and numerous biological properties. The antioxidant activity of exopolysaccharides (EPS) offers defense against disease conditions caused by oxidative stress. Several genes and gene clusters are involved in the biosynthesis of EPS and the determination of their structures, which play an important role in modulating their antioxidant ability. Under conditions of oxidative stress, EPS are involved in the activation of the nonenzyme (Keap1-Nrf2-ARE) response pathway and enzyme antioxidant system. The antioxidant activity of EPS is further enhanced by the targeted alteration of their structures, as well as by chemical methods. Enzymatic modification is the most commonly used method, though physical and biomolecular methods are also frequently used. A detailed summary of the biosynthetic processes, antioxidant mechanisms, and modifications of LAB-derived EPS is presented in this paper, and their gene-structure-function relationship has also been explored.

A review on the emerging conversion technology of cellulose, starch, lignin, protein and other organics from vegetable-fruit-based waste

A large amount of vegetable-fruit-based waste (VFBW) belonging to agricultural waste is produced around the world every year, imposing a huge burden on the environment and sustainable development. VFBW contains a lot of water and useful organic compounds (e.g., cellulose, minerals, starch, proteins, organic acids, lipids, and soluble sugars). Taking into account the composition characteristics and circular economy of VFBW, many new emerging conversion technologies for the treatment of VFBW (such as hydrothermal gasification, ultrasound-assisted extraction, and synthesis of bioplastics) have been developed. This review summarizes the current literature discussing the technical parameters, process, mechanism, and characteristics of various emerging conversion methods, as well as analyzing the application, environmental impact, and bio-economy of by-products from the conversion process, to facilitate solutions to the key problems of engineering cases using these methods. The shortcomings of the current study and the direction of future research are also highlighted in the review.

Integrative analysis of genomic and metabolomic data reveals key metabolic pathways involved in lipid and carotenoid biosynthesis in oleaginous red yeast Rhodosporidiobolus odoratus XQR

Rhodosporidiobolus odoratus, one of the oleaginous red yeasts, is gaining biotechnological importance for their ability to produce microbial lipids and carotenoids. However, to date, the genomic resource underling lipid and carotenoid biosynthesis in R. odoratus has not been reported. Here, we reported the first genome assembly of R. odoratus using a combination of PacBio and Illumina techniques. The final genome assembly is 23.74 Mb in size, containing 52 scaffolds with a N50 length of 1200,460 bp and a GC content of 56.90%. Benchmarking Universal Single-Copy Orthologs (BUSCO) assessment showed that our assembly contains 94.23% of Basidiomycota universal single-copy orthologs. The genome was predicted to contain 4986 protein-coding genes, 4967 of which were functionally annotated. Metabolomic profiling identified 574 lipids, 3 carotenoids, and 208 volatile organic compounds synthesized by R. odoratus. Integrative analysis of genomics and metabolomics provides insights into the biosynthesis of lipid, carotenoid, and other bioactive compounds in R. odoratus. Collectively, the results presented herein greatly enhance our understanding of R. odoratus in lipids and carotenoids biosynthesis, and thus further accelerate its fundamental molecular investigations and biotechnological applications.

Structural characterization of a novel fucosylated trisaccharide prepared from bacterial exopolysaccharides and evaluation of its prebiotic activity

Fucosylated oligosaccharides have promising prospects in various fields. In this study, a fucosylated trisaccharide (GFG) was separated from the acidolysis products of exopolysaccharides from Clavibacter michiganensis M1. Structural characterization demonstrated that GFG consists of glucose, galactose, and fucose, with a molecular weight of 488 Da. Nuclear magnetic resonance analysis showed that it has a different structure than that of 2'-fucosyllactose (2'-FL), even though they have the same monosaccharide composition. In vitro prebiotic experiments were conducted to evaluate the differences in the utilization of three selected carbohydrates by fourteen bacterial strains. In comparison with 2'-FL, GFG could be utilized by more beneficial bacteria, leading to generate more short-chain fatty acids. Moreover, GFG could not promote the proliferation of Escherichia coli. This work describes a novel fucosylated oligosaccharide and its preparation method, and the obtained trisaccharide may serve as a promising candidate for fucosylated human milk oligosaccharides.

Biopharmaceutical applications of microbial polysaccharides as materials: A review

Biological characteristics of natural polymers make microbial polysaccharides an excellent choice for biopharmaceuticals. Due to its easy purifying procedure and high production efficiency, it is capable of resolving the existing application issues associated with some plant and animal polysaccharides. Furthermore, microbial polysaccharides are recognized as prospective substitutes for these polysaccharides based on the search for eco-friendly chemicals. In this review, the microstructure and properties of microbial polysaccharides are utilized to highlight their characteristics and potential medical applications. From the standpoint of pathogenic processes, in-depth explanations are provided on the effects of microbial polysaccharides as active ingredients in the treatment of human diseases, anti-aging, and drug delivery. In addition, the scholarly developments and commercial applications of microbial polysaccharides as medical raw materials are also discussed. The conclusion is that understanding the use of microbial polysaccharides in biopharmaceuticals is essential for the future development of pharmacology and therapeutic medicine.

Cost-Efficient Production of the Sphingan WL Gum by Sphingomonas sp. WG Using Molasses and Sucrose as the Carbon Sources

The polysaccharide WL gum is produced by the marine microorganism Sphingomonas sp. WG and presents great commercial utility potential in many industries especially in oil industries. However, the high fermentation cost limits its wide application. Therefore, an efficient production system at a lower cost was established using beet molasses to partially replace the commonly used carbon sources. Four different molasses were screened and their composition was investigated. One-factor design and RSM statistical analysis were employed to optimize the WL gum fermentation medium. The effects of molasses on the rheological properties and gene expression of WL gum were also investigated. The results showed that the pretreated beet molasses generated both high broth viscosity and WL gum production (12.94 Pa·s and 11.16 g/L). Heavy metal ions and ash were found to be the key factors in unpretreated and pretreated molasses affecting WL production. The cost-efficient production medium contained (g/L): sucrose 61.79, molasses 9.95, yeast extract 1.23, K₂HPO₄ 1, MgSO₄ 0.1, ZnSO₄ 0.1 and the WL gum production reached 40.25 ± 1.15 g/L. The WL gum product WL-molasses showed the higher apparent viscosity, and viscous modulus and elastic modulus than WL-sucrose and WL-mix, which might be related to its highest molecular mass. The higher expressional level of genes such as pgm, ugp, ugd, rmlA, welS, and welG in WL gum synthesis in the mixed carbon source medium caused the high production and broth viscosity. This work provided a cost-efficient method for WL gum production.

Whole-crop biorefinery of corn biomass for pullulan production by Aureobasidium pullulans

In the present study, corn starch, cob, and straw were biorefined and used as feedstocks for the production of pullulan. The titer and molecular weight (Mw) of pullulan significantly decreased when corn cob and straw hydrolysates were utilized by the parental strain Aureobasidium pullulans CCTCC M 2012259 (PS). Based on adaptive laboratory evolution of PS, an evolved strain A. pullulans EV6 with strong adaptability to the whole corn biomass hydrolysate and high capability of pullulan biosynthesis was screened. Batch pullulan fermentation results indicated that EV6 produced an increased titer of pullulan with a higher Mw than PS. The underlying reasons for these increases were revealed by assaying key enzymes activities and measuring intracellular uridine diphosphate glucose levels. Subsequently, whole-crop biorefinery of corn biomass was conducted, and the results confirmed that whole corn crop has immense potential for efficient pullulan production.

Microbial exopolysaccharides-β-glucans-as promising postbiotic candidates in vaccine adjuvants

The urgent task of creating new, enhanced adjuvants is closely related to our comprehension of their mechanisms of action. A few adjuvants have shown sufficient efficacy and low toxicity to be allowed for use in human vaccines, despite the fact that they have a long history and an important function. Adjuvants have long been used without a clear understanding of how precisely they augment the immune response. The rational production of stronger and safer adjuvants has been impeded by this lack of information, which necessitates more mechanistic research to support the development of vaccines. Carbohydrate structures-polygalactans, fructans, β-D-glucans, α-D-glucans, D-galactose, and D-glucose-are desirable candidates for the creation of vaccine adjuvants and immunomodulators because they serve important functions in nature and are often biocompatible, safe, and well tolerated. In this review, we have discussed recent advances in microbial-derived carbohydrate-based adjuvants, their immunostimulatory activity, and the implications of this for vaccine development, along with the critical view on the microbial sources, chemical composition, and biosynthetic pathways.

Sustainable Exopolysaccharide Production by Rhizobium viscosum CECT908 Using Corn Steep Liquor and Sugarcane Molasses as Sole Substrates

Microbial exopolysaccharides (EPS) are promising alternatives to synthetic polymers in a variety of applications. Their high production costs, however, limit their use despite their outstanding properties. The use of low-cost substrates such as agro-industrial wastes in their production, can help to boost their market competitiveness. In this work, an alternative low-cost culture medium (CSLM) was developed for EPS production by Rhizobium viscosum CECT908, containing sugarcane molasses (60 g/L) and corn steep liquor (10 mL/L) as sole ingredients. This medium allowed the production of 6.1 ± 0.2 g EPS/L, twice the amount produced in the standard medium (Syn), whose main ingredients were glucose and yeast extract. This is the first report of EPS production by R. viscosum using agro-industrial residues as sole substrates. EPS_CSLM and EPS_Syn exhibited a similar carbohydrate composition, mainly 4-linked galactose, glucose and mannuronic acid. Although both EPS showed a good fit to the Herschel-Bulkley model, EPS_CSLM displayed a higher yield stress and flow consistency index when compared with EPS_Syn, due to its higher apparent viscosity. EPS_CSLM demonstrated its potential use in Microbial Enhanced Oil Recovery by enabling the recovery of nearly 50% of the trapped oil in sand-pack column experiments using a heavy crude oil.

Anianabacter salinae gen. nov., sp. nov. ASV31T, a Facultative Alkaliphilic and Extremely Halotolerant Bacterium Isolated from Brine of a Millennial Continental Saltern

During a prokaryotic diversity study in Añana Salt Valley, a new Rhodobacteraceae member, designated ASV31T, was isolated from Santa Engracia spring water. It was extremely halotolerant, tolerating up to 23% NaCl, and facultatively alkaliphilic, growing at pH 6.5–9.5 (optimum at 7.0–9.5). The isolate was a Gram-negative, rod-shaped, aerobic and non-motile bacterium that formed beige-to-pink colonies on marine agar. According to a 16S rRNA gene-based phylogenetic analysis, strain ASV31T forms a distinct branch of the family Rhodobacteraceae, with Thioclava pacifica DSM 10166T being its closest type strain (95.3%). This was confirmed with a phylogenomic tree and the values of ANI (73.9%), dDDH (19.3%), AAI (63.5%) and POCP (56.0%), which were below the genus/species level boundary. Additionally, an ability to degrade aromatic compounds and biosynthesise secondary metabolites was suggested by the genome of strain ASV31T. Distinguishing fatty acid profiles and polar lipid content were also observed. The genome size was 3.6 Mbp, with a DNA G+C content of 65.7%. Based on the data obtained, it was considered that strain ASV31T (=CECT 30309T = LMG 32242T) represents a new species of a new genus in the family Rhodobacteraceae, for which the name Anianabacter salinae gen. nov., sp. nov. is proposed.

The potential use of Zymomonas mobilis for the food industry

Zymomonas mobilis is a gram-negative facultative anaerobic spore, which is generally recognized as a safe. As a promising ethanologenic organism for large-scale bio-ethanol production, Z. mobilis has also shown a good application prospect in food processing and food additive synthesis for its unique physiological characteristics and excellent industrial characteristics. It not only has obvious advantages in food processing and becomes the biorefinery chassis cell for food additives, but also has a certain healthcare effect on human health. Until to now, most of the research is still in theory and laboratory scale, and further research is also needed to achieve industrial production. This review summarized the physiological characteristics and advantages of Z. mobilis in food industry for the first time and further expounds its research status in food industry from three aspects of food additive synthesis, fermentation applications, and prebiotic efficacy, it will provide a theoretical basis for its development and applications in food industry. This review also discussed the shortcomings of its practical applications in the current food industry, and explored other ways to broaden the applications of Z. mobilis in the food industry, to promote its applications in food processing.

Exopolysaccharides from marine microbes with prowess for environment cleanup

A variety of both small and large biologically intriguing compounds can be found abundantly in the marine environment. Researchers are particularly interested in marine bacteria because they can produce classes of bioactive secondary metabolites that are structurally diverse. The main secondary metabolites produced by marine bacteria are regarded as steroids, alkaloids, peptides, terpenoids, biopolymers, and polyketides. The global urbanization leads to the increased use of organic pollutants that are both persistent and toxic for humans, other life forms and tend to biomagnified in environment. The issue can be addressed, by using marine microbial biopolymers with ability for increased bioremediation. Amongst biopolymers, the exopolysaccharides (EPS) are the most prominent under adverse environmental stress conditions. The present review emphasizes the use of EPS as a bio-flocculent for wastewater treatment, as an adsorbent for the removal of textile dye and heavy metals from industrial effluents. The biofilm-forming ability of EPS helps with soil reclamation and reduces soil erosion. EPS are an obvious choice being environmentally friendly and cost-effective in processes for developing sustainable technology. However, a better understanding of EPS biosynthetic pathways and further developing novel sustainable technologies is desirable and certainly will pave the way for efficient usage of EPS for environment cleanup.

Characterization and protective effect against ultraviolet radiation of a novel exopolysaccharide from Bacillus marcorestinctum QDR3-1

Although exopolysaccharide (EPS) has been applied to various fields, EPS for UVR-mediated oxidative stress repair still needs further exploration. In this study, a novel EPS was isolated from the fermentation medium of Bacillus sp. QDR3-1 and its yield was 4.8 g/L (pH 8.0, 12 % glucose, 30 °C and 6 % NaCl). The pure fraction (named EPS-M1) was purified by DEAE-cellulose and Sephadex G-100 column. EPS-M1 was a heteropolysaccharide composed of Man, Glc, Gal, and Fuc with a molecular weight of 33.8 kDa. Scanning electron microscopy (SEM) observed a rough surface and reticular structure of EPS-M1, and EPS-M1 formed spherical aggregates in aqueous solution observed in atomic force microscopy (AFM). Thermal analysis revealed that the degradation temperature of EPS-M1 was 306 °C. Moreover, methylation and NMR analysis determined that EPS-M1 was consisted of →3)-Manp-(1→, →2,6)-Manp-(1→, →4,6)-Glcp-(1→, →3)-Glcp-(1→, →4)-Galp-(1→, →4)-Fucp-(1→, and T-Manp-(1→. Furthermore, the cytotoxicity and the repair ability of UVR-mediated cell damage of EPS-M1 were studied with L929 cells. The results showed that EPS-M1 had good biocompatibility and it could mitigate UVR-mediated cell damage by regulating the levels of cellular reactive oxygen species (ROS), depolarization of mitochondrial membrane potential (MMP) and Caspase-3/7 activity. Overall, the structure analysis and the protective effects of EPS against L929 cells exposed to UVR provided an experimental basis for EPS in practical applications.

Potential Applications of an Exopolysaccharide Produced by Bacillus xiamenensis RT6 Isolated from an Acidic Environment

The Bacillus xiamenensis RT6 strain was isolated and identified by morphological, biochemical and molecular tests from an extreme acidic environment, Rio Tinto (Huelva). Optimisation tests for exopolysaccharide (EPS) production in different culture media determined that the best medium was a minimal medium with glucose as the only carbon source. The exopolymer (EPS_t) produced by the strain was isolated and characterised using different techniques (GC-MS, HPLC/MSMS, ATR-FTIR, TGA, DSC). The molecular weight of EPS_t was estimated. The results showed that the average molecular weight of EPS_t was approximately 2.71 × 10⁴ Da and was made up of a heteropolysaccharide composed of glucose (60%), mannose (20%) and galactose (20%). The EPS_t showed antioxidant capabilities that significantly improved cell viability. Metal chelation determined that EPS_t could reduce the concentration of transition metals such as iron at the highest concentrations tested. Finally, the emulsification study showed that EPS_t was able to emulsify different natural polysaccharide oils, reaching up to an 80% efficiency (olive and sesame oil), and was a good candidate for the substitution of the most polluting emulsifiers. The EPS_t was found to be suitable for pharmaceutical and industrial applications.

A Comprehensive Review of Biodegradable Polymer-Based Films and Coatings and Their Food Packaging Applications

Food sectors are facing issues as a result of food scarcity, which is exacerbated by rising populations and demand for food. Food is ordinarily wrapped and packaged using petroleum-based plastics such as polyethylene, polyvinyl chloride, and others. However, the excessive use of these polymers has environmental and health risks. As a result, much research is currently focused on the use of bio-based materials for food packaging. Biodegradable polymers that are compatible with food products are used to make edible packaging materials. These can be ingested with food and provide consumers with additional health benefits. Recent research has shifted its focus to multilayer coatings and films-based food packaging, which can provide a material with additional distinct features. The aim of this review article is to investigate the properties and applications of several bio-based polymers in food packaging. The several types of edible film and coating production technologies are also covered separately. Furthermore, the use of edible films and coatings in the food industry has been examined, and their advantages over traditional materials are also discussed.

An update on biomaterials as microneedle matrixes for biomedical applications

Microneedles (MNs) have been developed for various applications such as drug delivery, cosmetics, diagnosis, and biosensing. To meet the requirements of MNs used in these areas, numerous materials have been used for the fabrication of MNs. However, MNs will be exposed to skin tissues after piercing the stratum corneum barrier. Thus, it is necessary to ensure that the matrix materials of MNs have the characteristics of low toxicity, good biocompatibility, biodegradability, and sufficient mechanical properties for clinical application. In this review, the matrix materials currently used for preparing MNs are summarized and reviewed in terms of these factors. In addition, MN products used on the market and their applications are summarized in the end. This work may provide some basic information to researchers in the selection of MN matrix materials and in developing new materials.