Search Results (22)

The study examines the biosorption potential of Ulva intestinalis (UI) and calcium oxide-modified Ulva intestinalis (CaO-UI) for the environmentally favorable removal of cadmium (Cd²⁺), nickel (Ni²⁺), and lead (Pb²⁺) from aqueous solutions. This research addresses the critical need for sustainable water treatment solutions by developing a green-synthesized biosorbent that combines renewable biomass with enhanced adsorption properties. The adsorption properties of the biomass were improved by preparing calcium oxide (CaO) using Ulva intestinalis extract by green synthesis. Langmuir, Freundlich, and Temkin isotherms were employed to model the results of adsorption experiments that were conducted under a variety of conditions, such as contact time, biosorbent dose, and initial metal ion concentration. Langmuir (R² = 0.999) and Freundlich (R² = 0.999) models both provided an exceptionally well-fitted model for the adsorption isotherms, suggesting a hybrid mechanism that integrates monolayer chemisorption at CaO-active sites and multilayer adsorption on the heterogeneous algal matrix. Key findings demonstrate that the maximum adsorption capacity (qm) of CaO-UI was substantially higher than that of UI, with values of 571.21 mg/g for Cd²⁺, 665.51 mg/g for Ni²⁺, and 577.87 mg/g for Pb²⁺, respectively, in comparison to 432.47 mg/g, 335.75 mg/g, and 446.65 mg/g for UI. The adsorption process was dominated by pseudo-second-order (PSO) chemisorption, as evidenced by kinetic studies (R² = 0.949–0.993). CaO-UI exhibited substantially higher rate constants (k₂ = 9.00–10.15 mg/mg·min) than raw UI (k₂ = 4.72–5.71 mg/mg·min). The green synthesis of calcium oxide has resulted in an increase in surface area, porosity, and functional group density, which is responsible for the enhanced performance of CaO-UI. The adsorption efficacy of Pb²⁺ was the highest, followed by Cd²⁺ and Ni²⁺, which was indicative of the differences in metal ion affinity and hydration energy. These results underscore the potential of CaO-UI as a biosorbent that is both cost-effective and sustainable for the removal of heavy metals in wastewater treatment applications. Full article

Ulva intestinalis holds promise for sustainable aquaculture in the Baltic Sea, but success has so far been limited by high environmental variability. This study examines how environmental factors influence sporogenesis, attachment, and growth of U. intestinalis in the low-salinity Baltic Sea. Optimal sporogenesis was observed at nutrient levels of 4–7 g/L, with peak zoospore release at 22–24 °C. Artificial substrates showed limited attachment success, as competing algae like Pylaiella littoralis and Cladophora glomerata often outperformed Ulva. Mesh cage cultivation demonstrated potential, achieving growth rates similar to controlled systems, though storm-induced turbidity lowered growth. These findings highlight the importance of tailored Baltic Sea cultivation strategies, focusing on nutrient, temperature, water stability, and competition management to enhance Ulva production. As the first pilot experiments in the region, they provide essential input for developing informed strategies that support more detailed trials and future scaled-up production. Full article

This study aimed to biosynthesize zinc oxide nanoparticles (ZnO-NPs) using extracts from various seaweeds, including Ulva lactuca, Ulva intestinalis (Chlorophyta), and Sargassum muticum (Phaeophyceae). The biosynthesized ZnO-NPs were characterized using UV spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, transmission electron microscopy, and zeta potential analysis. Their antimicrobial activity was assessed using the disk diffusion method, revealing significant efficacy against two bacterial species (Klebsiella pneumoniae and Escherichia coli) and two fungal species (Candida albicans and Aspergillus niger). Additionally, the antioxidant potential of the ZnO-NPs was evaluated based on the total antioxidant capacity, ferric reducing antioxidant power, and DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging assays. The antioxidant activity of the ZnO-NPs was confirmed using the three antioxidant assays. The ZnO-NPs of U. lactuca recorded the highest antioxidant activity. The cytotoxicity of the ZnO-NPs was tested on different cell lines using the MTT assay. The ZnO-NPs of U. lactuca showed very weak cytotoxic effects on WI 38 (84.98 ± 4.6 µg/mL) and 23, and this result confirmed its safety on normal cells. The ZnO-NPs of U. lactuca showed moderate cytotoxic effects on the HepG-2 (46.66 ± 2.8 µg/mL) and MCF-7 (30.60 ± 2.1 µg/mL) cell lines. In an in vivo study, the ZnO-NPs of U. lactuca showed a decrease in tumor volume, weight, and serum malondialdehyde in experimental mice, while the total antioxidant capacity of the serum was increased. Histopathological changes in ZnO-NPs indicated a reduction in tumor size, a lower number of mitosis divisions, and a rise in apoptosis correlated with the ZnO-NPs of the U. lactuca-treated groups. In conclusion, biosynthesized ZnO-NPs from seaweed showed potent antimicrobial, antioxidant, and antitumor activities, which can be used in the pharmaceutical industry. Full article

This study explores the potential of producing bioethanol from seaweed biomass and reusing the residues as antioxidant compounds. Various types of seaweed, including red (Gelidium amansii, Gloiopeltis furcata, Pyropia tenera), brown (Saccharina japonica, Undaria pinnatifida, Ascophyllum nodosum), and green species (Ulva intestinalis, Ulva prolifera, Codium fragile), were pretreated with dilute acid and enzymes and subsequently processed to produce bioethanol with Saccharomyces cerevisiae BY4741. Ethanol production followed the utilization of sugars, resulting in the highest yields from red algae > brown algae > green algae due to their high carbohydrate content. The residual biomass was extracted with water, ethanol, or methanol to evaluate its antioxidant activity. Among the nine seaweeds, the A. nodosum bioethanol residue extract (BRE) showed the highest antioxidant activity regarding the 2,2-diphenyl-1-picrylhydrazyl (DPPH) activity, ferric reducing antioxidant power (FRAP), and reactive oxygen species (ROS) inhibition of H₂O₂-treated RAW 264.7 cells. These by-products can be valorized, contributing to a more sustainable and economically viable biorefinery process. This dual approach not only enhances the utilization of marine resources but also supports the development of high-value bioproducts. Full article

This article is about the diversity of diatoms in the benthos of the upper sublittoral near Kazantip Cape, located on the shore of the Sea of Azov in the northeastern part of Crimea. The study was conducted in 2022 and 2023 at a depth of 0.1 to 1 m at temperatures from 3.7 °C to 29 °C and salinity from 13.6 to 15.6 psu on the following 11 species of macroalgae: Phaeophyta of Ericaria crinita, Gongolaria barbata, and Cladosiphon mediterraneus; Chlorophyta—Bryopsis hypnoides, Cladophora liniformis, Ulva intestinalis, and Ulva linza; and Rhodophyta—Callithamnion corymbosum, Ceramium arborescens, Polysiphonia denudata, and Pyropia leucosticta. A total of 97 taxa of Bacillariophyta belonging to 3 classes, 21 orders, 30 families, and 45 genera were found. The highest number of diatom species was found on U. linza (61 species), P. denudata (45), E. crinita (40), the lowest number was recorded on thalli P. leucosticta (9). On macroalgae were found of 80% benthic diatoms, 50% marine species, 36% brackish-marine, 9% freshwater, 5% brackish, and 36% cosmopolites. The maximum abundance of the diatom community was 243.4 × 10³ cells/cm² (P. denudata in September at 23.9 °C and 15.0 psu) with dominance by the diatom of Licmophora abbreviata, and the minimum was 3.8 × 10³ cells/cm² (P. leucosticta in January at 3.7 °C and 15.0 psu). The presence in the epiphyton of diatoms—indicators of moderate organic water pollution (32 species), which developed in masse in late summer—indicate a constant inflow of organic matter into the coastal waters of the Kazantip Cape. The bioindicator and statistical studies indicate the effectiveness of the conservation regime, especially at stations within the IUCN reserve, despite relatively high saprobity rates at stations exposed to recreational pressure and poorly treated domestic wastewater. Full article

Currently, there is growing interest in exploring natural bioactive compounds with anti-inflammatory potential to overcome the side effects associated with the well-known synthetic chemicals. Algae are a rich source of bioactive molecules with numerous applications in medicine. Herein, the anti-inflammatory effect of Ulva intestinalis alone or selenium nanoparticles loaded with U. intestinalis (UISeNPs), after being fully characterized analytically, was investigated by a carrageenan-induced inflammation model. The pretreated groups with free U. intestinalis extract (III and IV) and the rats pretreated with UISeNPs (groups V and VI) showed significant increases in the gene expression of Keap1, with fold increases of 1.9, 2.27, 2.4, and 3.32, respectively. Similarly, a remarkable increase in the Nrf2 gene expression, with 2.09-, 2.36-, 2.59-, and 3.7-fold increases, was shown in the same groups, respectively. Additionally, the groups III, IV, V, and VI revealed a significantly increased HO-1 gene expression with a fold increase of 1.48, 1.61, 1.87, and 2.84, respectively. Thus, both U. intestinalis extract and the UISeNPs boost the expression of the cytoprotective/antioxidant pathway Keap1/Nrf2/HO-1, with the UISeNPs having the upper hand over the free extract. In conclusion, U. intestinalis and UISeNPs have proven promising anti-inflammatory activity through mediating different underlying mechanisms. Full article

Three green algae, collected from the Romanian Black Sea coast, are studied: Ulva lactuca, Enteromorpha intestinalis, and Cladophora vagabunda, which were collected from six different coastal areas. This paper aims to identify the bioactive compounds of these green algae and their beneficial properties, in order to use them as potential nutraceuticals using different analytical methods. Pharmacognostic, microbiological, and physico-chemical methods used for the analysis of algal materials revealed a rich and diverse array of biocompounds with nutritional value. In the case of green algae, a high percentage of sulphates, carbohydrates and dietary fibers were identified. Moisture, ash, total nitrogen, protein and lipid contents were determined. The contents of pigments, vitamins, and metals determined complement the nutritional qualities of the three seaweed species studied as future nutraceuticals. The content of flavonoid and phenolic compounds identified in the composition of seaweeds justifies their antioxidant and antimicrobial properties. The antioxidant capacity was tested by means of DPPH, reducing power, and TEAC methods, and the algae studied exhibit important antioxidant properties that can be used to enhance their potential as nutraceuticals. The studied algae show good antibacterial activity on both Gram (+) and Gram (−) bacteria, with slightly better activity on Gram (−) bacteria. Biocompounds from green algae from the Black Sea coast may represent an important source of marine nutraceuticals with medical and nutritional potential. Full article

Melanogenesis involves a synthesis of melanin pigment and is regulated by tyrosinase. The addition of whitening agents with tyrosinase-inhibiting properties in cosmetics is becoming increasingly important. In this study, the ethanolic extracts from twelve seaweeds were assessed for tyrosinase-inhibiting activity using mushroom tyrosinase and melanin synthesis in B16F10 melanoma cells. The highest mushroom tyrosinase inhibition (IC₅₀) was observed with Lobophora challengeriae (0.15 ± 0.01 mg mL⁻¹); treatment was more effective than kojic acid (IC₅₀ = 0.35 ± 0.05 mg mL⁻¹), a well-known tyrosinase inhibitor. Three seaweeds, Caulerpa racemosa, Ulva intestinalis, and L. challengeriae, were further investigated for their ability to reduce melanogenesis in B16F10 cells. The ethanolic extracts of C. racemosa, U. intestinalis, and L. challengeriae showed inhibitory effects by reducing melanin and intracellular tyrosinase levels in B16F10 cells treated with α-melanocyte stimulating hormone in a dose-dependent manner. C. racemosa (33.71%) and L. challengeriae (36.14%) at 25 µg mL⁻¹ reduced melanin production comparable to that of kojic acid (36.18%). L. challengeriae showed a stronger inhibition of intracellular tyrosinase (decreased from 165.23% to 46.30%) than kojic acid (to 72.50%). Thus, ethanolic extracts from C. racemosa, U. intestinalis, and L. challengeriae can be good sources of natural tyrosinase inhibitors and therapeutic or cosmetic agents in the future. Full article

Macroalgae exhibit beneficial bioactivities for human health. Thus, the aim of the present study was to examine the antioxidant and anticancer potential of 14 macroalgae species’ extracts, namely, Gigartina pistillata, Gigartina teedei, Gracilaria gracilis, Gracilaria sp., Gracilaria bursa pastoris, Colpomenia sinuosa, Cystoseira amentacea, Cystoseira barbata, Cystoseira compressa, Sargassum vulgare, Padina pavonica, Codium fragile, Ulva intestinalis, and Ulva rigida, from the Aegean Sea, Greece. The antioxidant activity was assessed using DPPH, ABTS^•+, ^•OH, and O₂^•− radicals’ scavenging assays, reducing power (RP), and protection from ROO^•-induced DNA plasmid damage assays. Moreover, macroalgae extracts’ total polyphenol contents (TPCs) were assessed. Extracts’ inhibition against liver HepG2 cancer cell growth was assessed using the XTT assay. The results showed that G. teedei extract’s IC₅₀ was the lowest in DPPH (0.31 ± 0.006 mg/mL), ABTS^•+ (0.02 ± 0.001 mg/mL), ^•OH (0.10 ± 0.007 mg/mL), O₂^•− (0.05 ± 0.003 mg/mL), and DNA plasmid breakage (0.038 ± 0.002 mg/mL) and exhibited the highest RP (RP_0.5AU 0.24 ± 0.019 mg/mL) and TPC (12.53 ± 0.88 mg GAE/g dw). There was also a significant correlation between antioxidant activity and TPC. P. pavonica (IC₅₀ 0.93 ± 0.006 mg/mL) exhibited the highest inhibition against HepG2 cell growth. Conclusively, some of the tested extracts exhibited significant chemopreventive properties, and so they may be used for food products. Full article

The objective of this study was to evaluate the effect of surfactant on disperser homogenization pretreatment for macroalgae (Ulva intestinalis) to enhance biogas production. The macroalgae are subjected to surfactant coupled disperser pretreatment, which enhanced the liquefaction and improved the biomethane production. The outcome of this study revealed that 10,000 rpm at 20 min with a specific energy input of 1748.352 kJ/ kg total solids (TS) are the optimum conditions for surfactant disperser pretreatment (SDP), which resulted in the liquefaction rate of 20.08% with soluble organics release of 1215 mg/L and showed a better result than disperser pretreatment (DP) with a liquefaction rate of 14%. Biomethane production through the SDP method was found to be 0.2 g chemical oxygen demand (COD)/g COD, which was higher than DP (0.11 g COD/g COD). SDP was identified to be a synergetic pretreatment method with an energy ratio and net profit of about 0.91 and 104.04 United States dollars (USD)/ton, respectively. Full article

The present study was investigated to know the sensory, physicochemical, nutritional and fatty acid properties of seaweed-based cookies prepared with untapped seaweed Ulva intestinalis (UI) from Bangladesh coast. The cookies were formulated with different percentages of UI inclusions both in powdered (PUI) and fragmented (FUI) forms, in order to evaluate different quality attributes in prepared value-added cookies. In sensory analysis, seaweed inclusion levels of 1% PUI, 2.5% PUI, 1% FUI, 2.5% FUI and 5% FUI to cookies were acceptable by panelists. Considering the maximum percentage of seaweed inclusions, 2.5% PUI and 5% FUI were selected for further analysis. The results of physicochemical properties such as moisture content, spread factor, baking loss, pH, cookie density, color, texture properties, volatile basic nitrogen and thiobarbituric acid reactive species were within acceptable limits. In nutritional analysis, 2.5% PUI and 5% FUI cookies showed a remarkable and significant increase in lipid and ash contents, compared to untreated controls. Being the first report on fatty acids profile by UI from Bangladesh, among 24 fatty acids identified, the amount of total saturated, mono-unsaturated, omega-3 fatty acids and omega-6 fatty acids were reported to be 641.9 (36.2%), 563.7 (31.8%), 133.8 (7.6%) and 436.3 (24.6%) μg/g DW, respectively. The results suggest that cookies with 2.5% PUI and 5% FUI can be marketed as healthy foods for consumers. Full article

The current research focused on algae from the waters of the Black Sea—Chaetomorpha linum, Ulva intestinalis, Ericaria crinita, and bioreactors—Chlorella spp. and Arthrospira platensis/cyanobacterium/. Pigment content, total phenolic content, and antioxidant capacity were investigated for their use as pharmaceutical, food, and cosmetic ingredients. E. crinita exhibited the highest antioxidant activity by ORAC and HORAC (463.3 µmol TE/g and 463.3 µmol GAE/g) and the highest total content of polyphenols and rutin of the investigated algae. Lower protein content was found in saltwater algae than in freshwater algae. For the first time, biologically active substances from the Bulgarian A. platensis and Chlorella spp., produced in a bioreactor, have been quantitatively identified. A. platensis contained rutin (141.25 mg/100 g), naringenin (42.17 mg/100 g), quercetin (26.74 mg/100 g), kaempferol, and quercetin-3-β-glycoside. Phenolic acids were isolated: neochlorogenic (172.27 mg/100 g) for lyophilized and 5783 mg/100 g for convection-dried A. platensis. It has been found that the protein content in A. platensis (convection dried) and Chlorella spp. (lyophilized) was nearly 54% higher than that of green algae U. intestinalis from Varna. The lyophilization process reduced the protein content of A. platensis samples by almost 20%. The high protein content of convection-dried A. platensis (43.4%) and lyophilized Chlorella spp. (43.7%) identified them as suitable emulsifiers in colloidal and emulsion systems. Full article

Food resources are limited in arid countries such as the United Arab Emirates (UAE); the salinity of the groundwater, together with a lack of natural fresh water sources and arable land, force the country to import most of its food. However, seaweed could play an important role in providing a locally available food resource, as it does not require fresh water and arable land to grow. The traditional use of several seaweed species as food sources has been documented in Asia and the Americas, where their nutritional composition has been well reported. Although the UAE’s aquatic environment is quite harsh due to high water salinity (over 40 g/L) and high surface water temperatures (over 35 °C), its native seaweed species could play a role as a food source in this arid region, thereby bolstering the country’s level of food security. To evaluate its potential in this context, fresh samples of the native Ulva intestinalis seaweed were collected in the shallow waters of Abu Dhabi Emirate, UAE. These samples were calculated to contain 34.38 ± 0.24 kcal, with a biomass composition of 5.185 ± 0.04% carbohydrate, 3.32 ± 0.14% protein, and 0.04 ± 0.01% fat (by dry matter). Of all the minerals present in the biomass, potassium had the highest concentration (7947 ± 319.5 ppm), followed by magnesium (3075.9 ± 1357 ppm) and sodium (756.3 ± 478 ppm). The water-soluble vitamins B1, B2, B3, B6, and C were below the detection limit in the samples. The rich concentration of essential minerals such as potassium, magnesium, iron and zinc in Ulva intestinalis makes it a promising novel food source. To the best of our knowledge, this is the first experimental study to examine the feasibility of using seaweed that is native to the UAE as a nutritional and sustainable food source in order to address the challenge of food security currently being faced by the country. Full article

The aim of this study was to evaluate the characteristics of macroalgae (Cladophora rupestris, Furcellaria lumbricalis, Ulva intestinalis) and microalgae (Arthrospira platensis (Sp1, Sp2), Chlorella vulgaris) extracts, including micro- and macroelement transition to extract, antioxidant, antimicrobial properties, the concentrations of chlorophyll (-a, -b), and the total carotenoid concentration (TCC). In macroalgae, the highest TCC and chlorophyll content were found in C. rupestris. In microalgae, the TCC was 10.1-times higher in C. vulgaris than in Sp1, Sp2; however, the chlorophyll contents in C. vulgaris samples were lower. A moderate negative correlation was found between the chlorophyll-a and TCC contents (r = −0.4644). In macroalgae extract samples, C. rupestris and F. lumbricalis showed the highest total phenolic compound content (TPCC). DPPH antioxidant activity and TPCC in microalgae was related to the TCC (r = 0.6191, r = 0.6439, respectively). Sp2 extracts inhibited Staphylococcus haemolyticus; C. rupestris, F. lumbricalis, U. intestinalis, and Sp2 extracts inhibited Bacillus subtilis; and U. intestinalis extracts inhibited Streptococcus mutans strains. This study showed that extraction is a suitable technology for toxic metal decontamination in algae; however, some of the desirable microelements are reduced during the extraction, and only the final products, could be applied in food, feed, and others. Full article

Macroalgae can directly restrict the growth of various phytoplankton species by releasing allelopathic compounds; therefore, considerable attention should be paid to the allelopathic potential of these organisms against harmful and bloom-forming cyanobacteria. The main aim of this study was to demonstrate for the first time the allelopathic activity of Ulva intestinalis on the growth, the fluorescence parameters: the maximum PSII quantum efficiency (F_v/F_m) and the effective quantum yield of PSII photochemistry (ΦPSII), the chlorophyll a (Chl a) and carotenoid (Car) content, and the microcystin-LR (MC-LR) and phenol content of three bloom-forming cyanobacteria, Aphanizomenon sp., Nodularia spumigena, and Nostoc sp. We found both negative and positive allelopathic effects of U. intestinalis on tested cyanobacteria. The study clearly showed that the addition of the filtrate of U. intestinalis significantly inhibited growth, decreased pigment content and F_v/F_m and ΦPSII values of N. spumigena and Nostoc sp., and stimulated Aphanizomenon sp. The addition of different concentrations of aqueous extract also stimulated the cyanobacterial growth. It was also shown that the addition of extract obtained from U. intestinalis caused a significant decrease in the MC-LR content in Nostoc sp. cells. Moreover, it the phenol content in N. spumigena cells was increased. On the other hand, the cell-specific phenol content for Aphanizomenon sp. decreased due to the addition of the filtrate. In this work, we demonstrated that the allelopathic effect of U. intestinalis depends on the target species’ identity as well as the type of allelopathic method used. The study of the allelopathic Baltic macroalgae may help to identify their possible role as a significant biological factor influencing harmful cyanobacterial blooms in brackish ecosystems. Full article