Upgrading the antioxidant properties of fucoidan and alginate from Cystoseira trinodis by fungal fermentation or enzymatic pretreatment of the seaweed biomass

Advances in oligosaccharides production from brown seaweeds: extraction, characterization, antimetabolic syndrome, and other potential applications

Brown seaweeds are a promising source of bioactive substances, particularly oligosaccharides. This group has recently gained considerable attention due to its diverse cell wall composition, structure, and wide-spectrum bioactivities. This review article provides a comprehensive update on advances in oligosaccharides (OSs) production from brown seaweeds and their potential health applications. It focuses on advances in feedstock pretreatment, extraction, characterization, and purification prior to OS use for potential health applications. Brown seaweed oligosaccharides (BSOSs) are extracted using various methods. Among these, enzymatic hydrolysis is the most preferred, with high specificity, mild reaction conditions, and low energy consumption. However, the enzyme selection and hydrolysis conditions need to be optimized for desirable yield and oligosaccharides composition. Characterization of oligosaccharides is essential to determine their structure and properties related to bioactivities and to predict their most suitable application. This is well covered in this review. Analytical techniques such as high-performance liquid chromatography (HPLC), gas chromatography (GC), and nuclear magnetic resonance (NMR) spectroscopy are commonly applied to analyze oligosaccharides. BSOSs exhibit a range of biological properties, mainly antimicrobial, anti-inflammatory, and prebiotic properties among others. Importantly, BSOSs have been linked to possible health advantages, including metabolic syndrome management. Metabolic syndrome is a cluster of conditions, such as obesity, hypertension, and dyslipidemia, which increase the risk of cardiovascular disease and type 2 diabetes. Furthermore, oligosaccharides have potential applications in the food and pharmaceutical industries. Future research should focus on improving industrial-scale oligosaccharide extraction and purification, as well as researching their potential utility in the treatment of various health disorders.[Figure: see text].

Recent advances in polysaccharide biomodification by microbial fermentation: production, properties, bioactivities, and mechanisms

Polysaccharides are natural chemical compounds that are extensively employed in the food and pharmaceutical industries. They exhibit a wide range of physical and biological properties. These properties are commonly improved by using chemical and physical methods. However, with the advancement of biotechnology and increased demand for green, clean, and safe products, polysaccharide modification via microbial fermentation has gained importance in improving their physicochemical and biological activities. The physicochemical and structural characteristics, biological activity, and modification mechanisms of microbially fermented polysaccharides were reviewed and summarized in this study. Polysaccharide modifications were categorized and discussed in terms of strains and fermentation techniques. The effects of microbial fermentation on the physicochemical characteristics of polysaccharides were highlighted. The impact of modification of polysaccharides on their antioxidant, immune, hypoglycemic, and other activities, as well as probiotic digestive enhancement, were also discussed. Finally, we investigated a potential enzyme-based process for polysaccharide modification via microbial fermentation. Modification of polysaccharides via microbial fermentation has significant value and application potential.

Macroalgal-derived alginate/wastepaper hydrogel to alleviate sunflower drought stress

MAIN CONCLUSION

Alginate/wastepaper hydrogel mitigated sunflower drought stress by increasing the water holding capacity of the soil and decreasing phosphate leaching. The hydrogel promoted sunflower growth and decreased stress related biomarkers. There is a growing interest in the development of biodegradable hydrogels for the alleviation of drought stress on plants. A novel hydrogel based on brown algal-derived alginate and wastepaper was developed and tested as a soil supplement for sunflower growth under moderate (75% field capacity (FC)) and extreme (50% FC) water-deficit stress. The hydrogel showed fast swelling in water, which obeyed the pseudo-first order kinetics. Besides, it increased the water holding capacity of the soil and exhibited a good phosphate adsorption (37 mg PO₄^- g^-1 hydrogel after 6 days) in the soil, and more than 67% of the adsorbed phosphate was desorbed after 20 days. Thus, the phosphate leaching from the hydrogel-amended soil in a column experiment was only 2.77 mg after 4 times of over-irrigation, compared to 11.91 mg without the hydrogel. The hydrogel application promoted various root traits such as fresh and dry biomass, area, and length by > 2-, > 1.6-, > 1.35-, and > 1.3-folds under both water regimes in relation to the no-hydrogel treatments at the same conditions. Furthermore, the sunflower shoots exhibited similar proline contents to the well-watered control (100% FC), with > 50% reduction in relation to the drought-stressed plants under the same conditions. Similarly, the malondialdehyde contents were lowered by > 15%. The analysis of the antioxidant enzymes also indicated a marked reduction in the specific activities of catalase and ascorbate peroxidase under both 75 and 50% FC compared to the respective controls. Additionally, the hydrogel promoted the uptake of phosphate by sunflower roots. These results implied that the developed biodegradable hydrogel could be effectively applied as a soil additive to alleviate drought stress on crops.

Purification and Characterization of the Enzyme Fucoidanase from Cobetia amphilecti Utilizing Fucoidan from Undaria pinnatifida

Fucoidanase is an unstable enzyme with high specificity that requires a large about of time to screen it from microorganisms. In this study, enzymatic hydrolysis was used to produce low-molecular-weight fucoidan from microorganisms via the degradation of high-molecular-weight fucoidan without damage to the sulfate esterification structure of oligosaccharide. The microbial strain HN-25 was isolated from sea mud and was made to undergo mutagenicity under ultraviolet light. Fucoidanase was extracted via ultrasonication and its enzymatic activity was improved via optimization of the ultrasonic conditions. The enzymatic properties and degradation efficiency of fucoidanase were characterized. The microbial strain HN-25 is a Gram-negative aerobic and rod-shaped-cell bacterium, and therefore was identified as Cobetia amphilecti via 16s rDNA. The results proved that fucoidanase is a hydrolytic enzyme with a molecular weight of 35 kDa and with high activity and stability at 30 °C and pH 8.0. The activity of fucoidanase was significantly enhanced by sodium and calcium ions and inhibited by a copper ion and ethylenediaminetetraacetate (EDTA). There was a significant decrease in the molecular weight of fucoidan after enzymatic hydrolysis. The low-molecular-weight fuicodan was divided into four fractions, mainly concentrated at F3 (20~10 kDa) and F4 (≤6 kDa). These consequences suggest that fucoidanase obtained from Cobetia amphilecti is stable and efficient and could be a good tool in the production of bioactive compounds.

Characterization of Sargassum spp. from the Mexican Caribbean and Its Valorization through Fermentation Process

Sargassum is a brown macroalga that has become a general environmental problem in the Mexican Caribbean. Despite the negative effects on the beaches, the algae contain compounds of biotechnological and agronomic interest. The possibility of using sargassum as a substrate under liquid media fermentation (LMF) processes will allow the obtention of bioactive compounds. In this research, five species of Sargassum from the Puerto Morelos region were collected from the beach. The samples were divided into natural Sargassum and washed Sargassum, and the total phenolic compounds (TPC), flavonoids (F), and antioxidant capacity (AOxC) were determined. Once the material was characterized, it was fermented in the LMF process using the Aspergillus niger strain, where the obtained extracts were analyzed. Three holopelagic and one benthic species were identified. The proximal analysis of the seaweed in natural and washed conditions shows adequate carbon–nitrogen ratio values for use as a substrate for microbial degradation. Comparing the fermented extracts with fresh Sargassum, the analyses showed a TPC increase for washed Sargassum fermentation and a TPC decrease for natural Sargassum fermentation; the flavonoid content reached 8-fold higher in the washed Sargassum fermentation. An average AOxC of 57% was achieved during the washed Sargassum LMF process, with a maximum of 69% of ABTS inhibition. Considering these results, Sargassum can be used as a substrate in LMF processes to obtain bioactive compounds.

Fungicidal activities and molecular docking of the marine alga Ulva lactuca and Punica granatum peel extracts on Alternaria tomato spot disease

In this study, we utilized pomegranate peel and marine algae Ulva lactuca (U. lactuca) as rich and sustained sources of bioactive compounds to combat tomato-black spot disease. n-Hexane extracts from the peel of pomegranate (Punica granatum) (PPE) and the marine algal biomass U. lactuca (ULE) were used alone and in combinations to verify their impact against Alternaria alternata (A. alternata). The applied extracts exhibited severe destructive effects on both fungal growth and structure such as mycelia malformation, underdeveloped conidia, cell wall deformation, and shrinkage. Moreover, increased deformations and protrusions, and notch-like structures, were noticed in A. alternata mycelia treated with mixed extracts (PPE and ULE) compared to all other treatments. The protein and reduced sugar contents in tomato fruits were significantly increased in the infected fruits with A. alternata. The highest enzyme activities of pectinase, cellulase, catalase (CAT), and ascorbate peroxidase (APX) were recorded in infected tomatoes in comparison with the healthy ones. Molecular docking studies showed that each extract is rich with bioactive compounds that have a promising inhibition effect on A. alternata cellulases. Pomegranate and Ulva extract showed promising antifungal activity against A. alternata which revealed their feasibility and applicability as biocontrol agents in postharvest disease management and food preservation against fungal pathogens.

Ultrasound-assisted extraction of alginic acid from Sargassum angustifolium harvested from Persian Gulf shores using response surface methodology

In this study, the extraction and characterization of alginic acid, the most abundant compound among brown algae were investigated. The used algae were Sargassum angustifolium from the family of brown algae native to the coasts of the Persian Gulf. The effect of temperature, time, algae mass to solvent volume ratio, and ultrasonic power on the extraction yield and ratio of monomers (M/G) was investigated using the central composite design method. Moreover, the effect of the mentioned parameters on the poly dispersity index and cytotoxic effects against breast cancer cells were also investigated. The maximum obtained extraction yield was 46 %, which was higher than those reported for algae in tropical climates. This shows the effectiveness of ultrasound in facilitating the extraction process. In addition, the minimum monomer ratio was 0.45, the minimum poly dispersity index was 2.5 and the maximum cytotoxicity for using the extract on breast cancer cell line (MCF-7) was 20.3 % (with alginic acid concentration of 250 micrograms per milliliter).

Antioxidant Activities of Natural Polysaccharides and Their Derivatives for Biomedical and Medicinal Applications

Many chronic diseases such as Alzheimer's disease, diabetes, and cardiovascular diseases are closely related to in vivo oxidative stress caused by excessive reactive oxygen species (ROS). Natural polysaccharides, as a kind of biomacromolecule with good biocompatibility, have been widely used in biomedical and medicinal applications due to their superior antioxidant properties. In this review, scientometric analysis of the highly cited papers in the Web of Science (WOS) database finds that antioxidant activity is the most widely studied and popular among pharmacological effects of natural polysaccharides. The antioxidant mechanisms of natural polysaccharides mainly contain the regulation of signal transduction pathways, the activation of enzymes, and the scavenging of free radicals. We continuously discuss the antioxidant activities of natural polysaccharides and their derivatives. At the same time, we summarize their applications in the field of pharmaceutics/drug delivery, tissue engineering, and antimicrobial food additives/packaging materials. Overall, this review provides up-to-date information for the further development and application of natural polysaccharides with antioxidant activities.

Potential of Red, Green and Brown Seaweeds as Substrates for Solid State Fermentation to Increase Their Nutritional Value and to Produce Enzymes

Seaweeds are valuable feedstocks with the potential to be used as ingredients in aquafeeds. However, their use are still limited, given their recalcitrant polysaccharide structure. To break this structure, a biotechnological approach such as solid-state fermentation (SSF) by filamentous fungi can be used, which simultaneously increases the nutritional value of the biomass. However, SSF has hardly been studied in seaweeds; thus, in this study, five different seaweeds (Gracilaria sp., Porphyra dioica, Codium tomentosum, Ulva rigida, and Alaria esculenta) were used as substrates in SSF with Aspergillus ibericus MUM 03.49 and A. niger CECT 2915. Firstly, the seaweeds were fully characterized, and, then, changes in the crude protein and carbohydrate contents were assessed in the fermented biomass, as well as any carbohydrases production. The SSF of U. rigida with both fungi resulted in the maximum xylanase and β-glucosidase activities. The maximum cellulase activity was achieved using Gracilaria sp. and U. rigida in the SSF with A. niger. The protein content increased in C. tomentosum after SSF with A. ibericus and in U. rigida after SSF with both fungi. Moreover, U. rigida's carbohydrate content decreased by 54% and 62% after SSF with A. ibericus and A. niger, respectively. Seaweed bioprocessing using SSF is a sustainable and cost-effective strategy that simultaneously produces high-value enzymes and nutritionally enhanced seaweeds to be included in aquafeeds.

Novel Technologies for Seaweed Polysaccharides Extraction and Their Use in Food with Therapeutically Applications—A Review

The use of seaweed for therapeutic purposes is ancient, but only in the last decade, with advanced technologies, has it been possible to extract seaweed’s bioactive compounds and test their potential properties. Algal metabolites possess nutritional properties, but they also exhibit antioxidant, antimicrobial, and antiviral activities, which allow them to be involved in several pharmaceutical applications. Seaweeds have been incorporated since ancient times into diets as a whole food. With the isolation of particular seaweed compounds, it would be possible to develop new types of food with therapeutically properties. Polysaccharides make up the majority of seaweed biomass, which has triggered an increase in interest in using seaweed for commercial purposes, particularly in the production of agar, carrageenan, and alginate. The bio-properties of polysaccharides are strictly dependent to their chemical characteristics and structure, which varies depending on the species, their life cycles, and other biotic and abiotic factors. Through this review, techniques for seaweed polysaccharides extraction are reported, with studies addressing the advantages for human health from the incorporation of algal compounds as dietary supplements and food additives.

Cloning, expression, and characterization of a novel endo-type alginate lyase from Microbulbifer sp. BY17

BACKGROUND

Alginate oligosaccharides (AOS), with various physiological effects, have been widely used in the food, agricultural, and pharmaceutical industries. The biological enzymatic method of preparing AOS, using alginate lyase, has more advantages compared with physical and chemical methods. Cloning and heterologously expressing alginate lyase are therefore very important.

RESULTS

A novel alginate lyase, BY17PV7, from Microbulbifer sp. BY17, isolated from Gracilaria, was cloned and expressed in Escherichia coli BL21(DE3). BY17PV7 was about 27 KDa. BY17PV7 showed the greatest activity (150.42 ± 3.32 U/mg) at 43 °C and pH 8.9. It could be activated by Ca²⁺ , Mn²⁺ , Co²⁺ , Fe³⁺ , Na⁺ , and inhibited by Mg²⁺ , Zn²⁺ , Ba²⁺ , Cu²⁺ , sodium dodecyl sulfate (SDS), ethylene diamine tetraacetic acid (EDTA). BY17PV7 had a wide range of substrate specificity and good degradation effects for poly β-D-mannuronate (polyM) and poly α-L-guluronate (polyG), demonstrating that it is a bifunctional alginate lyase. The kinetic parameters showed that BY17PV7 had a greater affinity for polyG. BY17PV7 released AOS with a degree of polymerization (DP) of 3-4 in an endolytic manner from sodium alginate. Alginate oligosaccharides showed strong antioxidant ability of reducing Fe³⁺ and scavenging radicals such as hydroxyl, 2,2-azion-bia (3-ethylbenzo-thiazoline-6-sulfonic acid diammonium salt) (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH).

CONCLUSION

A novel bifunctional alginate lyase, BY17PV7, was expressed and characterized in Escherichia coli BL21(DE3). The results were helpful for the analysis of the molecular mechanisms of degrading patterns in the polysaccharide lyase (PL) family. © 2022 Society of Chemical Industry.

Fucoidan-based nanomaterial and its multifunctional role for pharmaceutical and biomedical applications

Fucoidans are promising sulfated polysaccharides isolated from marine sources that have piqued the interest of scientists in recent years due to their widespread use as a bioactive substance. Bioactive coatings and films, unsurprisingly, have seized these substances to create novel, culinary, therapeutic, and diagnostic bioactive nanomaterials. The applications of fucoidan and its composite nanomaterials have a wide variety of food as well as pharmacological properties, including anti-oxidative, anti-inflammatory, anti-cancer, anti-thrombic, anti-coagulant, immunoregulatory, and anti-viral properties. Blends of fucoidan with other biopolymers such as chitosan, alginate, curdlan, starch, etc., have shown promising coating and film-forming capabilities. A blending of biopolymers is a recommended approach to improve their anticipated properties. This review focuses on the fundamental knowledge and current development of fucoidan, fucoidan-based composite material for bioactive coatings and films, and their biological properties. In this article, fucoidan-based edible bioactive coatings and films expressed excellent mechanical strength that can prolong the shelf-life of food products and maintain their biodegradability. Additionally, these coatings and films showed numerous applications in the biomedical field and contribute to the economy. We hope this review can deliver the theoretical basis for the development of fucoidan-based bioactive material and films.

Health benefits and potential applications of fucoidan (FCD) extracted from brown seaweeds in aquaculture: An updated review

Nowadays, the application of immunomodulators in aquaculture has become of an urgent need because of high incidence of fish and shrimp diseases. For a long time, researchers have paid great interest to find suitable, relatively economical, and environmentally safe immunostimulant products to be used either as feed or water additives to boost immunity and increase the resistance of fish and shrimp against the challenging pathogens. Probiotics, prebiotics, synbiotics, phytobiotics, herbal extracts, microalgae, macroalgae, and essential oils have been extensively evaluated. Brown seaweeds (Phaeophyceae) are a large group of multi-cellular macroalgae that are widely distributed in marine aquatic environments. They are abundant in several bioactive sulfated polysaccharides known as fucoidan (FCD). Research studies demonstrated the beneficial functions of FCD in human medicine because of its immunomodulating, antioxidant, anti-allergic, antitumor, antiviral, anti-inflammatory, and hepatoprotective effects. In aquaculture, several researchers have tested the benefits and potential applications of FCD in aquafeed. This literature review provides an updated information and key references of research studies that focused principally on using FCD in aquaculture. Its effects on growth, intestinal health, antioxidant capacity, and immune responses of several finfish and shellfish species will be discussed. This review paper will also highlight the potential efficacy and mechanisms of FCD in the modulation of toxicity signs and increasing the resistance of fish and shrimp against bacterial and viral infections. Hence, this contribution will be valuable to maintain aquaculture sustainability and to improve the health and welfare of farmed fish and shrimp.

Fermentation Affects the Antioxidant Activity of Plant-Based Food Material through the Release and Production of Bioactive Components

This review reports on the effects of fermentation on the chemical constituents and antioxidant activity of plant-based food materials. Fermentation involves a series of reactions that modify the chemical components of the substrate. It could be considered a tool to increase the bioactive compounds and functional properties of food plant materials. Oxidative damage is key to the progression of many human diseases, and the production of antioxidant compounds by fermentation will be helpful to reduce the risk of these diseases. Fermentation also can improve antioxidant activity given its association with increased phytochemicals, antioxidant polysaccharides, and antioxidant peptides produced by microbial hydrolysis or biotransformation. Additionally, fermentation can encourage the breakdown of plant cell walls, which helps to liberate or produce various antioxidant compounds. Overall, results indicated that fermentation in many cases contributed to enhancing antioxidants' content and antioxidant capacity, supporting the fermentation use in the production of value-added functional food. This review provides an overview of the factors that impact the effects of fermentation on bioactive compound composition and antioxidant activity. The impacts of fermentation are summarized as a reference to its effects on food plant material.

Novel postharvest processing strategies for value-added applications of marine algae

Marine algae are regarded as a promising nutrients resource in future as they can be sustainably cultured without land and high investment. These macroalgae are now widely processed into food and beverages, fertilizers and animal feed. Furthermore, bioactive compounds such as polysaccharides and polyphenols in seaweeds have proven to have antibacterial, antiviral and antifungal properties that can be utilized in cosmeceuticals, nutraceuticals and pharmaceuticals. As a key procedure in seaweed production, the postharvest process not only requires more laboured and energy but also affect the quality of the final product significantly. This article reviewed all current postharvest processes and technologies of seaweed and addressed potential postharvest strategies for seaweed production. © 2021 Society of Chemical Industry.

The influence of probiotic fermentation on the active compounds and bioactivities of walnut flowers

In this study, the walnut flowers were fermented using five different probiotics, including two Lactobacillus plantarum, one Lactobacillus bulgaricus, one Lactobacillus casei, and one Lactobacillus rhamnosus. The chemical compositions, antioxidant capacities, and α-glucosidase inhibitory abilities of walnut flowers during fermentation processes were evaluated. The results showed that all the active compounds and bioactivities of the walnut flowers were significantly decreased after 7 days of fermentation, whereas a short-term fermentation (1-3 days) enhanced their bioactivities. Compared to the unfermented sample, L. plantarum (ATCC 8014) and L. rhamnosus (ATCC 53013) increased the ABTS (1.22 and 1.30 times higher) and DPPH radical scavenging activities (up to 1.23 and 1.04 times), respectively. L. plantarum (SWFU D16), L. plantarum (ATCC 8014), and L. rhamnosus (ATCC 53013) improved the ferric reducing antioxidant power which was 110.98%, 133.16%, and 104.76% of the unfermented sample. All five probiotics promoted the α-glucosidase inhibitory ability of walnut flowers (maximum 2.18-fold increase). Three phenolic acids and five flavonoids in the fermentation broth were identified by HPLC, where catechin, epicatechin, and catechin gallate were the dominant components. HPLC results demonstrated that these compounds were degraded and transformed in varying degrees under the effects of probiotics. Taken together, a short-term probiotic fermentation could change the active compounds of the walnut flowers and improve their bioactivities. L. plantarum (ATCC 8014) and L. rhamnosus (ATCC 334) are suggested as suitable strains in producing the fermented walnut flowers. The research findings could further support the development and utilization of walnut flowers as a fermented functional food. PRACTICAL APPLICATIONS: Walnut flowers have been used as fermented food in southwestern China, but their active components and functional activities during fermentation processes are still unclear. This study found that different probiotic fermentation exerted a strong and varied influence on the chemical composition and biological activities of the walnut flowers. A short-term fermentation has significantly improved their antioxidant capacities and α-glucosidase inhibitory abilities, whereas the longer period of fermentation, caused a significant loss of both their active compounds and bioactivities. These findings are useful as a reference for the manufacturers of fermented walnut flowers in selecting suitable strains and fermentation time for their products.

Chinese bayberry Jiaosu fermentation – changes of mycobiota composition and antioxidant properties

The aim of the study was to investigate the dynamic changes of mycobiota community, and the resultant effects on the antioxidant properties during the Chinese bayberry Jiaosu fermentation. The structure and composition of mycobiota during the Chinese bayberry Jiaosu fermentation were significantly changed (p < 0.001) and clearly clustered into two distinct phases (Phase 1: Day 5–20; Phase 2: Day 30–60, p < 0.001). From Phase 1 to Phase 2, the dominant fungi gradually changed from Saccharomycetales fam Incertae sedis to Saccharomyces cerevisiae. The antioxidative properties (total polyphenols, 1,1-diphenyl-2-picrylhydrazyl [DPPH], superoxide and 2,2′-azino-bis-(3-ethylbenzthiazoline-6-sulphonate) [ABTS] radical scavenging) of Chinese bayberry Jiaosu were significantly increased by 250.4, 73.9, 25.3 and 40.0% respectively (p < 0.001). Co-occurrence network analysis revealed that Saccharomyces cerevisiae contributed to the increase of antioxidative properties in the Chinese bayberry Jiaosu fermentation. Our research indicates that fermentation into Chinese bayberry Jiaosu is an effective and new method for high-valued utilization of Chinese bayberry.

Characterization of an organic solvent-tolerant polysaccharide lyase from Microbulbifer thermotolerans DAU221

Alginate and its derivatives are annually produced approximately 30,000 tons or more and are applied to various industries as they are natural polymers. The global market for alginate and its derivatives has been growing steadily. There is little research compared to other enzymes produced through biomass degradation or modification. An alginate lyase, MtAl138, from Microbulbifer thermotolerans DAU221 was cloned and identified in Escherichia coli BL21 (DE3). MtAl138 contains a highly conserved motif (R⁵³⁸TELR, Q⁶⁰⁷IH⁶⁰⁹, and YFKAGVY⁷¹⁶NQ), which indicates that it belongs to the polysaccharide lyase family 7 (PL7). MtAl138, with a molecular weight of 77 kDa worked optimally at 45 °C and pH 7.4. MtAl138 showed twice as much activity as when there was no NaCl when there was between 100 and 600 mM NaCl. Moreover, its activity increased in organic solvents such as benzene, hexane, methanol, and toluene. Based on the thin layer chromatography analyses, MtAl38 is an endo-type enzyme that produces di-, tri-, or tetrasaccharides from polyG and polyM. This study provided that MtAl138 is an endoenzyme that showed outstanding enzymatic activity at concentrated salt solutions and organic solvents, which makes it a reasonably attractive enzyme for use in various industries.

Extracts and Marine Algae Polysaccharides in Therapy and Prevention of Inflammatory Diseases of the Intestine

Inflammatory bowel disease (IBD) is a serious public health problem worldwide. Current therapeutic strategies that use anti-inflammatory drugs, immunosuppressants, and biological treatments are often ineffective and have adverse health effects. In this regard, the use of natural compounds aimed at key pathogenic therapeutic targets in IBD attracts universal attention. Seaweed is a valuable source of structurally diverse biologically active compounds. The materials presented in the review indicate that seaweed extracts and polysaccharides are effective candidates for the development of drugs, biological food additives, and functional nutrition products for the treatment and prevention of IBD. The structural features of algal polysaccharides provide the possibility of exposure to therapeutic targets of IBD, including proinflammatory cytokines, chemokines, adhesion molecules, nuclear factor NF-kB, intestinal epithelial cells, reactive oxygen and nitrogen. Further study of the relationship between the effect of polysaccharides from different types of algae, with different structure and molecular weights on immune and epithelial cells, intestinal microorganisms will contribute to a deeper understanding of their mechanisms and will help in the development of drugs, dietary supplements, functional foods for the treatment of patients with IBD.

Use of algal biorefinery waste and waste office paper in the development of xerogels: A low cost and eco-friendly biosorbent for the effective removal of congo red and Fe (II) from aqueous solutions

The present study investigated the use of algae biorefinery waste and wastepaper in the preparation of cost-effective and eco-friendly xerogels for the removal of congo red (CR) and Fe²⁺. The xerogel properties such as density, swelling degree and porosity were modified by incorporating alginate extracted from the brown seaweed Cystoseira trinodis. The developed biosorbents exhibited a light and porous network structure and were characterized by a fast uptake of CR and Fe²⁺ and adsorption efficiency was increased at pH 6-8. The equilibrium adsorption capacity was found to be 6.20-7.28 mg CR g^-1 biosorbent and 8.08-8.39 mg Fe²⁺ g^-1 biosorbent using different xerogels. The adsorption of CR obeyed first-order kinetics, while, Fe²⁺ followed second-order kinetics. Intraparticle diffusion model suggested a boundary layer effect. The adsorption capacity was maximally obtained as 41.15 mg g^-1 and 169.49 mg g^-1 for CR and Fe²⁺ using wastepaper/Spirulina and wastepaper/alginate/Spirulina xerogel, respectively. Temkin isotherm fitted better to the equilibrium data of CR adsorption than Langmuir and Freundlich models. While, equilibrium data of Fe²⁺ exhibited a best fit to both Langmuir and Freundlich models. Additionally, the Dubinin-Radushkevich isotherm suggested that adsorption mechanism of CR or Fe²⁺ is predominately physisorption. Investigation of thermodynamic parameters such as ΔH° and ΔS° and ΔG° confirmed the feasibility, spontaneity, randomness and endothermic nature of the adsorption process. Electrostatic attraction, H-bonding and n-π interactions were mainly involved in the biosorption process of CR. The results of this study showed that the developed xerogels could be effectively applied for dye and heavy metal removal at low concentrations.

Biochemical Characterization of a New Oligoalginate Lyase and Its Biotechnological Application in Laminaria japonica Degradation

Oligoalginate lyases catalyze the degradation of alginate polymers and oligomers into monomers, a prerequisite for biotechnological utilizing alginate. In this study, we report the cloning, expression and biochemical characterization of a new polysaccharide lyase (PL) family 17 oligoalginate lyase, OalV17, from the marine bacterium Vibrio sp. SY01. The recombinant OalV17 showed metal ion independent and detergent resistant properties. Furthermore, OalV17 is an exo-type enzyme that yields alginate monomers as the main product and recognizes alginate disaccharides as the minimal substrate. Site-directed mutagenesis followed by kinetic analysis indicates that the residue Arg²³¹ plays a key role in substrate specificity. Furthermore, a rapid and efficient alginate monomer-producing method was developed directly from Laminaria japonica. These results suggest that OalV17 is a potential candidate for saccharification of alginate.

Size-dependent whitening activity of enzyme-degraded fucoidan from Laminaria japonica

Fucoidan from Laminaria japonica is a kind of sulfate polysaccharide with high molecular weight (MW) and broad bioactivities. This study was performed to investigate the relationship between MW and whitening activity of fucoidan and to exploit a novel functional ingredient for whitening cosmetics. High sulfate content fucoidan was enzymic degraded by Flavobacterium RC2-3 produced fucoidanase. Two hours were enough for the enzyme degradation to achieve degraded fucoidan with favorable tyrosinase inhibitory ability. The whitening activity of different MW fucoidan fractions were evaluated by their tyrosinase inhibitory ability, antioxidant activity and cellular melanogenesis inhibitory ability. Results showed that in the MW range above 5 kDa, the smaller MW of fucoidan were related to the better whitening activity. The fucoidan fraction with the MW between 5-10 kDa, presented the best tyrosinase inhibitory activity (62.0%), antioxidant activity (48.3%) and excellent anti-melanogenesis ability in B16 cells, which could be applied as the whitening factor in cosmetics development.

Macroalgae as a Valuable Source of Naturally Occurring Bioactive Compounds for the Treatment of Alzheimer's Disease

Alzheimer's disease (AD) is a neurological condition that affects mostly aged individuals. Evidence suggests that pathological mechanisms involved in the development of AD are associated with cholinergic deficit, glutamate excitotoxicity, beta-amyloid aggregation, tau phosphorylation, neuro-inflammation, and oxidative damage to neurons. Currently there is no cure for AD; however, synthetic therapies have been developed to effectively manage some of the symptoms at the early stage of the disease. Natural products from plants and marine organisms have been identified as important sources of bioactive compounds with neuroprotective potentials and less adverse effects compared to synthetic agents. Seaweeds contain several kinds of secondary metabolites such as phlorotannins, carotenoids, sterols, fucoidans, and poly unsaturated fatty acids. However, their neuroprotective effects and mechanisms of action have not been fully explored. This review discusses recent investigations and/or updates on interactions of bioactive compounds from seaweeds with biomarkers involved in the pathogenesis of AD using reports in electronic databases such as Web of science, Scopus, PubMed, Science direct, Scifinder, Taylor and Francis, Wiley, Springer, and Google scholar between 2015 and 2019. Phlorotannins, fucoidans, sterols, and carotenoids showed strong neuroprotective potentials in different experimental models. However, there are no data from human studies and/or clinical trials.

Possibilities of Fucoidan Utilization in the Development of Pharmaceutical Dosage Forms

Fucoidan is a polysaccharide built from L-fucose molecules. The main source of this polysaccharide is the extracellular matrix of brown seaweed (Phaeophyta), but it can be also isolated from invertebrates such as sea urchins (Echinoidea) and sea cucumbers (Holothuroidea). Interest in fucoidan is related to its broad biological activity, including possible antioxidant, anti-inflammatory, antifungal, antiviral or antithrombotic effects. The potential application of fucoidan in the pharmaceutical technology is also due to its ionic nature. The negative charge of the molecule results from the presence of sulfate residues in the C-2 and C-4 positions, occasionally in C-3, allowing the formation of complexes with other oppositely charged molecules. Fucoidan is non-toxic, biodegradable and biocompatible compound approved by Food and Drug Administration (FDA) as Generally Recognized As Safe (GRAS) category as food ingredient. Fucoidan plays an important role in the pharmaceutical technology, so in this work aspects concerning its pharmaceutical characteristics and designing of various dosage forms (nanoparticles, liposomes, microparticles, and semisolid formulations) with fucoidan itself and with its combinations with other polymers or components that give a positive charge were reviewed. Advantages and limitations of fucoidan utilization in the pharmaceutical technology were also discussed.

Combined enzymatic hydrolysis and selective fermentation for green production of alginate oligosaccharides from Laminaria japonica

Alginate oligosaccharides (AOS) showed various biological activities. Traditional protocol for producing AOS was a multiple-step and high-pollution procedure. In this study, a rapid and efficient AOS producing method was developed directly from Laminaria japonica. Natural sun-dried L. japonica with a feed ratio of 1:7 (w/v) was pretreated using cellulase with a dry weight of 3%, for releasing the fermentable sugars (8.5 g/L glucose and 15.2 g/L mannitol). Then, the engineered yeast Yarrowia lipolytica strain with alginate lyase activity was grown using an algae-based medium. After fermentation for 72 h, glucose and mannitol were completely consumed, and 71.8 mM AOS was extracted from the fermentation supernatant. The degree of polymerization (DP) was ranging from 2 to 3. The recovery yield of AOS was about 91.7%. The purity of the extracted AOS was 92.6%. Overall, our work provided new insights for the development of green biotechnologies for oligosaccharide production from seaweed.

Photoprotective Substances Derived from Marine Algae

Marine algae have received great attention as natural photoprotective agents due to their unique and exclusive bioactive substances which have been acquired as an adaptation to the extreme marine environment combine with a range of physical parameters. These photoprotective substances include mycosporine-like amino acids (MAAs), sulfated polysaccharides, carotenoids, and polyphenols. Marine algal photoprotective substances exhibit a wide range of biological activities such as ultraviolet (UV) absorbing, antioxidant, matrix-metalloproteinase inhibitors, anti-aging, and immunomodulatory activities. Hence, such unique bioactive substances derived from marine algae have been regarded as having potential for use in skin care, cosmetics, and pharmaceutical products. In this context, this contribution aims at revealing bioactive substances found in marine algae, outlines their photoprotective potential, and provides an overview of developments of blue biotechnology to obtain photoprotective substances and their prospective applications.