Exopolysaccharide Research Articles

Guardians of the Gut: Harnessing the Power of Probiotic Microbiota and Their Exopolysaccharides to Mitigate Heavy Metal Toxicity in Human for Better Health.

Heavy metal pollution is a significant global health concern, posing risks to both the environment and human health. Exposure to heavy metals happens through various channels like contaminated water, food, air, and workplaces, resulting in severe health implications. Heavy metals also disrupt the gut's microbial balance, leading to dysbiosis characterized by a decrease in beneficial microorganisms and proliferation in harmful ones, ultimately exacerbating health problems. Probiotic microorganisms have demonstrated their ability to adsorb and sequester heavy metals, while their exopolysaccharides (EPS) exhibit chelating properties, aiding in mitigating heavy metal toxicity. These beneficial microorganisms aid in restoring gut integrity through processes like biosorption, bioaccumulation, and biotransformation of heavy metals. Incorporating probiotic strains with high affinity for heavy metals into functional foods and supplements presents a practical approach to mitigating heavy metal toxicity while enhancing gut health. Utilizing probiotic microbiota and their exopolysaccharides to address heavy metal toxicity offers a novel method for improving human health through modulation of the gut microbiome. By combining probiotics and exopolysaccharides, a distinctive strategy emerges for mitigating heavy metal toxicity, highlighting promising avenues for therapeutic interventions and health improvements. Further exploration in this domain could lead to groundbreaking therapies and preventive measures, underscoring probiotic microbiota and exopolysaccharides as natural and environmentally friendly solutions to heavy metal toxicity. This, in turn, could enhance public health by safeguarding the gut from environmental contaminants.

OPTIMIZATION OF PHYSIOLOGICAL PARAMETERS FOR EXOPOLYSACCHARIDE PRODUCTION USING Pseudomonas aeruginosa MSSRFV42

Exopolysaccharides (EPS) are long-chain polysaccharides containing branched, repeating units of sugars or sugar derivatives such as glucose, fructose, mannose and galactose etc, which are secreted into their surrounding environment during the bacterial growth. Due to their unique properties and vast array of application, isolation and study of new EPS producing microbes is highly concerned issue. In the present study potent exopolysaccharide producing AB4 bacteria (Pseudomonas aeruginosa MSSRFV42) which was previously isolated and screened from marine sample was used. To increase the yield of exopolysaccharide significant physiological parameter were determined Submerged fermentation at pH 10 and temperature of 300C gave maximum yield of EPS after 72 hrs incubation using 1% inoculums in media containing 3.5% NaCl. Outcome of this study will definitely contribute in the elucidation components of AB4 EPS in various industries . Keywords: EPS, Pseudomonas aeruginosa, Optimization

The Cd resistant mechanism of Proteus mirabilis Ch8 through immobilizing and detoxifying

Cadmium (Cd) pollution is a serious global environmental problem, which requires a global concern and practical solutions. Microbial remediation has received widespread attention owing to advantages, such as environmental friendliness and soil amelioration. However, Cd toxicity also severely deteriorates the remediation performance of functional microorganisms. Analyzing the mechanism of bacterial resistance to Cd stress will be beneficial for the application of Cd remediation. In this study, the bacteria strain, up to 1400 mg/L Cd resistance, was employed and identified as Proteus mirabilis Ch8 (Ch8) through whole genome sequence analyses. The results indicated that the multiple pathways of immobilizing and detoxifying Cd maintained the growth of Ch8 under Cd stress, which also possessed high Cd extracellular adsorption. Firstly, the changes in surface morphology and functional groups of Ch8 cells were observed under different Cd conditions through SEM-EDS and FTIR analyses. Under 100 mg/L Cd, Ch8 cells exhibited aggregation and less flagella; the Cd biosorption of Ch8 was predominately by secreting exopolysaccharides (EPS) and no significant change of functional groups. Under 500 mg/L Cd, Ch8 were present irregular polymers on the cell surface, some cells with wrapping around; the Cd biosorption capacity exhibited outstanding effects (38.80 mg/g), which was mainly immobilizing Cd by secreting and interacting with EPS. Then, Ch8 also significantly enhanced the antioxidant enzyme activity and the antioxidant substance content under different Cd conditions. The activities of SOD and CAT, GSH content of Ch8 under 500 mg/L Cd were significantly increased by 245.47%, 179.52%, and 241.81%, compared to normal condition. Additionally, Ch8 significantly induced the expression of Acr A and Tol C (the resistance-nodulation-division (RND) efflux pump), and some antioxidant genes (SodB, SodC, and Tpx) to reduce Cd damage. In particular, the markedly higher expression levels of SodB under Cd stress. The mechanism of Ch8 lays a foundation for its application in solving soil remediation.

Isolation, structural characterization and immunomodulatory activity on RAW264.7 cells of a novel exopolysaccharide of Dictyophora rubrovalvata

Fungal polysaccharides have been explored by many for both structural studies and biological activities, but few studies have been done on the extracellular polysaccharides of Dictyophora rubrovalvata, so a new exopolysaccharide was isolated from Dictyophora rubrovalvata and its structure and its immunological activity were investigated. The crude exopolysaccharide (EPS) was purified by DEAE52 cellulose and Sephadex G-200 to obtain a new acidic polysaccharide (DR-EPS). DR-EPS (2.66 × 103 kDa) was consisted mainly of mannose, glucose, galactose and glucuronic acid with a molar ratio of 1: 0.86: 0.20: 0.01. In addition, DR-EPS increased the phagocytic activity of RAW264.7 cells up to 2.67 times of the blank control group. DR-EPS improved intracellular nucleic acid and glycogen metabolism as observed by AO and PAS staining. DR-EPS(40 μg/mL) promoted NO production up to 30.66 μmol, enhanced acid phosphatase (ACP) and superoxide dismutase (SOD) activities, with activity maxima of 660 U/gprot and 96.27 U/mgprot, respectively, and DR-EPS (160 μg / mL) significantly increased the lysozyme content as 2.73 times of the control group. The good immunological activity of extracellular polysaccharides of Dictyophora rubrovalvata provides directions for the use of fermentation broths.

Biomedical and therapeutic potential of marine-derived Pseudomonas sp. strain AHG22 exopolysaccharide: A novel bioactive microbial metabolite

Abstract Microbial exopolysaccharides (EPSs) are gaining interest as alternatives to chemical antioxidants and pharmaceuticals. This study mines the promising biomedical and antimicrobial potential of a marine bacterium, a prolific EPS producer, isolated from the Red Sea. Pseudomonas sp. strain AHG22 generated an EPS weighing 6.98 g·L−1, coded EPSF8, subjected to FT-IR and HPLC chemical analysis. EPSF8 was then investigated for antioxidant assessment by 2,2-diphenyl-1-picrylhydrazyl (DPPH), H2O2, ABTS˙ + , nitric oxide, total antioxidant capacity (TAC), and ferric reducing antioxidant power (FRAP). EPSF8 had an IC50 of 46.99 μg·mL−1 in the DPPH antioxidant assay and antioxidant capacities of 219.45 μg·mg−1 ascorbic acid equivalent (AAE) in the TAC assay and 54.15 μg·mg−1 AAE in the FRAP assay. The in vitro anti-inflammatory effect of EPSF8 was tested against 5-lipoxygenase (5-LOX) and cyclooxygenase-2 (COX-2) enzymes and compared with the drugs ibuprofen and celecoxib used as controls. The IC50 values of 5-LOX, COX-2, ibuprofen, and celecoxib were found to be 14.82, 15.49, 1.5, and 0.28 μg·mL−1, respectively. Additionally, EPSF8 revealed antidiabetic activity toward α-amylase and α-glucosidase, and the IC50 values were 93.1 and 127.28 μg·mL−1, compared to those of acarbose (50.93 and 4.13 μg·mL−1, respectively). Anti-obesity activity of EPSF8 by lipase inhibition revealed IC50 = 56.12 μg·mL−1 compared to orlistat (IC50 = 20.08 μg·mL−1) as a control. EPSF8 displayed antibiofilm and bactericidal activity against Gram-positive (G +ve) and Gram-negative (G −ve) ATCC pathogenic bacterial strains. It had a minimum bactericidal concentration/minimum inhibitory concentration ratio ≤2, indicating a broad bactericidal spectrum. Furthermore, EPSF8 is evidenced to have a promising anti-butyrylcholinesterase activity for the control of Alzheimer’s disease. The findings of the present analysis suggest that the isolated Pseudomonas sp. strain AHG22 EPS can potentially be explored as a promising green therapeutic compound.

Molecular weight control of poly-γ-glutamic acid reveals novel insights into extracellular polymeric substance synthesis in Bacillus licheniformis

BackgroundThe structural diversity of extracellular polymeric substances produced by microorganisms is attracting particular attention. Poly-gamma-glutamic acid (γ-PGA) is a widely studied extracellular polymeric substance from Bacillus species. The function of γ-PGA varies with its molecular weight (Mw).ResultsHerein, different endogenous promoters in Bacillus licheniformis were selected to regulate the expression levels of pgdS, resulting in the formation of γ-PGA with Mw values ranging from 1.61 × 103 to 2.03 × 104 kDa. The yields of γ-PGA and exopolysaccharides (EPS) both increased in the pgdS engineered strain with the lowest Mw and viscosity, in which the EPS content was almost tenfold higher than that of the wild-type strain. Subsequently, the compositions of EPS from the pgdS engineered strain also changed. Metabolomics and RT-qPCR further revealed that improving the transportation efficiency of EPS and the regulation of carbon flow of monosaccharide synthesis could affect the EPS yield.ConclusionsHere, we present a novel insight that increased pgdS expression led to the degradation of γ-PGA Mw and changes in EPS composition, thereby stimulating EPS and γ-PGA production. The results indicated a close relationship between γ-PGA and EPS in B. licheniformis and provided an effective strategy for the controlled synthesis of extracellular polymeric substances.

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

Bifidobacteria are a prominent type of bacteria that have garnered significant research attention for their exceptional probiotic properties and capacity to produce exopolysaccharides (EPSs). These compounds exhibit diverse physical, chemical, and biological characteristics, prompting numerous investigations into their potential applications. Researchers have noted their beneficial effects as immune modulators within the host's body across various industries. Extensive research has been conducted on the immunomodulatory effects of bifidobacteria-derived EPSs, with emerging engineering strategies aimed at enhancing their immune-modulating capabilities. Understanding the structure, physicochemical properties, and biological activities of these compounds is crucial for their effective utilization across different industries. Our review encompassed numerous studies exploring Bifidobacterium and its metabolites, including EPSs, across various sectors, drawing from diverse databases. The distinctive properties of EPSs have spurred investigations into their applications, revealing their potential to bolster the immune system, combat inflammation, and treat various ailments. Additionally, these compounds possess antioxidant and antimicrobial properties, making them suitable for incorporation into a range of products spanning food, health, and medicine.

Burn Wound Healing Abilities of a Uronic Acid Containing Exopolysaccharide Produced by the Marine Bacterium Halomonas malpeensis YU-PRIM-29T.

Bacterial exopolysaccharides (EPS) are an emerging class of biopolymers with extensive applications in different fields due to their versatile physico-chemical and biological properties. The role of EPS in healing of different wound types is gaining interest in the tissue engineering sector. Burn is one of the devitalizing injuries that causes greater physical harm and can be fatal. Appropriate treatment modalities have to be followed for faster healing outcomes and to minimize the risk. In this study, a bacterial EPS (EPS-H29) from the marine bacterium Halomonas malpeensis YU-PRIM-29T was used to treat the burn wound in vivo. The biochemical and structural characterizations of EPS-H29 were carried out using standard methods. In addition, FE-SEM, conformational, rheological, and HP-GPC analyses were carried out. In vitro biocompatibility of EPS-H29 was studied in human dermal fibroblasts (HDFs) and keratinocytes (HaCaT). Scratch assay was used to study the wound healing in vitro. For in vivo evaluation, burn wound (second-degree) was created on Wistar albino rats and treated with EPS-H29 along with appropriate control groups. The total sugar and protein contents of EPS-H29 were 72.0 ± 1.4% and 4.0 ± 0.5%, respectively, with a molecular weight of 5.2 × 105Da. The lyophilized samples exhibited porous surface features, and in solution, it showed triple helical conformation and shear thickening behavior. In vitro cell-based assays showed biocompatibility of EPS-H29 up to 200μg/mL concentration. At a concentration up to 50μg/mL, EPS-H29 promoted cell proliferation. Significant increase in the HDF cell migration was evident with EPS-H29 (15μg/mL) treatment in vitro and induced significantly higher (p ≤ 0.0001) closure of the scratch area (90.3 ± 1.1%), compared to the control (84.3 ± 1.3%) at 24h. Enhanced expression of Ki-67 was associated with the cell proliferative activities of EPS-H29. The animals treated with EPS-H29 showed improved healing of burn wounds with significantly higher wound contraction rate (80.6 ± 9.4%) compared to the positive control (54.6 ± 8.0%) and untreated group (49.2 ± 3.7%) with histopathological evidence of epidermal tissue formation at 15days of treatment. These results demonstrate the biocompatibility and burn wound healing capability of EPS-H29 and its potential as an effective topical agent for the burn wound care.

Limosilactobacillus reuteri L26 BiocenolTM and its exopolysaccharide: Their influence onrotavirus-induced immune molecules inenterocyte-like cells.

This study aimed toevaluate the immunomodulatory effect ofthe probiotic Limosilactobacillus reuteri L26 BiocenolTM (L26) and its purified exopolysaccharide (EPS) with respect toantiviral innate immune response. Inour experiment, weused porcine epithelial IPEC-J2 cells asamodel ofthe intestinal barrier inahomologous infection byporcine RotavirusAstrain OSU6 (RVA). The production ofselected molecules ofnon-specific humoral immunity was evaluated atthe mRNA level. The EPS alone significantly increased the level ofinterferon λ3 (IFN-λ3) mRNA inthe non-infected IPEC-J2 cells (P<0.001). Wealso tested whether the treatment ofIPEC-J2 cells byL26 orEPS influences the replication ofRVA byvirus titration and real-time PCR. Wefound that apre-treatment incombination with subsequent continuous stimulation has noinfluence onthe RVA replication. However, both treatments significantly decreased the RVA-induced production ofIFN-λ3 (P<0.05) and the "SOS" cytokine interleukin6 (IL-6; P<0.01), already atthe transcription level. Inaddition, the EPS treatment resulted insignificantly increased IL-10 mRNA inthe RVA-infected cells. Insummary, weassume animmunoregulatory potential ofL.reuteri L26 BiocenolTM and its EPS inthe local intestinal antiviral immune response.

Review on microbial production of exopolysaccharides and its applications

Exopolysaccharides (EPS) are bio-molecules produced by variety of microorganisms by both eukaryotes and prokaryotic. EPS are high molecular weight molecules available in both homopolysaccharide and heteropolysaccharide. Plants are the primary source of exopolysaccharides (EPS); however, microbiological EPS have a diverse range of structures and functions that enable them to endure harsh environmental conditions. Studying the structure and composition of exopolysaccharides is crucial for understanding their beneficial functions and potential applications in different fields such as food, dairy, medical, pharmaceutical, cosmetics and other industries. This review briefly describes how extremities trigger microbes to produce EPS with unique properties. In addition, it covers optimization and strain improvement methods to increase the productivity of microbes, extraction and purification methods. Similarities and differences of solid-state fermentation and submerged fermentation for EPS production from Bacteria and Fungi are sighted in this review. Applications of EPS in different fields owing to their various physicochemical properties are also discussed in this review. This review provides explanations with respect to microbial habitats, fermentation scales, purification methods and recent research on their potential applications.

Physiological properties evaluation and exopolysaccharide biosynthesis of Limosilactobacillus fermentum JL-2 from Chinese traditional fermented dairy product based on genomic insight

Limosilactobacillus fermentum JL-2 with high production of exopolysaccharide (EPS) was screened from the traditional fermented dairy product in Xinjiang district (China) in our previous work. In this study, the whole genome of L. fermentum JL-2 was sequenced and the genomic information and function were studied to excavate its genotype, safety and probiotic properties. The safety evaluation in vitro showed that L. fermentum JL-2 was not hemolytic, sensitive to common antibiotics, and it had a weak biogenic amine production capacity. The genes related to EPS biosynthesis and their relationship with EPS production were discussed. The EPS production of L. fermentum JL-2 was 553.6 mg/L. The genome of L. fermentum JL-2 consisted of a circular 1.98 Mbp chromosome. A variety of genes related to probiotic properties such as acid tolerance, bile salt tolerance, adhesion to gut mucosa and environmental stress resistance were contained. A complete EPS gene cluster was found in the genome of L. fermentum JL-2, and the genes related to EPS biosynthesis such as epsA and epsB were found in L. fermentum JL-2. It is worth noting that EPS biosynthesis protein (gene0099) seemed to play a key role in the EPS synthesis of L. fermentum JL-2. These results revealed the potential of L. fermentum JL-2 as a probiotic at the gene level. Therefore, this study laid a theoretical foundation for further research into its potential probiotic function and its application in practice.

The optimization of in situ exopolysaccharides production in Lactobacillus helveticus MB2-1 fermented milk and its functional characteristics in vitro

In order to improve the in situ exopolysaccharides (EPS) production of Lactobacillus helveticus MB2-1 fermented milk and explore its functional characteristics, the production optimization conditions, structural characteristics of fermented milk, emulsifying properties, antioxidant, and antibiofilm activities of in situ produced EPS were investigated. The fermentation conditions were optimized using response surface methodology. When the optimal temperature was 37 °C for 8.0 h with 7.0% w/w of inoculum size, the EPS yield could be up to 340 mg L−1. The L. helveticus MB2-1 fermented milk presented better gel structure than the control under the optimized conditions. The in situ produced EPS presented fine emulsifying properties, exhibited potent antioxidant activities as well as obvious antibiofilm activities against foodborne biofilm-forming pathogens. These findings demonstrated that in situ produced EPS in L. helveticus MB2-1 fermented milk has multiple functional qualities and can be a potent ingredient for supplementation and fortification of functional food products.

Effects of priming glycosyltransferase genes cps 2E and cps 4E on the exopolysaccharide biosynthesis by Lactiplantibacillus plantarum YM-4-3 strain

Microbial exopolysaccharides (EPS) have various physiological functions such as antioxidant, anti-tumor, cholesterol lowering, and immune regulation. However, improving traditional fermentation conditions to increase the production of EPS from Lactiplantibacillus plantarum (L. plantarum) is limited. In this study, we aimed to better improve EPS production and physiological functions of L. plantarum YM-4-3 strain by overexpressing and knocking out the priming glycosyltransferase genes cps 2E and cps 4E for the first time. As a result, the EPS production of the overexpression strain was 30.15 %, 26.84 % and 36.29 % higher than WT, respectively. The EPS production of the knockout strain was significantly lower than that of the WT. At the same time, transcriptome data showed that the gene expression levels of each experimental strain had changed. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways found that the glycolysis/gluconeogenesis pathway had the highest gene enrichment in the metabolic pathway. The monosaccharide components of the EPS of each experimental strain were different from those of the WT and the EPS of the experimental strain showed stronger activity against oxidation. In conclusion, this study contributes to the efficient production and application of L. plantarum EPS and helps to understand the mechanism of EPS regulation in L. plantarum.

Submerged production of mycelium biomass and bioactive compounds from P. ostreatus in a controlled fermentation medium

Pleurotus ostreatus is commonly consumed mushroom species around the world due to its unique taste, flavor, and presence of biologically active compounds. The current study investigated the biological activities of P. ostreatus in submerged cultivation. Cultivation factors such as pH, temperature, inoculum density, and cultivation time with different carbon and nitrogen sources were optimized to obtain a high yield of biomass and exopolysaccharides (EPSs). The maximum biomass and EPS obtained were 24.66 ± 0.2 g/L and 4.8 ± 0.1 g/L respectively. The protein content and total phenolic content (TPC) were achieved as 0.936 ± 0.005 g/L and 16.484 ± 0.06 mg GAE/g respectively at 12th day of cultivation. Antioxidant activity of P. ostreatus was obtained as 49.59 ± 1.09%. Under optimized conditions, the P. ostreatus was also cultivated in a rotary bed reactor (RBR). Furthermore, different kinetic models were studied to observe the growth behaviour of mycelium biomass. The best fit was obtained for the contois model, which gave the maximum specific growth rate (µmax, hr−1) of 0.0235 hr−1 and R2 value of 0.976.

Genomic characterization and probiotic potential assessment of an exopolysaccharide-producing strain Pediococcus pentosaceus LL-07 isolated from fermented meat

BackgroundThe genomic information available for Pediococcus pentosaceus is primarily derived from fermented fruits and vegetables, with less information available from fermented meat. P. pentosaceus LL-07, a strain isolated from fermented meat, has the capability of producing exopolysaccharides (EPS). To assess the probiotic attributes of P. pentosaceus LL-07, we conducted whole-genome sequencing (WGS) using the PacBio SequelIIe and Illumina MiSeq platforms, followed by in vitro experiments to explore its probiotic potential.ResultsThe genome size of P. pentosaceus LL-07 is 1,782,685 bp, comprising a circular chromosome and a circular plasmid. Our investigation revealed the absence of a CRISPR/Cas system. Sugar fermentation experiments demonstrated the characteristics of carbohydrate metabolism. P. pentosaceus LL-07 contains an EPS synthesis gene cluster consisting of 13 genes, which is different from the currently known gene cluster structure. NO genes associated with hemolysis or toxin synthesis were detected. Additionally, eighty-six genes related to antibiotic resistance were identified but not present in the prophage, transposon or plasmid. In vitro experiments demonstrated that P. pentosaceus LL-07 was comparable to the reference strain P. pentosaceus ATCC25745 in terms of tolerance to artificial digestive juice and bile, autoaggregation and antioxidation, and provided corresponding genomic evidence.ConclusionThis study confirmed the safety and probiotic properties of P. pentosaceus LL-07 via complete genome and phenotype analysis, supporting its characterization as a potential probiotic candidate.

Characterization and optimization of exopolysaccharide extracted from a newly isolated halotolerant cyanobacterium, Acaryochloris Al-Azhar MNE ON864448.1 with antiviral activity

Several antiviral agents lost their efficacy due to their severe side effects and virus mutations. This study aimed to identify and optimize the conditions for exopolysaccharide (EPS) production from a newly isolated cyanobacterium, Acaryochloris Al-Azhar MNE ON864448.1, besides exploring its antiviral activity. The cyanobacterial EPS was purified through DEAE-52 cellulose column with a final yield of 83.75%. Different analysis instruments were applied for EPS identification, including Fourier-transform infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA), and gas chromatographic-mass spectrometry (GC–MS). Plackett–Burman’s design demonstrated that working volume (X1), EDTA (X2), inoculum size (X3), CaCl2 (X4), and NaCl (X5) are the most important variables influencing EPS production. Central composite design (CCD) exhibited maximum EPS yield (9.27 mg/mL) at a working volume of 300 mL in a 1 L volumetric flask, EDTA 0.002 g/L, inoculum size 7%, CaCl2 0.046 g/L, and NaCl 20 g/L were applied. EPS showed potent antiviral activities at different stages of herpes simplex virus type-1 and 2 (HSV-1, HSV-2), adenovirus (ADV) and coxsackievirus (A16) infections. The highest half-maximal inhibitory concentration (IC50) (6.477 µg/mL) was recorded during HSV-1 internalization mechanism, while the lowest IC50 (0.005669 µg/mL) was recorded during coxsackievirus neutralization mechanism.

Inhibition of Carbon Steel Corrosion Using Dextran Derivatives in Circulating Cooling Water

Developing environmentally friendly and biodegradable corrosion inhibitors is an important research direction due to the toxicity and non-degradability of conventional carbon steel corrosion inhibitors added to circulating cooling water environments. Polysaccharides in EPSs (Exopolysaccharides) can be used as green corrosion inhibitors, but a low inhibition rate limits their practical application. Chemical modification is widely used to modify the functionality of polysaccharides by altering their physicochemical properties and structures, thereby enhancing or supplementing their functional characteristics. In this study, we employed chloroacetic acid as an esterifying agent to chemically modify Dextran and successfully synthesized a modified polysaccharide derivative with a substitution degree of 0.326. This derivative efficiently inhibited the corrosion of carbon steel in circulating cooling water environments. The carboxymethylated dextran (CM-Dextran) formed after synthesis could adsorb onto metal surfaces to form a protective film, thereby inhibiting metal surface dissolution reactions and exhibiting anodic corrosion inhibition properties. The experimental results showed that the corrosion inhibition efficiency of CM-Dextran after modification increased by up to 57.4%, with a maximum inhibition efficiency of 82.52% at a concentration of 4 mg/mL. This study provides new insights and opportunities for the development of environmentally friendly corrosion inhibitors derived from polysaccharides.

Exopolysaccharides isolated from fermented milk-associated lactic acid bacteria and applied to produce functional value-added probiotic yogurt

The current study aimed to isolate and characterize the lactic acid bacteria (LAB)-derived exopolysaccharide (EPS) and apply it to enhance yogurt's functional and technological quality. After screening and isolation of 52 different LAB strains from fermented milk products, Lactobacillus (L.) rhamnosus KF5, L. plantarum C182, Pediococcus (P.) acidilactici CCFM18, and Leuconostoc (Leu.) mesenteroides F27, with high EPS production yield, were nominated for further evaluation. EPS-derived strains were evaluated based on production yield, protein content, antioxidant activity, emulsification, and anti-inflammatory ability. After comparing isolated EPS samples, the Leu. mesenteroides F27 products were chosen in 3 concentrations (100, 250, and 500 mg EPS/L) to supplement the yogurt. EPS at all concentrations enhanced LAB growth, water-holding capacity, viscosity, and antioxidant activity. The electronic nose and tongue revealed that EPS did not affect the yogurt flavor profile. The confocal laser scanning microscopy showed a homogenously distributed protein and EPS network in the supplemented yogurt samples. However, in the rheology and consumer analysis, the 250 mg/L concentration showed better attributes, such as higher consistency, lower flow behavior, and a higher flavor score. Leu. mesenteroides F27-derived EPS could be used as a biological additive to enhance yogurt's technological and functional quality.

Isolation and Molecular Profiling of Halotolerant Plant Growth Promoting Rhizosphere Fungi from Salt affected Agroforestry Plantation

Soil salinity is a major abiotic stress that adversely affects plant growth, and productivity. About 20% of irrigated lands are affected by salinity worldwide; In India, there are 6.74 million hectares of salt-affected lands. Salt-tolerant Plant Growth Promoting (PGP) microorganisms can enhance the growth of plants in such salt-stressed areas. Therefore, this study aimed to investigate the diversity of beneficial fungal communities, screen for their ability to support plant growth, and evaluate the production of various essential compounds in view of plant growth in salt-stressed lands. A total of 68 fungal colonies were isolated from 5 different agroforestry plantation sites in Karur, Tamil Nadu, South India at quarterly intervals. The isolates were screened for sodium chloride (NaCl) tolerance (0%, 5%, 10%, 15%, and 20% concentration). A total of 7 isolates showed considerable salt tolerance and were tested qualitatively in-vitro, for PGP traits such as phosphate, potassium, and zinc solubilization, nitrogen fixation, hydrogen cyanide production, siderophore production, and ACC deaminase production. Finally, 5 isolates with maximum values for PGP properties under 20% NaCl concentration were tested for the quantity of Indole-3-Acetic Acid (IAA) and Exo-polysaccharide (EPS) production. All 5 isolates were identified up to the species level using 18S rRNA gene sequencing. To the best of our knowledge, this is the first report on isolating saline-tolerant PGP Fungi (PGPF) from the rhizosphere region of Casuarina equisetifolia and Eucalyptus camaldulensis in Karur, Tamil Nadu, India. In the future, the bioformulation of PGPF and its application will boost the cultivation of tree saplings in this salt affected regions.

Application of exopolysaccharides synthesized by Xanthomonas campestris in an efficient separation system of refractory chalcopyrite and molybdenite

Bacterial polysaccharides get an abundance of attention owing to their distinctive biological activity and promising applications. Recent research found that the specificity of the molecular structure of exopolysaccharides (EPS) can be used to accomplish selective regulation of the physicochemical properties of mineral surfaces. The development and application of novel microbial EPS as a flotation reagent for chalcopyrite and molybdenite separation possesses a promising development prospect. Consequently, we attempted to create effective and sustainable molybdenite depressants in this work by optimizing the strain's fermentation settings and identifying the molecular structure of the generated EPS. Fermentation condition tests revealed patterns of influence of fermentation parameters on EPS yield, the viscosity average molecular weight, and biomass during the fermentation process, and optimized the optimal fermentation conditions. Fourier transform infrared (FTIR), nuclear magnetic resonance (NMR), and ion chromatography (IC) analyses clarified the structure of the EPS in terms of monosaccharide composition, glycosidic bonding, and functional groups. Mixed mineral flotation tests proved that a low dosage of polysaccharide reagent (100 mg/L) at pH 10 effectively inhibited molybdenite and achieved separation targets of 21.96% Cu and 2.63% Mo in the concentrate, with separation efficiencies (SE) of 72.67% and 55.78% for Cu and Mo, respectively.