Search Results (232)

Microalgae and cyanobacteria represent an emerging and sustainable source of bioactive compounds for the food, cosmeceutical, and pharmaceutical sectors. In this study, the potential of two microalgae-cyanobacteria consortia, consortium 1 (C1) consisting of Chlorella vulgaris and Arthrospira platensis, and consortium 2 (C2) consisting of Kamptonema sp., Nannochloropsis oculata, Tetraselmis suecica, and Chlorella vulgaris, as a source of bioactive peptides was evaluated. Firstly, protein extraction from both biomasses was optimized by testing different protein solubilization and precipitation pHs, with pH 10 and pH 5 providing the best results in terms of protein recovery in both cases. Selected protein extracts, with protein contents of 28.50 ± 2.69% (C1) and 8.46 ± 0.45% (C2), were further hydrolyzed with Alcalase, evaluating the impact of the incubation time on peptide release and the antioxidant capacity of hydrolysates. A total of 1 h of hydrolysis proved to be enough for antioxidant capacity increase. In addition, in silico hydrolysis of the proteins identified with Alcalase in C1 and C2 (data are available via ProteomeXchange with identifier PXD077201 and PXD077149 for C1 and C2, respectively) was evaluated, assessing the potential bioactivity of the peptides produced, more specifically their antioxidant capacity. Our findings demonstrate that both microalgae-cyanobacteria consortia are valuable sources of bioactive compounds with antioxidant capacity, with potential interest as functional ingredients for the food, cosmeceutical, and pharmaceutical industries. Full article

This work focuses on the production of biodiesel from Nannochloropsis sp. microalgae. The study compares the effectiveness of conventional methods, such as Soxhlet extraction and the Bligh and Dyer method with a non-conventional method that uses an ionic liquid as solvent for lipid extraction. The Bligh and Dyer method demonstrated superior efficiency with a lipid yield of 8.19% compared to Soxhlet extraction. Sample parameters were optimized in a maximum lipid yield of 18.29% at a sample volume of 91.9 mL, a duration of 7 min, and a power rate of 0.62 W. We further investigated the use of ionic liquids for lipid extraction from microalgae. We synthesized ionic liquids, and 1-(4 sulphonic acid) butyl-3-Methyl imidazolium hydrogen sulphate and 1-(4 sulphonic acid) butyl pyridinium hydrogen sulphate were characterized using FTIR, NMR and TGA. This method showed lipid extraction efficiency values of 10.7% and 0.402%. Subsequent transesterification of algal oil using 1-(4 sulphonic acid) butyl-3-Methyl imidazolium hydrogen sulphate yielded 19.82% biodiesel. FTIR analysis confirmed the presence of lipids and esters in the biodiesel, and the produced biodiesel met ASTM specifications, indicating its suitability for use as biofuel. Full article

Zeolites are naturally abundant, low-cost aluminosilicate minerals commonly found in sedimentary rock. The surface chemistry of zeolite can be modified via cationic surfactant loading, termed a surfactant-modified zeolite (SMZ), that can be used as an antimicrobial technology in water treatment processes. This raises the possibility that SMZs could be utilised to treat blooms of harmful algae and cyanobacteria; however, there is a lack of understanding of the toxicity of SMZs to non-target microorganisms, including non-problematic algae and cyanobacteria. To address this knowledge gap, this research investigates whether hexadecyltrimethylammonium-bromide (HDTMA-Br) SMZs are toxic to the cyanobacterium Synechococcus elongatus and the microalgae Chlorella vulgaris, Nannochloropsis oculata and Duniallela salina. The cells were exposed to natural zeolite, HDTMA-Br surfactant and HDTMA-Br SMZ for 24 h and analysed 2- and 26 h post-exposure via flow cytometry and imaging pulse amplitude modulated fluorometry. There was an overall trend of reduced cell density in the SMZ and surfactant treatments. The SMZ treatment reduced the effective PSII quantum yield (Y(II)) but increased the quantum yield of regulated energy dissipation for C. vulgaris. When exposed to the surfactant treatment, no Y(II) signals were detected from any species. We conclude that SMZs are toxic to non-target microorganisms, with resilience dependent upon cell wall structure. Full article

Background/Objectives: Microalgae are gaining increasing attention as sustainable sources of dietary lipids and other bioactive compounds; however, the relationship between microalgae lipid composition and physiological outcomes in vivo remains insufficiently understood. This study aimed to characterize antioxidant activity, total lipid content and fatty acid (FA) profiles of selected freshwater microalgae and to evaluate their dietary impact using Drosophila melanogaster as a whole-organism model. Methods: Four freshwater microalgal species (Chlorella vulgaris, Nannochloris limnetica, Scenedesmus communis, and Tetradesmus obliquus) were cultivated separately in 3N-BBM+V medium under controlled laboratory conditions. DPPH, FRAP and TPC were measured in microalgae methanolic extracts. Total lipids were extracted using a modified Breuer method and quantified gravimetrically. FA profiles were determined as fatty acid methyl esters by GC-FID. Freeze-dried microalgal biomass (3 mg/mL) was incorporated into standard D. melanogaster diet. Lifespan and body mass were assessed separately in females and males, as well as fecundity in general. Results: Total lipid content ranged from 17.3% to 28.1% of dry weight, with FA profiles dominated by C16 saturated, monounsaturated (omega-9), and omega-6 polyunsaturated fatty acids. Correlation analysis indicates that antioxidant properties of the studied microalgae are more closely linked to lipid fractions than to phenolic content. Dietary supplementation with microalgal biomass of three out of four microalgal species significantly extended median lifespan, particularly in males, without adverse effects on body mass or fecundity. Conclusions: These findings indicate that freshwater microalgae can serve as a physiologically safe dietary lipid source. D. melanogaster represents a suitable in vivo model for screening the nutritional potential of microalgal lipids. Full article

Despite the extensive literature on microalgal production, most studies focus on controlled laboratory-scale systems, resulting in a critical lack of confidence at industrial scale. This is further compounded by the frequently observed inconsistencies, with only modest increases achieved in operational scale. This work demonstrates the design, construction, and operation of a commercial-scale tubular photobioreactor and associated equipment for the production of algae using CO₂ derived from an industrial nickel refinery. The reactor was demonstrated by growing the species Nannochloropsis gaditana. Biomass concentrations of 1.0 to 1.3 g L⁻¹ were achieved with a productivity of 0.11 g L⁻¹ d⁻¹. Extrapolation to a 300-day production year showed that the reactor was capable of producing 541.2 kg algae and sequestering around 1 tonne of CO₂. A technoeconomic assessment showed that the total plant CAPEX was £583,905 and the OPEX was £98,196. Sales of algae alone showed poor economic performance. However, economic favourability is observed for species that contain phycocyanin pigment and yield a positive net present value within 4 to 7 years based on recovery yield. This work effectively provides reliable process data developed at scale that can be used to formulate business cases for further scale-up and expansion of algal production systems. This moves the technology a step closer to full-scale realisation and the potential for a net-zero, sustainable future. Full article

To change the saturated fatty acid composition of traditional cookies and enhance their functionality, corn oil-based emulsion gels were innovatively used as a substitute for butter. The study also investigated the impact of adding powder on the overall quality of cookies. Under optimal conditions comprising a 6:4 oil-to-water ratio, 3% gelatin concentration, and 0.1% grape seed polyphenol concentration, the prepared emulsion gel achieved an oil retention rate of 84.5%. Following the incorporation of the emulsion gel, the sensory score of the composite sample WZ significantly increased. The texture became softer, and a greenish-brown color, more acceptable to consumers, was developed. In vitro digestion analysis further revealed that the combined incorporation of Nannochloropsis gaditana powder and the emulsion gel reduced the RDS content from 59.6% to 54.0%,while increasing RS content to 25.8%, thereby effectively retarding the rate of in vitro starch digestion. This study utilized a corn oil-GSP/gelatin emulsion gel as a butter substitute in combination with microalgae incorporation, thereby achieving concurrent health enhancement and quality improvement of cookie products. The approach provides a feasible technical strategy and theoretical foundation for developing novel baked foods that exhibit favorable sensory properties and controlled starch digestion characteristics. Full article

This present study provides a comprehensive and novel assessment of Nannochloropsis sp. extracts as multifunctional ingredients for food applications, combining lipid profiling, nutritional quality indices, and antimicrobial activity. The extracts were obtained by ultrasound-assisted hydroethanolic extraction (90% EtOH solution; 20 kHz pulses of 30 s during 10 min). Nannochloropsis sp. biomass exhibited a high lipid content (36.6%), and GC-FID analysis of its extract revealed high concentrations of palmitic acid, palmitoleic acid, and eicosapentaenoic acid (EPA). Nutritional quality indices—including the index of atherogenicity (AI), the index of thrombogenicity (TI), and the hypocholesterolemic/hypercholesterolemic ratio (HH)—were favorable, and the health-promoting index (HPI) was high. Although the extract exhibited low antioxidant activity in ABTS, DPPH, and ORAC assays, it demonstrated inhibitory activity against Gram-negative (Yersinia enterocolitica, Escherichia coli, Salmonella enterica Serovar Enteritidis) and Gram-positive (Staphylococcus aureus, and Listeria monocytogenes) foodborne pathogens, with a minimal inhibitory concentration of 6.3–12.5 mg/mL. These findings highlight the novelty of positioning Nannochloropsis sp. extracts as multifunctional ingredients that couple favorable lipid nutrition with antimicrobial functionality, rather than as single-purpose bioactives. The results support their potential for application in healthy food formulations and shelf-life extension strategies. Full article

As primary producers in aquatic ecosystems, microalgae function not only as a natural source of nourishment for several economically important aquatic species but also as reservoirs of bioactive molecules. Microalgae can secrete exosome-like nanoparticles that transport functional biomolecules, such as proteins and nucleic acids, into the extracellular milieu, thereby mediating intercellular signaling and eliciting ecological or biomedical responses. Although plant-derived exosome-like nanoparticles have attracted attention for their utility in drug delivery and dermatology, the functional properties of microalgae-derived nanoparticles—particularly from species extensively applied in aquaculture—remain inadequately characterized. In this study, exosome-like nanovesicles were isolated from Nannochloropsis oculata (N-ELNs), a microalgal species widely used in aquaculture, and their skin-whitening potential was evaluated using the B16-F10 mouse melanoma cell model. The highest N-ELN yield was observed during the adaptation, exponential, and stationary growth phases. Uptake analyses confirmed the efficient internalization of N-ELNs by B16-F10 cells. Cell counting kit-8 assays indicated that N-ELNs exhibited no cytotoxic effects on melanoma cells or normal human dermal fibroblasts (HFF-1). Scratch wound healing assays revealed that N-ELNs exerted no significant effect on cellular migration. In B16-F10 cells, N-ELNs suppressed tyrosinase activity by downregulating Mitf and its downstream genes Tyr and Tyrp1, resulting in a substantial reduction in melanin synthesis (p < 0.05). The inhibitory effects of N-ELNs on melanin production, tyrosinase activity, and gene expression of Tyr, Tyrp1, and Mitf were comparable to those of the positive control, arbutin. Collectively, these findings suggest that N. oculata exhibits promising skin-whitening properties, providing a novel perspective for clinical applications and supporting the high-value utilization of the microalgae aquaculture industry. Full article

Arthrospira platensis and Chlorella vulgaris are popular commercialised microalgae due to their benefits and relatively easy large-scale cultivation. However, recent advances in biotechnology have revealed a new range of promising strains with industrial potential but limited current markets. To bridge the gap in the existing literature, this study provides a comprehensive and simultaneous biochemical characterisation within a unified analytical framework of six additional strains: Phaeodactylum tricornutum, Tetraselmis chuii, Nannochloropsis oceanica, Scenedesmus almeriensis, Tisochrysis lutea, and Skeletonema costatum. The analyses included macromolecular composition, amino acid and fatty acid profiles, and volatile organic compound composition. Key results identified P. tricornutum and T. chuii as high-quality protein alternatives, reaching protein concentrations of 31% and 41% (dw), respectively, with essential amino acid profiles (arginine and tryptophan) that match commercial standards. Additionally, specific carbohydrate and lipid strengths were identified: P. tricornutum showed a high carbohydrate content (37%), while N. oceanica exhibited elevated levels of palmitic, palmitoleic, eicosapentaenoic, and arachidonic acids, marking them as versatile candidates for nutritional applications. Finally, volatile organic compound analyses revealed distinct aroma profiles, highlighting the potential of less-exploited microalgal strains for the food and feed sectors. Full article

The use of human-edible materials like soy in animal feed raises several concerns, as it contributes to high greenhouse gas emissions and requires significant land and water use for agriculture. For this reason, research is exploring alternative ingredients rich in proteins like microalgae, which offer potential nutritional and environmental benefits. Species like Nannochloropsis are promising since their use for human consumption is very limited, making them non-competitive with human food. This article aims to formulate a poultry feed in which 30% of the crude protein from soybean meal is replaced by Nannochloropsis oceanica single-cell ingredients. Growth parameters have been evaluated in comparison with a diet based on soy protein. Additionally, the effect on meat quality was assessed by evaluating nutritional, texture, stability, and sensory parameters. Results showed that the microalgae diet caused a slight reduction in animal growth due to lower digestibility of the feed. Considering the quality parameters of the meat, no differences were found in terms of shelf life and physicochemical parameters, except for the color. The microalgae diet significantly increased the content of n-3 fatty acids and carotenoids in the meat. Finally, regarding sensory properties, the only change detected was in the amount of exudate. Full article

Integrating catalytic function with oxygen-carrying capability into bi-functional materials represents a promising strategy for reverse chemical looping pyrolysis (RCLPy), which utilizes a reduced metal oxide to improve the bio-oil quality through in situ hydrogen donation and deoxygenation. In this study, a systematic evaluation of two typical catalysts (CaO and ZSM-5) was conducted for the pyrolysis of microalgae Nannochloropsis sp. under RCLPy conditions. First, the effect of each catalyst on the pyrolysis behavior of microalgae was analyzed by Gaussian fitting of derivative thermogravimetric (DTG) curves. Second, gases evolved during thermogravimetric analysis (TGA) were monitored in real time using Fourier-transform infrared spectroscopy (FTIR) for detecting CO, CO₂, H₂O, and functional groups (e.g., C–C, C=C, C=O), and mass spectrometry (MS) for tracking nitrogen-containing compounds. Third, the composition of bio-oils produced under RCLPy conditions was examined by Gas Chromatography–Mass Spectrometer (GC–MS) analysis. The results demonstrate that the catalyst enhances the bio-oil quality by elevating the content of aromatics up to 41.9 area% and that of aliphatic hydrocarbons to 19.1 area%, respectively, while reducing the content of nitrogen-containing compounds to 3.8 area%. However, the elimination pathway of oxygen and nitrogen elements involves different mechanisms. These findings provide valuable guidance for the design of bifunctional oxygen carriers aimed at enhancing the quality of bio-oil derived from microalgae pyrolysis. Full article

Multi-product biorefineries, which transform biomass feedstocks into multiple valuable bio-based products, are pivotal for transitioning from a fossil-based economy to a sustainable circular bioeconomy. This work proposes a processing pipeline for fractionating the macrocomponents of Nannochloropsis oceanica, which can serve as a basis for multi-product microalgae biorefineries. It consists of high-pressure homogenization (1200 bar, 1 cycle) to permeabilize the cells, and sequential membrane processing (0.2 µm dia-microfiltration followed by 100 kDa ultrafiltration) and ethanolic extraction (60 mL ethanol/g dry weight, 1 h) to fractionate the disrupted biomass. This biorefinery resulted in four final fractions: (1) enriched in water-soluble proteins (39.0 ± 2.8% w/w proteins; 10.7 ± 0.8% w/w carbohydrates); (2) remaining soluble components (5.7 ± 0.4% w/w proteins; 4.3 ± 0.9% w/w carbohydrates); (3) lipid-rich extract (62.4 ± 5.8% w/w lipids); and (4) non-extracted components (11.8 ± 4.5% w/w lipids), with mass recovery yields of 23.2 ± 2.1%, 6.9 ± 1.0%, 10.6 ± 1.9%, and 60.4 ± 4.1%, respectively. The ultrafiltration protein selectivity was not optimal, despite yielding a 2.6 times more concentrated fraction. Lipid extraction yield (35–60%) and purity (56–68%) were highly affected by the water content of the microfiltration retentate. Overall, 10.0 ± 0.9% of the proteins, 9.7 ± 1.8% of the carbohydrates, and 42.4 ± 13.4% of the lipids of N. oceanica were recovered in fractions 1, 2, and 3, respectively. Full article

Microalgae can modify their metabolic pathways as a response to environmental stimuli such as light, temperature, salinity, and nutrient availability, which critically influence the synthesis of lipids and other biomolecules. While extensive studies have focused on the impact of these environmental variables on the accumulation of valuable compounds such as polyunsaturated fatty acids (PUFAs) and triacylglycerols (TAGs), information on the biosynthesis of specialized metabolites, including long-chain hydroxy fatty acids (LCHFAs), long-chain diols (LCDs), and long-chain alkenols (LCAs) is scarce. These metabolites are thought to contribute to the structural integrity of cell walls in certain microalgae, such as Nannochloropsis spp. (Eustigmatophyceae), where they make up a biopolymer known as algaenan. This study investigates how varying light intensities affect the production of LCHFAs, LCDs, and LCAs in Nannochloropsis oceanica over a 12 h light/dark cycle. Our findings provide insights into the lipid biosynthetic pathways in microalgae, revealing that light strongly drives the production of LCHFAs, whereas LCDs and LCAs are less light-dependent and show more variable responses to different light intensities. Full article

Microalgae have garnered increasing attention as promising sources of diverse natural anti-inflammatory compounds, including carotenoids, phenolics, and unsaturated fatty acids. In this study, we aimed to examine the anti-inflammatory properties of the methanol extract of Nannochloropsis sp. G1-5 (NG15), a strain of marine microalgae isolated from the southern West Sea of the Republic of Korea. Pigment and metabolite analyses revealed that the extract contained various carotenoids and polyunsaturated fatty acids alongside significant quantities of phenolic and flavonoid compounds, which are known to have anti-inflammatory activities. Cytotoxicity assays confirmed that the extract was non-toxic to RAW 264.7 macrophage cells at concentrations up to 1 mg/mL. Upon lipopolysaccharide (LPS) stimulation of the macrophage cells, the NG15 extract significantly inhibited nitric oxide (NO) production in a dose-dependent manner up to 81%. In addition, the NG15 extract reduced the expression of iNOS, COX-2, TNF-α, and IL-6 in the LPS-stimulated cells. These findings suggest that NG15 methanol extract exerts anti-inflammatory effects primarily through the suppression of NO generation without inducing cytotoxicity. Overall, these results underscore NG15 as a promising natural resource for the development of non-toxic and effective anti-inflammatory agents with potential applications in the biomedical and cosmeceutical industries. Full article

Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are essential omega-3 polyunsaturated fatty acids (n-3 PUFAs) with well-established health benefits. They occur primarily in marine resources, while their quantitative distribution within the glycerolipidome is rarely analyzed. Therefore, we investigated major commercial sources, including 12 microalgal species, the protist Schizochytrium sp., four fish species, and nine commercial n-3 supplements (fish, krill and Schizochytrium-derived “algal” oils) by high-performance thin-layer chromatography–gas chromatography–mass spectrometry (HPTLC–GC–MS). The class-resolved mapping of EPA and DHA revealed signature lipid profiles across all sources. In microalgae, 60–80% of EPA was localized in glycolipids, whereas in Schizochytrium and fish, >90% of DHA occurred in triacylglycerols. Krill oils exhibited phospholipid-rich profiles with ~70% of phosphatidylcholine-bound DHA. Nutritional indices also highlighted major differences: fish and fish oils showed favorable PUFA-to-saturated FA ratios (>0.45) and hypocholesterolemic-to-hypercholesterolemic ratios (>1), while Schizochytrium-based “algal” oils even surpassed these values. The microalgae Nannochloropsis granulata contained the highest EPA content in biomass form, combined with favorable nutritional indices. Beyond total n-3 content in relation to recommended daily intake values, the lipid-class distribution and nutritional indices should be considered decisive metrics for evaluating the health relevance of n-3 resources in the human diet. Full article