Search Results (501)

Low-salinity events caused by heavy rainfall and freshwater runoff pose significant environmental constraints on eucheumatoid seaweed mariculture in coastal areas. In this study, five eucheumatoid seaweeds, including three strains of Kappaphycus alvarezii (Hn-R, Hn-G, and Ma-R), Kappaphycus striatum, and Eucheuma denticulatum, were exposed to 22, 26, and 30 psu for 36 days. Growth performance, photosynthetic pigments, chlorophyll fluorescence parameters, oxidative damage, and antioxidant responses were determined. To compare the actual physiological performance of different seaweeds under each salinity condition, a functional performance score was calculated using membership function analysis based on relative growth rate, chlorophyll a, carotenoids, photosynthesis, and malondialdehyde. Low salinity generally reduced growth, photosynthetic pigment content, and photosystem II performance, while increasing malondialdehyde content and antioxidant-related parameters, indicating that prolonged low-salinity exposure induced both physiological inhibition and oxidative stress responses. At 22 psu, K. alvarezii Ma-R showed the strongest functional performance, followed by K. striatum and E. denticulatum. At 26 psu, E. denticulatum showed the strongest functional performance, followed by K. alvarezii Ma-R and K. striatum. These results indicate that eucheumatoid seaweeds differ in their functional performance under mild and more severe low-salinity tolerance, providing physiological evidence for selecting candidate eucheumatoid seaweeds for salinity-fluctuating coastal mariculture. Full article

Brown algae are important primary producers in coastal ecosystems, where they provide habitat and food for numerous marine species. For humans, they provide raw materials (food, animal feed, and ingredients for pharmaceuticals and cosmetics) as well as ecosystem services such as coastal protection and carbon sequestration. The molecular characterization of brown algae is necessary to understand their role in ecosystems, their biochemical resources, and responses to environmental stresses—knowledge that is crucial for the sustainable use and biotechnological applications of seaweed. Within this context, we analyzed more than 300 primary and secondary metabolites by gas chromatography–mass spectrometry to elucidate the metabolic profiles of seven habitat-forming species of brown algae in the arctic and temperate seas. Metabolite profiles were discussed considering physiological and ecological characteristics of the different algae, thus revealing the taxon-specific biochemical signatures and metabolite patterns contributing to seaweed adaptation to their typical habitats. Three important groups of metabolites representing polyols, phenolic compounds, and organic acids, were analyzed and discussed in more detail. Our study revealed metabolic diversity of species from the same order and genus, thereby indicating a very distinct regulation at the molecular level to meet metabolic needs of the habitat. The knowledge of different compositions of algal extracts can be used to develop specialized applications for humans in cosmetic, medical, or nutritional sectors. Full article

Due to large-scale macroalgal blooms, nutrient enrichment, and changes in ocean circulation brought on by climate change, beach-accumulated seaweed (BAS) has quickly become a global environmental and waste-governance concern. Despite degradation and contamination during beach stranding, BAS retains valuable bioactive compounds, including sulfated polysaccharides, phlorotannins, pigments, proteins, peptides, and lipids, which exhibit anti-inflammatory, antioxidant, antimicrobial, antiviral, immunomodulatory, anticancer, and metabolic regulatory activities. This review critically evaluates BAS as a sustainable bioresource by integrating current knowledge on biomass composition, degradation-associated challenges, bioactive properties, valorization pathways, advanced extraction technologies, safety validation, regulatory considerations, and emerging commercialization opportunities. Attention is given to sustainable valorization pathways, ranging from composting and bioenergy production to the recovery of high-value bioactives through enzyme-assisted, green, and advanced extraction technologies. The review further discusses policy and regulatory gaps, contamination challenges, safety validation requirements, and life-cycle sustainability considerations that currently limit industrial adoption. Finally, emerging opportunities involving metabolomics, microbial bioprocessing, artificial intelligence, automation, and nanotechnology are explored as future directions for transforming BAS into a standardized and economically viable feedstock within the circular blue bioeconomy. Establishing harmonized regulatory frameworks and integrating BAS management with Sustainable Development Goals (SDGs) 12 and 14 will be critical for enabling sustainable resource recovery and long-term coastal resilience. Full article

Soil water retention is a key factor in ecological processes regulating ecosystem stability and resilience under environmental stress. In this regard, marine-derived additives may provide sustainable strategies to enhance soil water dynamics. Here, novel biopolymers derived from thermophilic bacteria, including six exopolysaccharides (EPS1–EPS6) and four biosurfactants (BS1-BS4), and biomasses from seaweed (BM1–BM4) and marine cyanobacteria (BC1–BC2), were investigated for their wetting properties and soil water retention. Wetting properties, including reduction in contact angle (RCA) and atmospheric-air moisture uptake (AMU), were monitored for 36 h at constant temperature (30 °C). The effect on soil water retention was evaluated in terms of water loss of soil samples treated with two different concentrations (0.5 and 1% w/w) of either biopolymers or biomasses in a microcosm consisting of 10 g of soil and 10 mL of water, kept at a stable temperature of 22 °C for 200 h (until complete evaporation occurred). BC2 derived from Leptolyngbya sp. 43.3 was the best wetting agent (RCA = 39.44%), while the EPS4 produced by Bacillus horneckiae SBP3 was the best humectant agent (AMU = 179.63%). Soils amended with bacterial biopolymers (EPS4, EPS5, EPS6, BS1 and BS3), as well as biomasses derived from cyanobacteria BC2 and seaweed BM1–BM4, produced better improvement in soil water retention, with marked effects at the concentration of 1% w/w. The lipopeptide BS1 was the most effective in water loss reduction over a specific time of 96–125 h at both concentrations. These findings highlight the potential of these materials as nature-based solutions to improve soil-mediated ecosystem resilience to drought under climate change. Full article

The replacement of fishmeal (FM) in aquafeeds for carnivorous fish remains challenging due to reduced palatability and adverse effects on liver health and intestinal microbiota. Marine by-products-based additives containing fish protein hydrolysates and seaweed polysaccharides have shown potential to overcome these limitations. This study evaluated the effects of graded supplementation of Haiweisu (HWS), a multi-marine by-product formulated with squid viscera hydrolysate, small-molecule components from fish protein hydrolysate, seaweed polysaccharides, and seaweed residue as a carrier, in a FM-free diet for juvenile largemouth bass. Four isonitrogenous and isolipidic diets were prepared: a FM-free control diet (CON) and three diets supplemented with 10, 20, or 30 g/kg HWS (designated S10, S20, and S30, respectively). Each diet was fed to triplicate groups of fish (29.26 ± 2.61 g) for 56 days. Results showed that HWS supplementation linearly increased final body weight, weight gain rate, and feed intake, while significantly reducing the feed conversion ratio (p < 0.05). All HWS-supplemented groups exhibited markedly lower hepatic lipid accumulation and plasma total cholesterol levels compared with the CON group, accompanied by alleviated hepatocellular steatosis and inflammatory infiltration as revealed by Oil Red O and H&E staining. Moreover, HWS significantly enhanced intestinal microbiota alpha diversity (Ace, Chao, Sobs, and Shannon indices), decreased the relative abundance of the dominant genus Mesomycoplasma, and enriched potentially beneficial genera including Methylobacterium, Delftia, and Sphingomonas (p < 0.05). In conclusion, dietary HWS supplementation effectively improved growth performance, alleviated hepatic steatosis and inflammation, and beneficially reshaped the intestinal microbiota in juvenile largemouth bass fed a FM-free diet. These findings support HWS as a promising functional additive for sustainable FM-free aquafeeds in carnivorous fish species. Full article

Microorganisms in sediments participate actively in biogeochemical cycling and are essential for maintaining the stability of marine ecosystems. To investigate the spatial impact of seaweed mariculture on sediment bacterial communities, three distinct zones were selected along the Zhanjiang coast, China: the Gracilaria salicornia aquaculture zone, a transition zone (adjacent to the aquaculture area), and a control zone (with no direct mariculture influence). In this study, 16S rRNA gene amplicon sequencing was employed to examine the composition, diversity, and potential functions of sediment bacterial communities across these three zones. The dominant microbial communities identified included Pseudomonadota, Thermodesulfobacteriota, Chloroflexota, and Acidobacteriota. Analyses of α-diversity, β-diversity, and molecular ecological network revealed that the bacterial community in the G. salicornia aquaculture zone exhibited significant differences in species composition, community structure, and interspecies interaction compared with those in the transition and control zones. Environmental factors such as pH, dissolved oxygen (DO) and nitrate (NO₃⁻) exerted significant influence on the bacterial community composition and structure. Predicted functional potential analyses indicated high abundances of pathways related to carbohydrate metabolism and amino acid metabolism. Overall, this study characterizes the spatial distribution patterns of microbial communities in a coastal seaweed mariculture ecosystem and provides important data to support further research on biogeochemical processes mediated by sediment bacteria and their response mechanisms to mariculture activities. Full article

Type 2 diabetes mellitus (T2DM) is a major global health burden characterized by insulin resistance, progressive pancreatic β-cell dysfunction, and chronic metabolic dysregulation. Marine seaweeds have emerged as a valuable source of bioactive natural products, particularly polyphenols and polysaccharides, with promising potential for diabetes management. This review focuses on three major contributions: first, the structural diversity of seaweed-derived polyphenols and polysaccharides; second, their multi-target mechanisms of glucose regulation; and third, the structure–activity relationships governing their bioactivities. Current evidence shows that these compounds may help manage type 2 diabetes in several ways, including inhibition of α-amylase and α-glucosidase, attenuation of oxidative stress and chronic inflammation, enhancement of insulin secretion and insulin sensitivity, regulation of lipid metabolism, and modulation of gut microbiota. Key structural determinants such as degree of polymerization, hydroxyl group density, sulfation level, molecular weight, and chemical modifications are discussed in relation to their functional properties. By linking chemical structure with biological function, these findings highlight marine seaweeds as a rich reservoir of multi-target therapeutic candidates for T2DM management and provide a scientific basis for their development as functional food ingredients or lead compounds for novel diabetes management drugs. Full article

Bifurcaria bifurcata R. Ross 1958 is a perennial brown seaweed belonging to the Sargassaceae family and represents an underexploited marine bioresource with promising applications in the sustainable food and pharmaceutical sectors. To support its sustainable valorization as an alternative to synthetic additives, this study provides a comprehensive evaluation of the chemical composition, bioactivity, and mineral profile of B. bifurcata to support its valorization. The essential oil, obtained by hydrodistillation and characterized by GC—MS, revealed a rich chemical profile comprising 51 compounds, of which 42 were identified, accounting for 95.37% of the total composition. The major constituents included 2′-hydroxy-4′,5′-dimethylacetophenone (13.11%), benzene, 1-ethyl-3,5-dimethyl- (9.79%), 1,5,9-cyclododecatriene, 1,5,9-trimethyl- (8.57%), and benzene, 1-(1,1-dimethylethyl)-4-methoxy- (8.52%). The essential oil exhibited moderate antioxidant activity under in vitro conditions, with a total antioxidant activity of 74.85 ± 2.78 mg E α-tocopherol/g and IC₅₀ values of 0.103 ± 0.004 (DPPH), 0.106 ± 0.002 (FRAP), and 2.672 ± 0.123 mg/mL (β-carotene bleaching assay). In addition, notable antibacterial activity was observed against Escherichia coli, Staphylococcus aureus, Bacillus subtilis, and Listeria monocytogenes, with inhibition zones ranging from 10 to 12 mm. Mineral analysis of the seaweed powder highlighted its nutritional importance, with high levels of organic matter, proteins, and sugars, along with substantial concentrations of essential macroelements (K, Ca, Mg, and Na) and trace elements (Fe, Mn, and Zn). Overall, these findings demonstrate the potential of B. bifurcata as a sustainable marine resource for the development of natural antioxidants, antimicrobial agents, and mineral-rich ingredients, contributing to environmentally friendly food systems and green pharmaceutical applications. Full article

Due to the environmental concerns associated with petroleum-based plastics, industry and academia have directed increasing attention toward marine-derived biodegradable biopolymers, particularly those obtained from seaweed. In line with global efforts to enhance resource efficiency and sustainability by introducing non-fossil raw materials into the circular economy, seaweed valorization has emerged as a promising pathway. Seaweeds are attractive feedstocks due to their biodegradability, non-toxicity, antioxidant activity, and excellent film-forming capacity. This review provides a critical and application-oriented overview of seaweed biomass for food packaging applications by comparatively discussing the relationship between seaweed composition, extraction technologies, material functionality, packaging performance, and regulatory considerations. Emphasis is placed on the role of structural biopolymers and bioactive compounds in the development of passive, active, and intelligent packaging systems. Recent advances in extraction technologies, polymer modification strategies, and incorporation of functional additives are critically discussed in relation to their influence on the physicochemical, mechanical, barrier, antioxidant, and antimicrobial properties of seaweed-based composites. Furthermore, the review highlights key challenges limiting industrial implementation, including high hydrophilicity, high variability between the batches, energy-intensive drying processes, regulatory compliance, migration safety, and long-term material stability. Overall, seaweed-derived materials demonstrate strong potential as sustainable alternatives to conventional packaging systems, particularly in food applications. However, further optimization of processing technologies, material standardization, techno-economic feasibility, and end-of-life management are still required before large-scale commercialization can be achieved. Full article

Seaweed is increasingly recognized as a sustainable food source with the potential to contribute to Western diets; however, consumer acceptance remains low. This is partly due to undesirable sensory attributes, including fishy and marine flavours present when seaweed is incorporated into foods. Fermentation has been proposed to minimize these off-flavours. This study evaluated the impact of fermentation on the sensory properties of Porphyra umbilicalis (laver). Dark chocolate (54.5% cocoa) was enriched with laver fermented using three cultures: Streptococcus thermophilus (ST), Pediococcus pentosaceus (PP), and Aspergillus oryzae (AO). Five formulations were assessed for consumer acceptability (n = 83) using nine-point hedonic scales and check-all-that-apply (CATA) questionnaires for sensory and emotional responses. All seaweed-containing samples received significantly lower liking scores than the control (overall liking: control = 7.8 ± 0.9; seaweed samples ranging from 5.7 ± 1.8 to 6.6 ± 1.5). Among seaweed-containing samples, AO-fermented laver achieved the highest flavour liking (6.5 ± 1.7) and overall liking (6.6 ± 1.5) scores, both significantly higher than the unfermented sample (flavour: 5.7 ± 1.8; overall: 5.7 ± 1.8; p < 0.05). Correspondence analysis of CATA data explained 88.01% of total variation, with the control associated with positive sensory attributes (sweet, creamy, smooth) while seaweed samples were characterized by off-flavours, fishy, and earthy descriptors. Emotional profiling using the EsSense25 profile indicated that the unfermented sample was exclusively associated with negative emotions (bored, worried, disgusted), while AO was associated with seven positive emotional terms. These findings suggest that fermentation, particularly with AO, may improve the sensory acceptability of seaweed in Western food products when incorporated into familiar matrices. Further research should examine different seaweed species and fermentation strategies to enhance consumer acceptance. Full article

Marine macroalgae are widely distributed renewable resources that offer substantial economic and environmental benefits. This review comprehensively examines seaweeds from the phyla Chlorophyta, Heterokontophyta, and Rhodophyta, highlighting key advances and persistent challenges. Global seaweed production is highly concentrated: Asia accounts for 97% of the total, with China as the dominant producer. These seaweeds synthesize a diverse array of bioactive compounds, including sulfated polysaccharides, phlorotannins, terpenoids, proteins, peptides, polyunsaturated fatty acids, and pigments. Notably, brown algae represent the richest source of both phlorotannins and polyunsaturated fatty acids. To recover these valuable compounds efficiently, a range of advanced green extraction techniques have been developed, such as enzyme-assisted, microwave-assisted, ultrasound-assisted, and supercritical fluid extraction, along with natural deep eutectic solvents. These methods consistently outperform conventional approaches in terms of yield, extraction time, and environmental sustainability. The isolated compounds exhibit a broad spectrum of validated pharmacological activities, including immunomodulatory, anti-inflammatory, anti-diabetic, neuroprotective, antitumor, and antiviral effects. Consequently, they have found diverse applications in functional foods, biomedicine, cosmetics, agriculture, aquaculture, and environmental protection. Despite this promise, critical challenges remain in elucidating structure–activity relationships, developing scalable and sustainable extraction protocols, and advancing clinical translation. Future research should prioritize the discovery of novel marine bioactives, the enzymatic production of oligosaccharides, efficient purification of algal proteins and peptides, and the scaling-up of industrial processes to fully realize the pharmaceutical and biotechnological potential of marine macroalgae. Full article

The demand for naturally derived ingredients in cosmetics is constantly growing, with marine algae emerging as promising candidates due to their rich antioxidant and protective metabolites. Skin aging, driven by oxidative stress, impaired hydration, and weakening of the dermal–epidermal junction (DEJ), manifests as dryness, loss of elasticity, and reduced density. Conventional synthetic antioxidants raise safety concerns, highlighting the need for effective natural alternatives. Ecklonia cava, an edible brown seaweed abundant in phlorotannins, has been reported to possess strong antioxidant and anti-inflammatory properties, yet its effects on key molecular markers of hydration and DEJ integrity remain underexplored. In this study, we standardized an E. cava extract (ECE) and evaluated its antioxidant activity, gene regulatory effects, and clinical efficacy. ECE was standardized by measuring total polyphenols and flavonoids, evaluated by DPPH scavenging assay, and shown to upregulate DEJ-related genes, reinforcing dermal–epidermal cohesion. A randomized clinical trial further confirmed that topical application of ECE improved hydration, elasticity, and density compared with placebo, with benefits evident within weeks. Collectively, these findings establish ECE as a multifunctional cosmetic ingredient capable of protecting the skin while enhancing structural and functional aspects of skin health, supporting its potential application in anti-aging skincare. Full article

Green roofs offer significant potential for urban stormwater management, yet their capacity to improve runoff water quality is constrained by the limited pollutant retention of conventional substrates and inherent nutrient leaching risks. This critical review synthesizes recent advances in substrate engineering and phytoremediation to establish an integrated framework for transforming green roofs into active bio-filtration systems. Our analysis reveals that amending conventional substrates with waste-derived biosorbents substantially enhances heavy metal and nutrient retention through complementary mechanisms of surface complexation, ion exchange, and microprecipitation. When strategically coupled with hyperaccumulator plant species and rhizospheric microbial communities, these amended substrates significantly reduce contaminant loads in urban runoff while maintaining hydraulic functionality. We critically evaluate standard growing media versus substrates amended with targeted biosorbents: biochar, which enhances heavy metal retention and hydraulic conductivity via surface complexation; seaweed biomass, which provides superior water retention and cation exchange while reducing synthetic fertilizer dependence; and chitin-rich crab shell waste, which promotes microprecipitation of metals and phosphates while valorizing marine waste. The novelty resides not in the materials themselves, but in their synergistic combination and the systematic comparative analysis of their retention mechanisms under green roof hydrological conditions. This review further identifies critical engineering trade-offs, including biosorbent-induced hydraulic conductivity reductions and long-term adsorption site saturation, and provides actionable design thresholds for amendment dosing, substrate depth, and species selection. Ultimately, this work establishes a mechanistic and practical roadmap for next-generation green roofs that simultaneously optimize stormwater retention, runoff quality, and circular economy valorization, highlighting priority research directions for long-term field validation and climate-adaptive standardization. Full article

Two new mesophotic species of Chrysymenia are reported for the Gulf of Mexico. Chrysymenia oliverhardyii sp. nov. is a broadly foliose species growing attached to rhodoliths (free-living carbonate nodules predominantly accreted by crustose coralline algae) at 58–66 m depth offshore Louisiana (northwestern Gulf) and at ~64–68 m depth in the vicinity of the Dry Tortugas, Florida (southeastern Gulf). A multi-marker phylogenetic analysis based on chloroplast-encoded rbcL and UPA, as well as nuclear LSU rDNA sequences, indicates that this taxon is most closely related to C. stanlaurelii sp. nov., a slender, branched species from the vicinity of the Florida Middle Grounds, Florida (northeastern Gulf), growing at 60 m depth. These two species from the eastern Gulf of Mexico share a basal most recent common ancestor with respect to the other known species of Chrysymenia. Illustrations and discussion are provided for the new species, as well as for the other Gulf of Mexico members C. planifrons, C. littleriana, C. halymenioides and C. nodulosa. A nomenclatural list, morphological figures, a dichotomous key, and a phylogenetic tree of pertinent Chrysymenia are provided. Full article

Marine seaweeds are recognized as a rich source of structurally diverse bioactive compounds, particularly sulfated polysaccharides with promising biomedical applications. In the present study, a sulfated polysaccharide Codium tomentosum fraction (PSCT) was extracted from the Moroccan green seaweed Codium tomentosum and subjected to comprehensive chemical, structural, and biological characterization. The extraction yield reached 22.01%, and the polysaccharide fraction was mainly composed of neutral sugars (66.84%), along with significant levels of sulfate groups (8.73%) and uronic acids (4.13%). Monosaccharide analysis revealed a predominance of galactose and arabinose, indicating a complex heteropolysaccharide structure. Spectroscopic and morphological analyses (FTIR, XRD, UV–Vis, and SEM–EDS) suggested predominantly amorphous characteristics and confirmed the sulfated profile of the extract. Biological evaluation demonstrated that PSCT exhibits multifunctional bioactivities. The extract showed notable antiviral activity against Herpes Simplex Virus 1 (HSV1), with an EC₅₀ value of 12.22 ± 2.90 µg/mL and no detectable cytotoxicity (CC₅₀ > 200.00 µg/mL). In addition, PSCT displayed strong antimicrobial activity against Staphylococcus aureus, Escherichia coli, and Candida albicans, with remarkably low MIC values ranging from 0.05 to 0.78 mg/mL. Furthermore, antioxidant assays revealed concentration-dependent activity, with up to 68% DPPH radical scavenging and an IC₅₀ of 1.25 mg/mL, indicating a moderate antioxidant potential, along with notable reducing power in the FRAP assay. Overall, these findings highlight the potential of C. tomentosum-derived polysaccharides as multifunctional natural agents with antiviral, antimicrobial, and antioxidant properties, supporting their prospective application in pharmaceutical and biomedical fields. Full article