Brown Algae Research Articles

A comparative study of extraction methods for recovery of bioactive components from brown algae Sargassum serratifolium

A comparative study of extraction methods for recovery of bioactive components from brown algae Sargassum serratifolium

Brown Algae Ecklonia cava Extract Modulates Adipogenesis and Browning in 3T3-L1 Preadipocytes through HO-1/Nrf2 Signaling.

This study explores the anti-obesity effects of the ethyl acetate extract of Ecklonia cava (EC-ETAC) on 3T3-L1 preadipocytes, focusing on its impact on adipogenesis, lipolysis, and adipose browning via the HO-1/Nrf2 pathway. Western blot analysis revealed that EC-ETAC significantly inhibited adipogenic transcription factors (PPARγ, C/EBPα, SREBP-1) and lipogenesis-related proteins (FAS, LPL). Concurrently, EC-ETAC enhanced lipolytic markers (p-AMPK, p-HSL) and adipose browning-related proteins (UCP-1, PGC-1α), indicating its role in promoting lipolysis and adipose browning. The inhibition of HO-1 by zinc protoporphyrin (ZnPP) significantly reversed these effects, underscoring the critical role of HO-1 in mediating the anti-obesity properties of EC-ETAC. Additionally, fluorescence measurements and Oil Red O staining confirmed the reduction of lipid accumulation and oxidative stress upon EC-ETAC treatment. These findings suggest that EC-ETAC exerts its anti-obesity effects by modulating the HO-1/Nrf2 pathway, which is crucial for regulating adipogenesis, lipolysis, and adipose browning. This study highlights the potential of EC-ETAC as a natural therapeutic agent for obesity management and supports further research into its clinical applications. By targeting the HO-1/Nrf2 pathway, EC-ETAC could offer a novel approach to enhancing energy expenditure and reducing fat mass, thereby improving metabolic health.

Assessing Golden Tides from Space: Meteorological Drivers in the Accumulation of the Invasive Algae Rugulopteryx okamurae on Coasts

Massive accumulations of invasive brown algae Rugulopteryx okamurae are exacerbating environmental and socio-economic issues on the Mediterranean and potentially Atlantic coasts. These golden tides, likely intensified by global change processes such as changes in wind direction and intensity and rising temperatures, pose increasing challenges to coastal management. This study employs the Normalized Difference Vegetation Index (NDVI), with values above 0.08 from Level-2 Sentinel-2 imagery, to effectively monitor these strandings along the coastline of Los Lances beach (Tarifa, Spain) in the Strait of Gibraltar Natural Park from 2018 to 2022. Los Lances beach is one of the most affected by the R. okamurae bioinvasion in Spain. The analysis reveals that wind direction determines the spatial distribution of biomass accumulated on the shore. The highest average NDVI values in the western patch were observed with south-easterly winds, while in the eastern patch, higher average NDVI values were recorded with south-westerly, westerly and north-westerly winds. The maximum coverage correlates with elevated temperatures and minimal rainfall, peaking between July and October. Leveraging these insights, we propose a replicable methodology for the early detection and strategic pre-shore collection of biomass, which could facilitate efficient coastal cleanup strategies and enhance biomass utility for biotechnological applications. This approach promises cost-effective adaptability across different geographic areas impacted by golden tides.

Brown Algae as a Valuable Substrate for the Cost-Effective Production of Poly-γ-Glutamic Acid for Applications in Cream Formulations.

Poly-γ-glutamic acid (γ-PGA) is a carboxylic-acid-rich, bio-derived, water-soluble, edible, hydrating, non-immunogenic polymer produced naturally by several microorganisms. Here, we re-emphasise the ability of Bacillus subtilis natto to naturally produce γ-PGA on whole seaweed, as well as for the yields and chemical properties of the material to be affected by the presence of Mn(2+). Hyaluronic acid (HA) is an extracellular glycosaminoglycan which presents a high concentration of carboxylic acid and hydroxyl groups, being key in fulfilling numerous applications. Currently, there are strong environmental (solvent use), social (non-vegan extraction), and economic factors pushing for the biosynthesis of this material through prokaryotic microorganisms, which is not yet scalable or sustainable. Our study aimed to investigate an innovative raw material which can combine both superior hygroscopicity and UV protection to the cosmetic industry. Comparable hydration effect of commercially available γ-PGA to conventional moisturising agents (HA and glycerol) was observed; however, greater hydration capacity was observed from seaweed-derived γ-PGA. Herewith, successful incorporation of seaweed-derived γ-PGA (0.2-2 w/v%) was achieved for several model cream systems with absorbances reported at 300 and 400 nm. All γ-PGA-based creams displayed shear thinning behaviour as the viscosity decreased, following increasing shear rates. Although the use of commercial γ-PGA within creams did not suggest a significant effect in rheological behaviour, this was confirmed to be a result of the similar molecular weight. Seaweed-derived γ-PGA cream systems did not display any negative effect on model HaCaT keratinocytes by means of in vitro MTT analysis.

Synergistic Antibacterial Effect of Eisenia bicyclis Extracts in Combination with Antibiotics against Fish Pathogenic Bacteria.

The aquaculture industry faces significant challenges due to bacterial infections caused by Edwardsiella tarda, Photobacterium damselae, and Vibrio harveyi. The extensive use of traditional antibiotics, has resulted in widespread antibiotic resistance. This study aimed to investigate the antibacterial potential of the brown seaweed Eisenia bicyclis, particularly its synergistic effects with antibiotics against these fish pathogenic bacteria. E. bicyclis were processed to obtain methanolic extracts and fractionated using different polar solvents. The antibacterial activities of these extracts and fractions were assessed through disc diffusion and minimum inhibitory concentration (MIC) assays. The study further evaluated the antibiotic susceptibility of the bacterial strains and the synergistic effects of the extracts combined with erythromycin and oxyteteracycline using the fractional inhibitory concentration index. Results showed that the ethyl acetate (EtOAc) fraction of E. bicyclis methanolic extract exhibited the highest antibacterial activity. The combination of the EtOAc fraction with erythromycin significantly enhanced its antibacterial efficacy against the tested strains. This synergistic effect was indicated by a notable reduction in MIC values, demonstrating the potential of E. bicyclis to enhance the effectiveness of traditional antibiotics. The findings suggest that E. bicyclis extracts, particularly the EtOAc fraction, could serve as a potent natural resource to counteract antibiotic resistance in aquaculture.

A eutectic mixture catalyzed straight forward production of functional carbon from Sargassum tenerrimum for energy storage application

Here, we present a sustainable and scalable approach for synthesizing functionalized nanomaterials directly from an abundant natural seaweed resource coupled with a green eutectic mixture. The study utilized crushed seaweed granules obtained from fresh brown seaweed Sargassum tenerrimum (ST) and a eutectic mixture generated through the complexation of urea and a metal salt, which act as both solvent and catalyst to facilitate the straightforward production of metal oxide functionalized nanomaterials. Subjecting seaweed granules and the eutectic mixture to pyrolysis at temperatures between 700 °C and 900 °C in a nitrogen (N2) atmosphere resulted in the formation of ST-derived carbon (STC) functionalized with β-MnO2. The nanoneedles thus synthesized were examined for their electrochemical properties in both three-electrode and two-electrode configurations, employing 6 M KOH and 1 M Na2SO4 as electrolytes. Within the three-electrode framework, β-MnO2 functionalized STC at 800 °C (MSTC-8) displayed a remarkable specific capacitance, of 685.1 F g−1 in alkaline electrolyte and 308.3 F g−1 in neutral electrolyte at 0.1 A g−1, demonstrating a superior performance compared to MSTC-7 and MSTC-9. Additionally, two-electrode experiments and evaluations of cyclic stability were performed on MSTC-7, MSTC-8, and MSTC-9 symmetric supercapacitors. The fabricated symmetric supercapacitor in Na2SO4 with the operational voltage window up to 1.7 V, achieved a maximum energy density of 45.5 Wh/kg and a power density of 172.66 W kg−1. Moreover, the current investigation highlights the enduring performance of MSTC-8//MSTC-8 symmetric supercapacitor, with a capacitance retention of 95 % and 80 % over 20,000 cycles in KOH and Na2SO4 electrolytes respectively.

DNA barcoding and phylogenetic relationships of ecologically and commercially important seaweed species from the Azores (NE Atlantic)

Marine natural resources are increasingly demanded to support the livelihoods and wellbeing of humans facing multiple and simultaneous crises across the planet. Seaweeds, in particular, are renowned sources of bioactive marine compounds used for various purposes, including human and animal nutrition, soil fertilization, and healthcare markets. DNA-based tools are being adopted in integrative taxonomy and ecological research, as well as to monitor the supply chain of commercially important species. This research provides novel insights into the population genetics, phylogenetic relationships, and haplotype network of six commercially significant seaweed species that are abundant in the Azores archipelago and currently traded for industrial applications. This study provides a detailed assessment of the genetic diversity of the red seaweeds Asparagopsis armata, Asparagopsis taxiformis, and Pterocladiella capillacea, and the brown seaweeds Halopteris scoparia, Zonaria tournefortii, and Cystoseira pustulata, contributing with 17 newly generated barcodes of COI, rbcL, and 28S rDNA gene records from the Azores region to the reference databases. Understanding the species identification and population dynamics is critical for understanding species composition in biodiversity hotspots. This knowledge supports taxonomy, conservation, environmental protection, and the sustainable use of marine resources.

Effect of distinct drying approach on bioactive compounds and nutritional profiling of Ulva intestinalis and Padina tetrastromatica from the Bay of Bengal, Bangladesh

Marine algae have been visualized as fostering a prevalent actuation of bioactive substances that have noteworthy therapeutic effects. The current investigations deployed a trio of separate drying methods, i.e., oven drying, freeze drying, and sun drying, to quantify the total phenolic content (TPC), total flavonoid content (TFC), and dietary vitality of Ulva intestinalis and Padina tetrastromatica. By mining and scrutinizing it to the quercetin and gallic acid standards, TPC and TFC were derived. Among three drying techniques, freeze drying asserted higher TPC (12.59 ± 1.07 in U. intestinalis and 68.74 ± 1.95 mg of GA/g in P. tetrastromatica) and TFC (7.92 ± 0.97 in U. intestinalis and 58.15 ± 2.05 mg of quercetin/g in P. tetrastromatica) values. Ulva intestinalis and P. tetrastromatica also contain a high amount of protein (18.34% and 8.7%, respectively). The findings demonstrated that green seaweed possessed higher levels of potassium (2.20%) and molybdenum (2.41%) and brown seaweed showed higher amounts of potassium (2.41%) and calcium (1.11%). Where rapid drying methods are recommended to enhance constituent levels, freeze-drying could be an attractive alternative to oven and sun drying, as it addresses the drawbacks associated with prolonged drying periods.

Study on Phytochemical Composition, Biosynthesis and Characterization of Zinc Oxide Nanoparticle Using Sargassum ilicifolium

Nanotechnology involves producing nanoscale materials with specific properties. Zinc oxide nanoparticles have potential applications in various fields. Due to toxic chemicals and environmental concerns, green methods using plants, fungi, bacteria, and algae have been adopted. An emerging area of nanotechnology is the green synthesis of nanoparticles using biological systems, particularly seaweed extracts. The green synthesis method has synthesized the zinc oxide nanoparticles using the aqueous extract of the brown seaweed Sargassum ilicifolium. The algal extract has greatly reduced the zinc acetate dihydrate salt solution to form zinc oxide nanoparticles. The synthesized zinc oxide (Zn-O) nanoparticles have been confirmed through Particle Size Analyzer (PSA), Raman spectroscopy, UltraViolet (UV)- Visible (Vis) spectroscopy, and Scanning Electron Microscope (SEM). The study used Scanning Electron Microscope (SEM) and Particle Size Analyzer (PSA) to examine the size and shape of the Zn-O nanoparticles. Raman spectroscopy and UltraViolet-Vis spectroscopy confirmed the formation of Zn-O nanoparticles. The SEM results exhibited a range of 24.4 nm to 83.4 nm. The occurrence of Zn-O nanoparticles was confirmed by Raman spectroscopy with peaks at 276.98 cm-1, 414.67 cm-1, 462.03 cm-1, 514.99 cm-1, and 998.28cm-1 and UltraViolet-Vis spectroscopy with peak at 370 nm. The present study also deals with the qualitative phytochemical constituent analysis using the aqueous extracts of Sargassum ilicifolium. Alkaloids, flavonoids, cardiac glycoside, tannins, amino acids, carbohydrates, and saponins were analyzed. Anthraquinone, anthocyanin, vitamin C, quinone, and phlobatannins were considered absent in the aqueous extract.

A study on anticancer and antioxidant ability of selected brown algae biomass yielded polysaccharide and their chemical and structural properties analysis by FT-IR and NMR analyses

The study was conducted to determine the chemical and structural properties of polysaccharides extracted from the marine macroalgae Nemalion cari-cariense. Furthermore, evaluate the anticancer and free radical scavenging activity of purified N. cari-cariense polysaccharide. Approximately 41.6% (w/w) of crude polysaccharide was extracted from N. cari-cariense macroalgae biomass. After deproteinization, the purified polysaccharide's major chemical composition was found to be 92.6%, with all protein content removed. The purified polysaccharide had ash and moisture % of 23.01% and 4.03%, respectively. The C, H, and N of the test polysaccharide were analyzed using GC-MS, with results of 39.21%, 5.87%, and 4.29%, respectively. Furthermore, this analysis also revealed the monosaccharide composition such as glucose, galactose, mannose, xylose, and rhamnose glucose, galactose, mannose, xylose, and rhamnose 54.62%, 29.64%, 2.8%, 5.9%, and 6.8% respectively. The molecular weight of purified polysaccharide was found as 49 kDa through PAGE analysis. The FT-IR analysis revealed that the presence of functional groups exactly attributed to polysaccharide and 1H and 13C-NMR analyses confirmed the structural properties of N. cari-cariense polysaccharide. The free radicals scavenging ability of purified N. cari-cariense polysaccharide was investigated by various assays such as total antioxidant assay (22.3%–72.5% at 50–250 μg mL−1), DPPH assay (23.6%–76.9% at 10–160 μg mL−1), OH radical scavenging assay (13.6%–70.2% at 50–250 μg mL−1 dosage, and SO radical scavenging assay (27.6–68.41% at 50–250 μg mL−1 concentration). The polysaccharide demonstrated 82.63% anticancer activity towards the A549 lung cancer cell line at 1000 μg mL−1 dosage. The findings suggest that this polysaccharide has biological applications.

A Comparative Analysis of the Anti-Tumor Activity of Sixteen Polysaccharide Fractions from Three Large Brown Seaweed, Sargassum horneri, Scytosiphon lomentaria, and Undaria pinnatifida.

Searching for natural products with anti-tumor activity is an important aspect of cancer research. Seaweed polysaccharides from brown seaweed have shown promising anti-tumor activity; however, their structure, composition, and biological activity vary considerably, depending on many factors. In this study, 16 polysaccharide fractions were extracted and purified from three large brown seaweed species (Sargassum horneri, Scytosiphon lomentaria, and Undaria pinnatifida). The chemical composition analysis revealed that the polysaccharide fractions have varying molecular weights ranging from 8.889 to 729.67 kDa, and sulfate contents ranging from 0.50% to 10.77%. Additionally, they exhibit different monosaccharide compositions and secondary structures. Subsequently, their anti-tumor activity was compared against five tumor cell lines (A549, B16, HeLa, HepG2, and SH-SY5Y). The results showed that different fractions exhibited distinct anti-tumor properties against tumor cells. Flow cytometry and cytoplasmic fluorescence staining (Hoechst/AO staining) further confirmed that these effective fractions significantly induce tumor cell apoptosis without cytotoxicity. qRT-RCR results demonstrated that the polysaccharide fractions up-regulated the expression of Caspase-3, Caspase-8, Caspase-9, and Bax while down-regulating the expression of Bcl-2 and CDK-2. This study comprehensively compared the anti-tumor activity of polysaccharide fractions from large brown seaweed, providing valuable insights into the potent combinations of brown seaweed polysaccharides as anti-tumor agents.

Biocontrol of tomato Verticillium wilt disease by plant growth-promoting bacteria encapsulated in alginate extracted from brown seaweed

The use of beneficial microorganisms and polysaccharides for the biocontrol of plant diseases currently represents a promising tool for the management of soil-borne pathogens. Despite advancements, enhancing the efficacy and sustainability of these biocontrol methods, particularly in complex soil environments, remains a challenge. Thus, we investigated the potential of four PGPR strains encapsulated in natural alginate extracted from a brown seaweed Bifurcaria bifurcata to evaluate its biocontrol capacities against Verticillium wilt of tomato, ensuring optimal performance through a synergistic effect and innovative bacterial release. Our research demonstrated that the application of PGPR and alginate reduced disease severity and mortality rate and increased the natural defenses of tomato. Results showed that supplying alginate or the PGPR consortium at the root level s stimulates phenylalanine ammonia-lyase activity (the key enzyme of the phenylpropanoid metabolism) and the accumulation of phenolic compounds and lignin in leaves and roots. Treatment with PGPR encapsulated in alginate beads showed the best biocontrol efficiency and was accompanied by a synergistic effect reflecting a rapid, intense, and systemic induction of defense mechanisms known for their effectiveness in inducing resistance in tomato. These promising results suggest that such bioformulations could lead to innovative agricultural practices for sustainable plant protection against pathogens.

Cell wall-mediated maternal control of apical-basal patterning of the kelp Undaria pinnatifida.

The role of maternal tissue in embryogenesis remains enigmatic in many complex organisms. Here, we investigate the contribution of maternal tissue to apical-basal patterning in the kelp embryo. Focussing on Undaria pinnatifida, we studied the effects of detachment from the maternal tissue using microsurgery, staining of cell wall modifications, morphometric measurements, flow cytometry, genotyping and a modified kelp fertilisation protocol synchronising kelp embryogenesis. Detached embryos are rounder and often show aberrant morphologies. When a part of the oogonial cell wall remains attached to the zygote, the apical-basal patterning is rescued. Furthermore, the absence of contact with maternal tissue increases parthenogenesis, highlighting the critical role of maternal signals in the initial stages of development. These results show a key role for the connection to the maternal oogonial cell wall in apical-basal patterning in kelps. This observation is reminiscent of another brown alga, Fucus, where the cell wall directs the cell fate. Our findings suggest a conserved mechanism across phylogenetically distant oogamous lineages, where localised secretion of sulphated F2 fucans mediates the establishment of the apical-basal polarity. In this model, the maternal oogonial cell wall mediates basal cell fate determination by providing an extrinsic patterning cue to the future kelp embryo.

Hypolipidemic effect of polysaccharide from Sargassum fusiforme and its ultrasonic degraded polysaccharide on zebrafish fed high-fat diet

Sargassum fusiforme is a brown seaweed that grows abundantly along the rocky coastlines of Asian countries. The polysaccharides derived from Sargassum fusiforme (SFPS) have received much interest due to their various bioactivities, such as hypolipidemic, hypoglycemic, and antioxidant activities. In this study, we extracted and purified SFPS, and obtained the ultrasonic degradation product (SFPSUD). The lipid regulatory effects of SFPS and SFPSUD were investigated in a zebrafish model fed a high-fat diet. The results showed that SFPS significantly decreased the levels of total cholesterol (TC) and triglycerides (TG), and increased the activities of lipoprotein lipase (LPL) and hepatic lipase (HL). SFPSUD was more effective than the SFPS in reducing the TC and TG levels in zebrafish, as well as increasing the LPL and HL activities. Histopathological observations of zebrafish livers showed that SFPSUD significantly improved lipid metabolism disorder in the hepatocytes. The possible lipid-lowering mechanism in zebrafish associated with SFPS and SFPSUD may involve acceleration of the lipid metabolism rate by increasing the activities of LPL and HL. Thus, SFPSUD could be tested as a highly effective hypolipidemic drug. Our results suggest that SFPS and SFPSUD have potential uses as functional foods for the prevention and treatment of hyperlipidemia. Ultrasound can be effectively applied to degrade SFPS to improve its physicochemical properties and bioactivities.

Collective Total Synthesis of Ecklonialactones, Eiseniachlorides and Analogs.

Ecklonialactones, Eiseniachlorides, and Egregiachlorides are synthesized in living organisms via the lipoxygenase-mediated oxidation of polyunsaturated fatty acids. Originally isolated and identified from brown seaweed (Ecklonia stolonifera, Eisenia bicyclis, and Egregia menziesii), and later replicated on milligram scale through chemical synthesis, the full biological activities of these compounds remain to be elucidated. To bridge this gap in knowledge, we propose a unified methodology to synthesize the 14-membered macrocyclic structures of Ecklonialactones, Eiseniachlorides and analogs using a versatile and convergent approach. This study delineates the synthesis of Ecklonialactone A, B, C, D, and Eiseniachlorides A and B, as well as ent-Ecklonialactone B, 16-epi-Ecklonialactone B and 12,13-diepi-Ecklonialactone B.

Dissolved organic matter released from beach wrack is source-specific and molecularly highly diverse

Beach wrack is an important supplier of nutrients and organic matter to sandy beach ecosystems and underlying subterranean estuaries (STEs), producing metabolic hotspots in these otherwise organic carbon- and nutrient-poor environments. To assess the impact of beach wrack type (e.g., marine, terrestrial, plant, animal) and environmental settings (e.g., tidal inundation, precipitation, and solar irradiation) on nutrient and dissolved organic matter (DOM) release, a series of leaching experiments was conducted. Quantities of leached nutrients and dissolved organic carbon (DOC) were determined, and DOM molecular composition was investigated using Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR-MS). Millimolar—to molar amounts of DOC and dissolved nitrogen were released from the beach cast per kg dry weight, with type of wrack and leaching medium (fresh- vs. saltwater) exerting the biggest influences. Exemplary for animal cast, jellyfish leached up to two 100-fold more, mostly organic, nitrogen compared to all other beach wrack types. FT-ICR-MS data of solid-phase extracted DOM indicated that beach wrack releases compounds with putative mono- and oligosaccharide-, amino acid- and vitamin-type molecular formulae, which likely serve as valuable substrate for heterotrophic microorganisms. DOM from the brown seaweed Fucus sp. was more aromatic than seawater DOM and even beach wrack of terrestrial origin, probably from structural components and secondary metabolites such as phlorotannins. We conclude that DOM and nutrient release from beach wrack strongly depends on wrack type and leaching medium, may obscure molecular provenance proxies (e.g., terrestrial indices), and adds a nutritional boost to infiltrating sea- and rainwater which likely impact microbial respiration rates in the STE.

Phenolic compound derived from Enteromorpha intestinalis and their bioactivity against bacterial pathogens

The purpose of the study was to assess a phenolic compound that was extracted from the brown seaweed Enteromorpha intestinalis (Linn.), Nees (1820) for its antibacterial activities on different bacterial pathogens of fish illnesses. Hexane and methanol were utilized to extract bioactive compounds from the seaweed. Phytochemical analysis of the methnaolic extracts have revealed the presence of carbohydrates and glycosides, saponins, alkaloids, amino acids, flavonoids, fixed oil and fat, phenol compounds, tannins, and steroids. The bacterial pathogens of fish, including Providencia vermicola, Aeromonas hydrophila, Vibrio harveyi, and Aeromonas caviae, were targeted for antibacterial assessment. Among them, the methanolic crude extract and fraction-1 of E. intestinalis have shown maximum activity against A. hydrophila (22 ± 0.13 and 33 ± 0.56 µg/mL). Column chromatography was employed to isolate effective seaweed fraction, while FT-IR and HPLC were utilized for characterization. The phytochemical analysis confirmed the presence of various compounds in both extracts. The crude methanolic extract of E. intestinalis have demonstrated the maximum efficacy beside the tested bacterial pathogens. The FT-IR analysis revealed functional groups associated with polymeric structures in the seaweed extracts, including alcohols, phenols, aromatics, alkyl halides, aliphatic amines, alkynes, and alkenes. Overall, the methanolic extract of E. intestinalis exhibited significant antibacterial activity as a result of the phenolic chemicals that are present. The study provides valuable baseline data, emphasizing the need for further research towards developing antibacterial drug formulations.

Study of mercury adsorption using biochars derived from the invasive brown seaweed “Sargassum muticum” as a low-cost and ecofriendly adsorbent in the aqueous phase

Study of mercury adsorption using biochars derived from the invasive brown seaweed “Sargassum muticum” as a low-cost and ecofriendly adsorbent in the aqueous phase

A comprehensive review of current progress in biofuel production using marine algae biomass

The world's fossil fuel resources are rapidly depleting as the global population grows and energy demands rise. Current fossil fuel supplies are insufficient to meet rising demand and are nearing depletion. Careless exploitation of fossil fuels increases greenhouse gas emissions, environmental pollution, and global warming, resulting in ecological imbalances and health risks. Consequently, contamination, rising temperatures, and high oil costs have fueled the search for renewable and alternative energy sources. This study seeks to explore renewable energy alternatives that are critical to meeting future global energy demands. Marine algae such as red algae, green algae, and brown algae are gaining popularity as economically viable and environmentally friendly sources of renewable biofuel. Several studies are currently underway to assess the ability of marine algae to produce a variety of bioproducts, including biofuels. Macroalgae, in particular, emerges as an ideal resource for biofuel production due to their lipid and carbohydrate content, coupled with low or absent lignin content. The article investigates the potential of marine algal species to promote biofuel production and discusses novel methods for improving biofuel yields. It also emphasizes the economic factors and challenges associated with sustainable biofuel production.

Nutritional and techno-functional properties of the brown seaweed Sargassum filipendula

With the increasing need to promote healthy and sustainable diets, seaweeds emerge as an environmentally friendly food source, offering a promising alternative for food production. The aim of this study was to characterize the brown seaweed Sargassum filipendula from the coast of São Paulo, Brazil, regarding its nutritional and techno-functional properties using two dehydration methods, oven drying and lyophilized. A commercial dried sample was used as a control. Analyses of proximate composition, mineral determination, amino acid determination, antioxidant capacity, pH, color, scanning electron microscopy, X-ray diffraction, thermal properties, Fourier-transform infrared spectroscopy, and techno-functional properties were performed. Seaweed flours showed significant differences in physicochemical composition, with dietary fiber content of seaweed flours exceeding 70 %. Glutamic and aspartic acids were the most abundant amino acids, with contents of 88.56 and 56.88 mg/g of protein in Sargassum oven drying. Both for antioxidant potential and bioactive compounds, Sargassum lyophilized flours showed the highest levels of compounds. Sargassum lyophilized exhibited lighter color compared to Sargassum oven drying and Sargassum commercial. Emulsion formation, foam formation capacity and stability were higher in Sargassum lyophilized, as well as water and oil absorption. The results suggest that seaweeds can be used to formulate a wide variety of food products, such as sausages, bread, cakes, soups, and sauces.