Production, characterization and bio-emulsifying activity of a novel thermostable exopolysaccharide produced by a marine strain of Rhodobacter johrii CDR-SL 7Cii

Preparation of Novel Marine Enterococcus faecium MSD8 Exopolysaccharide Ointment and In Vivo Evaluation of Its Impact on Cutaneous Wound Healing in Male Albino Rats

The current study describes the isolation of exopolysaccharide (EPS) producing lactic acid bacteria (LAB) from marine samples and testing different sugar additives with different proportions for enhanced EPS yield. The isolate MSD8 showed the most potential, yielding 200 mg/L of EPS after being cultivated at 37 °C for 48 h on de Man Rogosa and Sharpe medium (MRS) supplemented with 3% sucrose. The marine isolate MSD8 was identified as Enterococcus faecium with 99.58% probability using 16S rRNA gene sequencing. The obtained sequence was deposited in GenBank and assigned the accession number MW924065. The feature of MSD8-EPS was characterized by estimating the total carbohydrate content by UV-vis to be ~ 71%. The FTIR analysis further indicated the presence of characteristic bands of polysaccharide. The cytotoxicity of the produced MSD8-EPS was assessed using human skin fibroblasts (HSF). The IC50 was determined to be > 100 μg/mL, which signifies that MSD8-EPS is safe for skin application. The produced EPS was used to prepare a novel ointment, which was tested for wound healing ability in male albino rats. The ointment significantly (P ≤ 0.05) shortened the time needed for wound healing, as it successfully healed the wounds by 94.93% on the 7th day and completely (100%) healed the wound by the 12th day. In comparison, the control group was healed by 73.2% and 84.83%, respectively. The data confirm that the prepared ointment can safely be used for pharmaceutical wound care products.

Deciphering the molecular interaction of extracellular polymeric substances of a marine bacterium Pseudomonas furukawaii PPS-19 with petroleum hydrocarbons and development of bioadsorbent

Petroleum hydrocarbon contamination is a serious hazard to marine environments, affecting ecosystems and marine life. However, extracellular polymeric substances (EPS) of marine bacteria constituting various hydrophilic and hydrophobic functional groups sequester petroleum hydrocarbons (PHs). In this study, interaction of EPS of Pseudomonas furukawaii PPS-19 with PHs such as crude oil, n-dodecane, and pyrene and its impact on PHs adsorption was investigated. Protein component of EPS was increased after treatment with PHs. Red shift of UV-Vis spectra implied change in molecular structure of EPS. Functional groups of proteins (CO, NH2) and polysaccharides (C-C, C-OH, C-O-C) predominantly interacted with PHs. Interaction with PHs affected secondary structure of EPS. Change in binding energies of corresponding functionalities of C 1s, O 1s, and N 1s confirmed the interaction. Disruption of crystalline peaks led to increased pore size in EPS primarily due to the increase in surface electronegativity. Static quenching mechanism unveils formation of complex between fulvic acid of EPS and PHs. Relative expression of alg8 gene was significantly increased in the presence of n-dodecane (6.31 fold) (P < 0.05; One way ANOVA). n-dodecane and pyrene adsorption capacity of Immobilized EPS was significantly higher (356.5 and 338.2 mg g-1, respectively) (P < 0.001; One way ANOVA) than control. Adsorption rate fits into the pseudo-second-order kinetic model. This study establishes that interaction of PHs causes structural and physical changes in EPS and EPS could be used as an adsorbent material for the sequestration of PHs pollution.

Genomic and functional evaluation of exopolysaccharide produced by Liquorilactobacillus mali t6-52: technological implications

BACKGROUND

This study explores the biosynthesis, characteristics, and functional properties of exopolysaccharide produced by the strain Liquorilactobacillus mali T6-52. The strain demonstrated significant EPS production with a non-ropy phenotype.

RESULTS

The genomic analysis unveiled genes associated with EPS biosynthesis, shedding light on the mechanism behind EPS production. These genes suggest a robust EPS production mechanism, providing insights into the strain's adaptability and ecological niche. Chemical composition analysis identified the EPS as a homopolysaccharide primarily composed of glucose, confirming its dextran nature. Furthermore, it demonstrated notable functional properties, including antioxidant activity, fat absorption capacity, and emulsifying activity. Moreover, the EPS displayed promising cryoprotective activities, showing notable performance comparable to standard cryoprotective agents. The EPS concentration also demonstrated significant freeze-drying protective effects, presenting it as a potential alternative cryoprotectant for bacterial storage.

CONCLUSIONS

The functional properties of L. mali T6-52 EPS reveal promising opportunities across various industrial domains. The strain's safety profile, antioxidant prowess, and exceptional cryoprotective and freeze-drying characteristics position it as an asset in food processing and pharmaceuticals.

Unveiling the structure-emulsifying function relationship of truncated recombinant forms of the SA01-OmpA protein opens up a new vista in bioemulsifiers

The emulsifying ability of SA01-OmpA (outer membrane protein A from Acinetobacter sp. SA01) was found to be constrained by challenges like low production efficiency and high costs associated with protein recovery from E. coli inclusion bodies, as described in our previous study. The present study sought to benefit from the advantages of the targeted truncating of SA01-OmpA protein, taking into account the reduced propensity of protein expression as inclusion bodies and cytotoxicity. Here, the structure and activity relationship of two truncated recombinant forms of SA01-OmpA protein was unraveled through a hybrid approach based on experimental data and computational methodologies, representing an innovative bioemulsifier with advantageous emulsifying activity. The recombinant truncated SA01-OmpA variants were cloned and heterologously expressed in E. coli host cells and subsequently purified. The results showed increased emulsifying activity of N-terminally truncated SA01-OmpA (NT-OmpA) compared to full-length SA01-OmpA. Molecular dynamics (MD) simulations analysis demonstrated a direct correlation between the C-terminally truncated SA01-OmpA (CT-OmpA) and its expression as inclusion bodies. Analysis of the structure-activity relationship of truncated variants of SA01-OmpA revealed that, compared to the full-length protein, deletion of the β-barrel portion from the N-terminal of SA01-OmpA increased the emulsifying activity of NT-OmpA while lowering its expression as inclusion bodies. Contrary to the full-length protein, the N-terminally truncated SA01-OmpA was not as cytotoxic, according to the MTT assay, FCM analysis, and AO/EB staining. The findings of this extensive study advance our knowledge of SA01-OmpA at the molecular level as well as the design and development of efficient bioemulsifiers.IMPORTANCEPrevious research (Shahryari et al. 2021, mSystems 6: e01175-20) introduced and characterized the SA01-OmpA protein as a multifaceted protein with a variety of functions, including maintaining cellular homeostasis under oxidative stress conditions, biofilm formation, outer membrane vesicles (OMV) biogenesis, and beneficial emulsifying capacity. By truncating the SA01-OmpA protein, the current study presents a unique method for developing protein-type bioemulsifiers. The findings indicate that the N-terminally truncated SA01-OmpA (NT-OmpA) has the potential to fully replace full-length SA01-OmpA as a novel bioemulsifier with significant emulsifying activity. This study opens up a new frontier in bioemulsifiers, shedding light on a possible relationship between the structure and activity of SA01-OmpA truncated forms.

Rhamnolipids: A biosurfactant for the development of lipid-based nanosystems for food applications

Biosurfactants (surfactants synthesized by microorganisms) are produced by microorganisms and are suitable for use in different areas. Among biosurfactants, rhamnolipids are the most studied and popular, attracting scientists, and industries' interest. Due to their unique characteristics, the rhamnolipids have been used as synthetic surfactants' alternatives and explored in food applications. Besides the production challenges that need to be tackled to guarantee efficient production and low cost, their properties need to be adjusted to the final application, where the pH instability needs to be considered. Moreover, regulatory approval is needed to start being used in commercial applications. One characteristic of interest is their capacity to form oil-in-water nanosystems. Some of the most explored have been nanoemulsions, solid-lipid nanoparticles and nanostructured lipid carriers. This review presents an overview of the main properties of rhamnolipids, asserts the potential and efficiency of rhamnolipids to replace the synthetic surfactants in the development of nanosystems, and describes the rhamnolipids-based nanosystems used in food applications. It also discusses the main characteristics and methodologies used for their characterization and in the end, some of the main challenges are highlighted.

Isolation and identification of the alga-symbiotic bacterium Gordonia and characterisation of its exopolysaccharide

An exopolysaccharide (EPS)-producing bacterium TD18, isolated from the culture broth of green alga Scenedesmus obliquus, was identified as Gordonia terrae based on the 100% identity of 16S rRNA sequences and designated Gordonia terrae TD18. The results of compositional and structural analyses and physiochemical tests show that (1) the exopolysaccharide produced by G. terrae TD18 (TD18-EPS) is an acidic hetero-polysaccharide with a molecular weight of 23 kDa, consisting of glucose, mannose, galactose and glucuronic acid, and (2) TD18-EPS is of high thermal stability with a degradation temperature of 308 °C, the solution of which is non-Newtonian pseudoplastic fluid exhibiting good emulsifying properties over a wide range of temperatures, pH and NaCl concentrations. Hence, Gordonia terrae TD18 is the first alga-symbiotic Gordonia strain identified thus far, while TD18-EPS is unique in terms of composition and structure, different from the known Gordonia EPS, with excellent physiochemical properties and thus has potential applications in industry.

Antibacterial activity of exopolysaccharide produced by bee gut-resident Enterococcus sp. BE11 against marine fish pathogens

BACKGROUND

In recent years, the demand for innovative antimicrobial agents has grown, considering the growing problem of antibiotic resistance in aquaculture. Adult Apis mellifera honeybees' gut represents an outstanding habitat to isolate novel lactic acid bacteria (LAB) able to produce prominent antimicrobial agents.

METHODS

In the current study, twelve LAB were isolated and purified from the gut of adult Apis mellifera. The isolates were screened for exopolysaccharide (EPS) production. The most promising isolate BE11 was identified biochemically and molecularly using 16 S rRNA gene sequence analysis as Enterococcus sp. BE11 was used for the mass production of EPS. The partially purified BE11-EPS features were disclosed by its physicochemical characterization. Moreover, the antimicrobial activity of BE11 cell free supernatant (CFS) and its EPS was investigated against some fish pathogens namely, Pseudomonas fluorescens, Streptococcus agalactiae, Aeromonas hydrophila, Vibrio sp. and Staphylococcus epidermidis using well-cut diffusion method.

RESULTS

The physicochemical characterization of BE11-EPS revealed that the total carbohydrate content was estimated to be ~ 87%. FTIR and NMR analysis ascertained the presence of galactose and glucose residues in the EPS backbone. Moreover, the GC-MS analysis verified the heterogeneous nature of the produced BE11-EPS made up of different monosaccharide moieties: galactose, rhamnose, glucose, arabinose sugar derivatives, and glucuronic acid. BE11 CFS and its EPS showed promising antimicrobial activity against tested pathogens as the inhibition zone diameters (cm) ranged from 1.3 to 1.7 and 1.2-1.8, respectively.

CONCLUSION

The bee gut-resident Enterococcus sp. BE11, CFS, and EPS were found to be promising antimicrobial agents against fish pathogens and biofilm producers affecting aquaculture. To the best of our knowledge, this is the first study to purify and make a chemical profile of an EPS produced by a member of the bee gut microbiota as a potential inhibitor for fish pathogens.

The structure, characterization and immunomodulatory potential of exopolysaccharide produced by Planococcus rifietoensis AP-5 from deep-sea sediments of the Northwest Pacific

Polysaccharides derived from microorganisms exhibit diverse structures and bioactivities, making them promising candidates for the treatment of various diseases. However, marine-derived polysaccharides and their activities are relatively little known. In this work, fifteen marine strains were isolated from surface sediments in the Northwest Pacific Ocean for screening of EPS production. Planococcus rifietoensis AP-5 produced a maximum yield of EPS at 4.80 g/L. The purified EPS (referred to as PPS) had a molecular weight of 51,062 Da and contained amino, hydroxyl, and carbonyl groups as its major functional groups. PPS primarily consisted of →3)-α-D-Galp-(1 → 4)-α-D-Manp-(1 → 2)-α-D-Manp-(1 → 4)-α-D-Manp-(1 → 4,6)-α-D-Glcp-(1 → 6)-β-D-Galp-(1→, with a branch consisting of T-β-D-Glcp-(1→. Additionally, surface morphology of PPS was hollow, porous, and sphere-like stack. PPS primarily contained C, N, and O elements, with a surface area of 33.76 m2/g, a pore volume of 0.13 cc/g, and a pore diameter of 1.69 nm, respectively. Based on the TG curve, the degradation temperature of PPS was measured to be 247 °C. Furthermore, PPS demonstrated immunomodulatory activity through dose-dependently upregulating the expression level of cytokines. It significantly enhanced the cytokine secretion at a concentration of 5 μg/mL. To sum up, this study offers valuable insights for screening marine polysaccharide-based immunomodulators.

Marine Microbial Polysaccharides: An Untapped Resource for Biotechnological Applications

As the largest habitat on Earth, the marine environment harbors various microorganisms of biotechnological potential. Indeed, microbial compounds, especially polysaccharides from marine species, have been attracting much attention for their applications within the medical, pharmaceutical, food, and other industries, with such interest largely stemming from the extensive structural and functional diversity displayed by these natural polymers. At the same time, the extreme conditions within the aquatic ecosystem (e.g., temperature, pH, salinity) may not only induce microorganisms to develop a unique metabolism but may also increase the likelihood of isolating novel polysaccharides with previously unreported characteristics. However, despite their potential, only a few microbial polysaccharides have actually reached the market, with even fewer being of marine origin. Through a synthesis of relevant literature, this review seeks to provide an overview of marine microbial polysaccharides, including their unique characteristics. In particular, their suitability for specific biotechnological applications and recent progress made will be highlighted before discussing the challenges that currently limit their study as well as their potential for wider applications. It is expected that this review will help to guide future research in the field of microbial polysaccharides, especially those of marine origin.

Exopolysaccharide Production from Marine-Derived Brevundimonas huaxiensis Obtained from Estremadura Spur Pockmarks Sediments Revealing Potential for Circular Economy

Marine environments represent an enormous biodiversity reservoir due to their numerous different habitats, being abundant in microorganisms capable of producing biomolecules, namely exopolysaccharides (EPS), with unique physical characteristics and applications in a broad range of industrial sectors. From a total of 67 marine-derived bacteria obtained from marine sediments collected at depths of 200 to 350 m from the Estremadura Spur pockmarks field, off the coast of Continental Portugal, the Brevundimonas huaxiensis strain SPUR-41 was selected to be cultivated in a bioreactor with saline culture media and glucose as a carbon source. The bacterium exhibited the capacity to produce 1.83 g/L of EPS under saline conditions. SPUR-41 EPS was a heteropolysaccharide composed of mannose (62.55% mol), glucose (9.19% mol), rhamnose (19.41% mol), glucuronic acid (4.43% mol), galactose (2.53% mol), and galacturonic acid (1.89% mol). Moreover, SPUR-41 EPS also revealed acyl groups in its composition, namely acetyl, succinyl, and pyruvyl. This study revealed the importance of research on marine environments for the discovery of bacteria that produce new value-added biopolymers for pharmaceutical and other biotechnological applications, enabling us to potentially address saline effluent pollution via a sustainable circular economy.

Optimization of Exopolysaccharide Produced by Lactobacillus plantarum R301 and Its Antioxidant and Anti-Inflammatory Activities

In this study, the yield of exopolysaccharide (EPS) from Lactobacillus plantarum R301 was optimized using a single-factor experiment and response surface methodology (RSM). After optimization, the EPS yield was increased with a fold-change of 0.85. The significant factors affecting EPS production, as determined through a Plackett-Burman design and Central Composite Design (CCD), were MgSO₄ concentration, initial pH, and inoculation size. The maximum yield was 97.85 mg/mL under the condition of 0.01% MgSO₄, an initial pH 7.4, and 6.4% of the inoculation size. In addition, the EPS exhibited strong antioxidant activity, as demonstrated by its ability to scavenge DPPH, ABTS, and hydroxyl radicals. The scavenging rate was up to 100% at concentrations of 4 mg/mL, 1 mg/mL, and 2 mg/mL, respectively. Moreover, the EPS also exhibited reducing power, which was about 30% that of ascorbic acid when both tended to be stable with the increased concentration. These results suggest that L. plantarum R301 EPS possesses different antioxidant mechanisms and warrants further investigation. In addition to its antioxidant activity, the EPS also demonstrated good anti-inflammatory activity by inhibiting the inflammation induced by lipopolysaccharide (LPS) in RAW 264.7 cells, which could decrease nitric oxide (NO) production and expression of the proinflammatory cytokine Il-6. These findings suggest that L. plantarum R301 EPS could be used as a potential multifunctional food additive in the food industry.

Biological properties of exopolysaccharides produced by Bacillus spp

There is currently a constant search for ecofriendly bioproducts, which could contribute to various biomedical applications. Among bioproducts, exopolysaccharides are prominent contemporary extracellular biopolymers that are produced by a great variety of bacterial species. These homo- or heteropolymers are composed of monomeric sugar units linked by glycosidic bonds, which are secreted to the external medium. Bacillus spp. are reported to be present in different ecosystems and produce exopolysaccharides with different biological properties such as antioxidant, antibacterial, antiviral anti-inflammatory, among others. Since a great diversity of bacterial strains are able to produce exopolysaccharides, a great variation in the molecular composition is observed, which is indeed present in some of the chemical structures predicted until date. These molecular characteristics and their relations with different biological functions are discussed in order to visualize future applications in biomedical section.

Characterization of Probiotic Pichia sp. DU2-Derived Exopolysaccharide with Oil-in-Water Emulsifying and Anti-biofilm Activities

Probiotic-derived exopolysaccharides are considered as promising sources of carbohydrate with extensive applications in many industries. In the current study, yeast strains were isolated from chicken ingluvies and gizzard samples. According to molecular identification, EPS-producing yeast (Pichia sp. DU2) showed the most similarity to Pichia cactophila (99.67%). Pichia sp. DU2 showed probiotic properties. EPS of Pichia sp. DU2 showed emulsifying activity. The formed emulsions showed 53% (colza oil) and 100% (p-xylene) stability after 24 h. These emulsions were oil-in-water and have stability in the presence of NaCl, KCl, and also acidic and basic conditions. Also, the EPS showed anti-biofilm (29.7-47.6% and 19.06-55.26% against B. cereus and Y. enterocolitica, respectively) and flocculating activities (31.4%). FT-IR showed the presence of various functional groups in EPS structure. Also, its heteropolysaccharide nature was revealed in ¹H-NMR and HPLC analysis. This emulsifying EPS showed significant thermal stability and negative zeta potential, which make it a promising carbohydrate for various industries. Finally, according to the predicted model, the maximal EPS production was achieved at reaction time 36 h, pH 6, yeast extract concentration 1.0%, and sucrose concentration 5%. Pichia sp. DU2 with probiotic properties and producing EPS with emulsifying, anti-biofilm, and flocculating activities can be considered as promising yeast strain in various industries like food and pharmaceutical industries.

Isolation, Characterization, and Compositional Analysis of Polysaccharides from Pinot Noir Wines: An Exploratory Study

It has been reported that polysaccharides in wine can interact with tannins and other wine components and modify the sensory properties of the wine. Unfortunately, the contribution of polysaccharides to wine quality is poorly understood, mainly due to their complicated structure and varied composition. In addition, the composition and molecular structure of polysaccharides in different wines can vary greatly. In this study, the polysaccharides were isolated from pinot noir wine, then separated into high-molecular-weight (PNWP-H) and low-molecular-weight (PNWP-L) fractions using membrane-based ultrafiltration. Each polysaccharide fraction was further studied using size exclusion chromatography, UV-Vis, FT-IR, matrix-assisted laser desorption/ionization-high-resolution mass spectrometry, and gas chromatography-mass spectrometry (GC-MS). The results showed that PNWP-L and PNWP-H had different chemical properties and compositions. The FT-IR analysis showed that PNWPs were acidic polysaccharides with α- and β-type glycosidic linkages. PNWP-L and PNWP-H had different α- and β-type glycosidic linkage structures. FT-IR showed stronger antisymmetric and symmetric stretching vibrations of carboxylate anions of uronic acids in PNWP-L, suggesting more uronic acid in PNWP-L. The size exclusion chromatography results showed that over 72% of the PNWP-H fraction had molecular sizes from 25 kDa to 670 kDa. Only a small percentage of smaller molecular polysaccharides was found in the PNWP-H fraction. In comparison, all of the polysaccharides in the PNWP-L fraction were below 25 KDa, with a majority distributed approximately 6 kDa (95.1%). GC-MS sugar composition analysis showed that PNWP-L was mainly composed of galacturonic acid, rhamnose, galactose, and arabinose, while PNWP-H was mainly composed of mannose, arabinose, and galactose. The molecular size distribution and sugar composition analysis suggested that the PNWP-L primarily consisted of rhamnogalacturonans and polysaccharides rich in arabinose and galactose (PRAG). In comparison, PNWP-H were mostly mannoproteins and polysaccharides rich in arabinose and galactose (PRAG). Further research is needed to understand the impacts of these fractions on wine organoleptic properties.

Molecular Characterization and Biocompatibility of Exopolysaccharide Produced by Moderately Halophilic Bacterium Virgibacillus dokdonensis from the Saltern of Kumta Coast

The use of natural polysaccharides as biomaterials is gaining importance in tissue engineering due to their inherent biocompatibility. In this direction, the present study aims to explore the structure and biocompatibility of the EPS produced by Virgibacillus dokdonensis VITP14. This marine bacterium produces 17.3 g/L of EPS at 96 h of fermentation. The EPS was purified using ion exchange and gel permeation chromatographic methods. The porous web-like structure and elemental composition (C, O, Na, Mg, P, S) of the EPS were inferred from SEM and EDX analysis. AFM analysis revealed spike-like lumps with a surface roughness of 84.85 nm. The zeta potential value of −10 mV indicates the anionic nature of the EPS. Initial molecular characterization showed that the EPS is a heteropolysaccharide composed of glucose (25.8%), ribose (18.6%), fructose (31.5%), and xylose (24%), which are the monosaccharide units in the HPLC analysis. The FTIR spectrum indicates the presence of functional groups/bonds typical of EPSs (O-H, C-H, C-O-H, C-O, S=O, and P=O). The polymer has an average molecular weight of 555 kDa. Further, NMR analysis revealed the monomer composition, the existence of two α- and six β-glycosidic linkages, and the branched repeating unit as → 1)[α-D-Xylp-(1 → 2)-α-D-Glcp-(1 → 6)-β-D-Glcp-(1 → 5)]-β-D-Frup-(2 → 2)[β-D-Xylp-(1 → 4)]-β-D-Xylp-(1 → 6)-β-D-Fruf-(2 → 4)-β-D-Ribp-(1 →. The EPS is thermally stable till 251.4 °C. X-ray diffraction analysis confirmed the semicrystalline (54.2%) nature of the EPS. Further, the EPS exhibits significant water solubility (76.5%), water-holding capacity (266.8%), emulsifying index (66.8%), hemocompatibility (erythrocyte protection > 87%), and cytocompatibility (cell viability > 80% on RAW264.7 and keratinocyte HaCaT cells) at higher concentrations and prolongs coagulation time in APTT and PT tests. Our research unveils the significant biocompatibility of VITP14 EPS for synthesizing a variety of biomaterials.

Lignocellulosic hydrolysate based biorefinery for marine exopolysaccharide production and application of the produced biopolymer in environmental clean-up

The present study deals with the utilization of lignocellulosic hydrolysate-based carbon source for exopolysaccharide (EPS) production using newly reported marine Echinicola sediminis BBL-M-12. This bacterium produced 7.56 g L^-1 and 5.32 g L^-1 of EPS on supplementing 30 g L^-1 glucose and 10 g L^-1 xylose as the sole carbon source, respectively. Whereas on feeding Miscanthus hydrolysate (MCH) with glucose content adjusting to 20 g L^-1, E. sediminis BBL-M-12 produced 6.18 g L^-1 of EPS. The inhibitors study showed bacterium could tolerate higher concentrations of fermentation inhibitors include furfural (0.05%), 5-hydroxymethylfurfural (0.1%), vanillin (0.1%) and acetate (0.5%). Moreover, the EPS composition was greatly altered with the type and concentration of carbon source supplied, although β-D-Glucopyranose, β-D-Galactopyranose, and β-D-Xylopyranose were the dominant monomers detected. Interestingly, E. sediminis BBL-M-12 EPS revealed excellent environmental applications like clay flocculation, oil emulsification, and removal of humic acid, textile dye, and heavy metal from the aqueous phase.

Exopolysaccharides from Marine Microbes: Source, Structure and Application

The unique living environment of marine microorganisms endows them with the potential to produce novel chemical compounds with various biological activities. Among them, the exopolysaccharides produced by marine microbes are an important factor for them to survive in these extreme environments. Up to now, exopolysaccharides from marine microbes, especially from extremophiles, have attracted more and more attention due to their structural complexity, biodegradability, biological activities, and biocompatibility. With the development of culture and separation methods, an increasing number of novel exopolysaccharides are being found and investigated. Here, the source, structure and biological activities of exopolysaccharides, as well as their potential applications in environmental restoration fields of the last decade are summarized, indicating the commercial potential of these versatile EPS in different areas, such as food, cosmetic, and biomedical industries, and also in environmental remediation.

Production and Characterization of a Bioemulsifier Derived from Microorganisms with Potential Application in the Food Industry

There is a growing interest in the development and use of natural emulsifiers, which provide biodegradability as well as non-toxicity along with giving better performance compared to existing emulsifying agents used in the food industry. A large variety of sources of starting material, i.e., the microorganisms, are available to be used, hence giving a diverse range of applications. The focus of this review paper is on the production of bioemulsifiers, which are said to be "green surfactants", from fungi, bacteria and yeasts; furthermore, an overview pertaining to the knowledge gained over the years in terms of characterization techniques is reported. The methods used for the characterization and isolation such as TLC, GC-MS, HPLC, NMR have also been studied. The end-application products such as cookies, muffins, and doughs along with the methods used for the incorporation of bioemulsifiers, microorganisms from which they are derived, properties imparted to the product with the use of a particular bioemulsifier and comparison with the existing food grade emulsifiers has been discussed in detail. The future prospects indicate that newer bioemulsifiers with anti-microbial, anti-oxidant and stabilization properties will prove to have a larger impact, and emphasis will be on improving the performance at an economically viable methodology.

Isolation, purification, and characterization of a novel exopolysaccharide isolated from marine bacteria Brevibacillus borstelensis M42

Marine microbes produce polysaccharides with unique physicochemical and functional properties that help them survive in harsh marine environments. However, only a handful of marine exopolysaccharides (EPSs) have been reported to date. The present study explored the seashore of Visakhapatnam, India, to report a novel exopolysaccharide designated as Br42 produced by Brevibacillus borstelensis M42. The isolate was identified through morphological, biochemical, phylogenetic, and genome sequencing analysis. The studies on fermentation kinetics revealed that EPS Br42 was a primary metabolite with a maximum production of 1.88 ± 0.02 g/L after 60 h when production broth was fortified with 2% glucose. Additionally, EPS Br42 was found to be a heteropolysaccharide consisting of glucose and galacturonic acid with a molecular weight of about 286 kDa. Interestingly, this molecule possesses industrially relevant functional properties such as water-holding (510 ± 0.35%), oil-holding (374 ± 0.12% for coconut oil and 384 ± 0.35% for olive oil), and swelling capacities (146.6 ± 5.75%). EPS Br42 could form an emulsion that was stable at a wide pH range for about 72 h and, in fact, performed better as compared to Span 20, a commercially used synthetic emulsifier. Moreover, this EPS was also found to be heat stable and exhibited non-Newtonian pseudoplastic behavior. These physicochemical and functional properties of polysaccharides suggest that the EPS Br42 has potential for multifarious industrial applications as an emulsifier, stabilizer, viscosifier, and binding agent.

Post-translational modifications and glycoprofiling of palivizumab by UHPLC–RPLC/HILIC and mass spectrometry

Viral infections are progressively becoming a global health burden, as witnessed in the ongoing COVID-19 pandemic. Respiratory Syncytial Virus (RSV) is another highly contagious negative-sense RNA virus that causes lower respiratory tract infections and high mortality in infants. Palivizumab (Synagis^®) is the only humanized monoclonal antibody (mAb) approved by the FDA against RSV. The virus neutralization efficacy often depends on the nature and abundance of the glycoforms in therapeutic mAbs. Therefore, a thorough estimation of their PTM profile, especially glycosylation, is relevant. Here, we describe the intact and released glycan analysis of palivizumab (Synagis^®) using HILIC chromatography and mass spectrometry. We detected five glycoforms (Man5/G0FB, G0F/G1F, G1F/G1F, G0FB/G0FB, and G2F/G2F) in deconvoluted MS spectra of intact glycosylated palivizumab. The mapping of the peptide and glycopeptides using LC–ESI–MS led to the detection of associated PTMs and the direct identification of a glycopeptide, GlcNAc₃Man₂. EEQYNSTYR, derived from the heavy chain of palivizumab.Release glycan analysis using UHPLC–HILIC revealed a typical glycan profile consisting of major glycans, G0F (33.94%), G1F (35.50%), G2F (17.24%) also reported previously and minor G1F’ (5.81%), Man5 (3.96%) and G0FB (2.26%) forms with the superior resolution of isomeric G1F/G1F’. Next, we provide the first experimental evidence of Neu5Gc in the commercial palivizumab formulation using DMB labelling. The estimated monosaccharide composition was consistent with previous studies. The findings of the study highlight the efficiency of the release glycan method in providing a correct measure of the total palivizumab glycan pool compared to the intact glycoprotein/glycopeptide approach. The UHPLC–RPLC/HILIC and MS combinations provide a more comprehensive glycoprofile assessment due to the parallel use of fluorescent labels for the analysis of the release of N-glycan, sialic acid, and monosaccharide composition. This approach is suitable for quick quality testing and market surveillance of therapeutic mAbs. Alongside a well-perceived need for cost-effective immunoprophylaxis and the ongoing fast-paced development of next-generation variants of palivizumab, such as MEDI8897, the study reiterates glycosylation as a critical parameter that needs monitoring for drug characterization and quality control.

Production and Characterization of Exopolysaccharide From Newly Isolated Marine Probiotic Lactiplantibacillus plantarum EI6 With in vitro Wound Healing Activity

Because of its safety, biological activities, and unique properties, exopolysaccharide (EPS) from lactic acid bacteria (LAB) has been developed as a potential biopolymer. A few studies have investigated the EPS produced by marine LAB. This study reports the wound healing activity of an EPS produced by a marine isolate identified as Lactiplantibacillus plantarum EI6, in addition to assessing L. plantarum EI6's probiotic properties. EI6 demonstrated promising antimicrobial activity against different pathogenic bacteria, as well as the ability to withstand stomach pH 3, tolerate 0.3% bile salt concentration, and exhibit no signs of hemolysis. Furthermore, EI6 was able to produce 270 mg/L of EPS upon growth for 48 h at 37°C in an MRS medium enriched with 1.0% of sucrose. The chemical features of the novel EI6-EPS were investigated: the UV-vis estimated a high carbohydrate content of ~91.5%, and the FTIR emphasized its polysaccharide nature by the characteristic hydroxyl, amide I, II, & III, and glycosidic linkage regions. The GC-MS and NMR analyses revealed the existence of five monosaccharides, namely, rhamnose, galactose, mannose, glucose, and arabinose, existing mainly in the pyranose form and linked together by α- and β-glycosidic linkages. EI6-EPS was found to be safe (IC50 > 100 μg/ml) and induced human skin fibroblasts (HSF) proliferation and migration. These findings imply that EI6 can be used as a safe source of bioactive polymer in wound care.

Exopolysaccharides production from marine Bacillus strains and their antioxidant and bio-flocculant capacities

Microbial exopolysaccharides (EPS) have gained high scientific concern due to their exceptional physicochemical features and high industrial applicability. Owing to their biotechnological importance, the present study was designed to screen and isolate the EPS-producing Bacillus strains based on their growth potential on specific media and colony morphologies. The bacterial isolates Bacillus subtilis Bs1-01, Bacillus licheniformis Bl1-02, and Bacillus brevis Bb1-04 showed excellent EPS production due to their shortened lag phase and abundant biomass production. Shake-flask fermentation valued the maximum production yield of 50.19 ± 1.14 g/L by Bl1-02 after 72 h incubation (about 3.40 times higher than that of Bacillus thuringiensis Bt1-05). The basic component analysis revealed the improved amount of total carbohydrate, reducing sugar ends, and protein contents by Bl1-02 strain. Structural characteristics and functional groups of the EPS characterized by Fourier transform infrared spectroscopy demonstrated that all EPS were in close agreement to each other due to the presence of similar chemical bonds and functional groups. EPS from Bl1-02 strain showed stronger and more stable bio-emulsifying and hygroscopicity activities (12.23%). The crude EPS exhibited potent antioxidant properties which were examined against reducing potential (H₂O₂ scavenging) and total antioxidant tests. Among bio-flocculation activities of EPS at different concentrations, Bs1-01 strain produced EPS at a concentration of 60 mg/mL was observed to show the maximum value of 79.20%. In conclusion, the EPS from marine Bacillus strains showed excellent functional properties suggesting potential industrial applications that demand separate investigations.

Effect of magnetic field on the removal of copper from aqueous solution using activated carbon derived from rice husk

Adsorptive removal of copper by activated carbon derived from modified rice husk (ACRH) was studied in the presence and absence of magnetic field (MF). The ACRH was prepared from the normal rice husk treated by NaOH solution and subsequent pyrolysis at 450 °C in the absence of oxygen. The physicochemical properties of ACRH's were determined before and after the adsorption process to delineate the adsorption mechanism. The BET analysis confirmed that the fabricated ACRH has a specific surface area of 8.244 m²/g with a mesopore to micropore ratio of 0.974. It was observed that the micropore structure gradually replaced the mesopores, and the surface area of the micropore increased (from 0.9219 to 4.1764 m²/g), and the pore diameter was also decreased from 180.381 to 46.249 Å after pyrolysis. The CHNO/S test result reveals that the carbon content was increased from 42 to 67.8% in the ACRH after pyrolysis. The batch sorption studies were performed by varying the initial adsorbate concentration, temperature, agitation speed, pH, adsorbent dose and contact time for magnetic and non-magnetic conditions to analyze the effect of the magnetic field. The univariate studies show that the maximum experimental adsorption capacity was 4.522 mg/g and 3.855 mg/g, respectively, for these two conditions (representing the magnetic impact) at 25 °C with an adsorbent dose of 2 g/L and an agitation speed of 150 rpm. It was also observed that the removal efficiency was 94.55% and 77.96% (magnetic and non-magnetic condition) at pH 7 with a concentration of 10 mg/L in 2 h. The test result on the impact of exposure time on the magnetic field suggested that the magnetic memory influenced the removal efficiency; after 40 to 60 min, the maximum removal efficiency was achieved, around 80 to 90%. The pseudo-second-order kinetic model was best fitted with the experimental data with a rate constant as 0.1749 and 0.1006 g/mg/min for these two conditions. The Temkin model delineates the adsorption isotherm suggesting the heat generated during the adsorption process is linearly abate with the coverage of the surface area of the adsorbent. The thermodynamic model confirms that the copper adsorption is spontaneous (ΔG = - 3.91 kJ/mol and - 6.02 kJ/mol), wherein the negative enthalpy value (ΔH = - 36.74 kJ/mol and - 25.74 kJ/mol) suggested that the process is exothermic irrespective of magnetic interference. The significant enhancement of copper removal was observed by incorporating the magnetic field, showing an increase in sorption capacity by 17.48% and a reduction of reaction time by 88.12%.

Structural Characterisation and Assessment of the Novel Bacillus amyloliquefaciens RK3 Exopolysaccharide on the Improvement of Cognitive Function in Alzheimer's Disease Mice

In this study Bacillus amyloliquefaciens RK3 was isolated from a sugar mill effluent-contaminated soil and utilised to generate a potential polysaccharide with anti-Alzheimer's activity. Traditional and molecular methods were used to validate the strain. The polysaccharide produced by B. amyloliquefaciens RK3 was purified, and the yield was estimated to be 10.35 gL^-1. Following purification, the polysaccharide was structurally and chemically analysed. The structural analysis revealed the polysaccharide consists of α-d-mannopyranose (α-d-Manp) and β-d-galactopyranose (β-d-Galp) monosaccharide units connected through glycosidic linkages (i.e., β-d-Galp(1→6)β-d-Galp (1→6)β-d-Galp(1→2)β-d-Galp(1→2)[β-d-Galp(1→6)]β-d-Galp(1→2)α-d-Manp(1→6)α-d-Manp (1→6)α-d-Manp(1→6)α-d-Manp(1→6)α-d-Manp). The scanning electron microscopy and energy-dispersive X-ray spectroscopy imaging of polysaccharides emphasise their compactness and branching in the usual tubular heteropolysaccharide structure. The purified exopolysaccharide significantly impacted the plaques formed by the amyloid proteins during Alzheimer's disease. Further, the results also highlighted the potential applicability of exopolysaccharide in various industrial and pharmaceutical applications.

Bioprospecting of exopolysaccharide from marine Sphingobium yanoikuyae BBL01: Production, characterization, and metal chelation activity

In the present study, an exopolysaccharide (EPS)-producing bacterial strain was isolated from the Eastern Sea (Sokcho Beach) of South Korea and identified as Sphingobium yanoikuyae BBL01. Media optimization was performed using response surface design, and a yield of 2.63 ± 0.02 g/L EPS was achieved. Purified EPS produced using lactose as the main carbon source was analyzed by GC-MS and found to be composed of α-D-xylopyranose (28.6 ± 2.0%), β-D-glucopyranose (21.0 ± 1.6%), α-D-mannopyranose (18.5 ± 1.2%), β-d-mannopyranose (13.1 ± 1.4%), β-D-xylopyranose (10.2 ± 2.1%), α-d-talopyranose (5.9 ± 1.1%), and β-d-galacturonic acid (2.43 ± 0.8%). Interestingly, different carbon sources (glucose, galactose, glycerol, lactose, sucrose, and xylose) showed no effect on EPS monomer composition, with a slight change in the mass percentage of various monosaccharides. Purified EPS was stable up to 233 °C, indicating its possible suitability as a thickening and gelling agent for food-related applications. EPS also showed considerable emulsifying, flocculating, free-radical scavenging, and metal-complexion activity, suggesting various biotechnological applications.

Hetero-exopolysaccharide from the extremely halophilic Halomonas smyrnensis K2: production, characterization and functional properties in vitro

In this study, we firstly reported the production and the structural characterization of a novel hetero-exopolysaccharide namely EPS-K2 from the extremely halophilc Halomonas smyrnensis K2. Results revealed that EPS-K2 was mainly composed of three monosaccharides including mannose (66.69%), glucose (19.54%) and galactose (13.77%). EPS-K2 showed high thermostability with a degradation temperature around 260 °C, which could make it a suitable candidate for application in thermal processes. Moreover, EPS-K2 showed attractive functional properties. In fact, it exhibited potent antioxidant activity in a dose-dependent manner as assessed in analyses of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, iron chelating and DNA protection ability. Furthermore, EPS-K2 showed strong adhesion inhibition activity against Enterococcus faecalis (75.52 ± 3.35%) and Escherichia coli (61.95 ± 2.48%) at 1 g/l concentration, as well as a high biofilm disruption activity especially against E. coli (70.73 ± 2.78%), at 2 g/l concentration. According to its biotechnological properties, EPS-K2 could be exploited as functional ingredient in food, biomedicine, and pharmaceutical industries.

Structural characterization and functional properties of novel exopolysaccharide from the extremely halotolerant Halomonas elongata S6

Production of extracellular polysaccharides by halophilic Archaea and Bacteria has been widely reported and the members of the genus Halomonas have been identified as the most potential producers. In the present work, a novel exopolysaccharide (EPS-S6) produced by the extremely halotolerant newly isolated Halomonas elongata strain S6, was characterized. According to the HPAE-PAD results, EPS-S6 was mainly composed of glucosamine, mannose, rhamnose and glucose (1:0.9:0.7:0.3). EPS-S6 was highly negatively charged and its molecular weight was about 270 kDa. Studies on its functional properties showed that EPS-S6 had several potential features. It has noticeable antioxidant activities on 2,2-diphenyl-1-picrylhydrazyl (DPPH^•) inhibition and DNA protection, good ability to inhibit and to disrupt pathogenic biofilms, excellent flocculation of kaolin suspension and interesting emulsifying properties at acidic, neutral and basic pH. Therefore, EPS-S6 could have potential biotechnological concern in several fields such as in food, cosmetic and environmental industries.

Marine-Derived Surface Active Agents: Health-Promoting Properties and Blue Biotechnology-Based Applications

Surface active agents are characterized for their capacity to adsorb to fluid and solid-water interfaces. They can be classified as surfactants and emulsifiers based on their molecular weight (MW) and properties. Over the years, the chemical surfactant industry has been rapidly increasing to meet consumer demands. Consequently, such a boost has led to the search for more sustainable and biodegradable alternatives, as chemical surfactants are non-biodegradable, thus causing an adverse effect on the environment. To these ends, many microbial and/or marine-derived molecules have been shown to possess various biological properties that could allow manufacturers to make additional health-promoting claims for their products. Our aim, in this review article, is to provide up to date information of critical health-promoting properties of these molecules and their use in blue-based biotechnology (i.e., biotechnology using aquatic organisms) with a focus on food, cosmetic and pharmaceutical/biomedical applications.

Purification, characterization and anticancer activities of exopolysaccharide produced by Rhodococcus erythropolis HX-2

In the present study, an exopolysaccharide (EPS) producer Rhodococcus erythropolis HX-2 was isolated from Xinjiang oil field, China. The HX-2 EPS (name HPS) production reached 8.957 g/L by RSM in MSM medium. The HPS was purified by ethanol precipitation and fractionation by DEAE-Cellulose and Sepharose column, the yield of HPS was 3.736 g/L. HPS composed by glucose, galactose, fucose, mannose and glucuronic acid. FT-IR spectroscopy indicated the presence of a large amount of hydroxyl groups. NMR spectroscopy indicated the existence of both α and β-configuration for sugar moieties present in HPS. The degradation temperature (255.4 °C) of the HPS was determined by thermogravimetric analysis (TGA). A reticular structure of HPS was observed by SEM and the AFM analysis of the HPS revealed straight chains line. Meanwhile, the WSI and WHC of HPS were 92.15 ± 3.05% and 189.45 ± 5.65%, respectively. Finally, In vitro anticancer activity purified EPS was evaluated on L929 normal cells, A549 cancer cells, SMMC-7721 liver cancer cells and Hela cervical cancer cell. HPS inhibited the growth of cancer cells in a certain concentration without damage to normal cells. These characteristics indicate that its potential application value in food, industry and pharmaceutical application.