Search Results (1,177)

Algae extracts have emerged as a sustainable and eco-friendly alternative to synthetic dyes and functional additives in the textile industry, particularly for dyeing and functionalizing of cotton fabrics. Herein, two types of water-soluble algae extracts from Arthrospira platensis and Porphyridium cruentum were characterized in terms of thermal, structural, and functional properties and used as dye and/or functional agents. Cotton samples were pre-treated with chitosan and alum mordants and compared with commercially treated cationic cotton. The algae extracts were applied through the exhaust method, with variations in temperature, pH, liquor ratio, temperature rise gradient, and extract percentages. The resulting colours, assessed through CIE L*a*b* coordinates and K/S values using UV–Vis spectroscopy, displayed green and pink coloration, with commercial cationic cotton exhibiting more intense colours. Colour fastness measurements were also performed on functionalized cotton fabrics. The water-based algae extracts and functionalized samples were additionally characterized for functional features, displaying an antioxidant activity exceeding 60% (68.13 ± 3.60 and 60.76 ± 1.18, for A. platensis and P. cruentum, respectively). This work highlights their dual role in providing both aesthetic dyeing and functional enhancement of cotton. By using renewable marine resources and eco-friendly water-based processes, this approach supports the development of greener, more sustainable textile technologies. Full article

Green synthesis of nanoparticles has become one of the most popular research areas in recent decades due to its environmentally friendly nature and the minimization of harmful chemical by-products. This review focuses on the mechanism of palladium nanoparticle (PdNP) biosynthesis using bacteria, fungi, algae, and plants, and their potential biological activities, such as antibacterial, anticancer, antioxidant, and other properties, with the aim of their further biomedical applications. The role of various biomolecules in these processes is also discussed. Full article

Raphidiopsis raciborskii (formerly Cylindrospermopsis raciborskii) is a bloom-forming cyanobacterium that employs the production of toxins and other secondary metabolites as a competitive and allelopathic strategy. This study evaluated the effects of exudates from R. raciborskii cultivated under three nitrogen-to-phosphorus (N:P) ratios on the photosynthetic performance of Limnothrix sp. (cyanobacterium), Chlorella sp. (green algae), and Raphidocelis subcapitata (green algae), using pulse-amplitude-modulated (PAM) fluorometry. Rapid light curves (rETR) obtained under different N:P ratios and across the three target species exhibited similar response patterns. Likewise, effective quantum yield (ΦPSII), regulated (Y(NPQ)) and non-regulated (Y(NO)) energy dissipation showed comparable profiles among treatments after 24 h of exposure. Overall, the results of the present study indicate that, within the 24 h exposure period and based on the fluorescence parameters measured, exudates produced by R. raciborskii under the tested nutrient conditions did not cause measurable alterations in the photosynthetic performance of the three evaluated species. Full article

Nitrogen (N) and phosphorus (P) are essential macronutrients for plant growth and major pollutants driving aquatic eutrophication. Microalgae represent a sustainable biological platform for nutrient recovery and circular utilization from wastewater; however, the molecular mechanisms governing efficient urea assimilation and its coordination with phosphorus uptake remain inadequately characterized. This study investigated how overexpression of the high-affinity urea transporter gene DUR3 enhances nutrient scavenging capacity in the model green alga Chlamydomonas reinhardtii. The DUR3-overexpressing line exhibited concentration-dependent growth responses to urea, showing significant promotion at low-to-moderate levels but inhibition at high urea concentration or under pure-urea conditions, where DUR3-overexpressing (DUR3-OE) was more severely inhibited than the wild-type (WT). Notably, the DUR3-OE consistently increased chlorophyll content and photosynthetic efficiency (Fv/Fm) under ammonium, urea, and mixed-N regimes. Under low-urea conditions, the total P content of the DUR3-OE was 8.8% higher and total N content was 4.3% higher than in WT (p < 0.05). Except in pure-urea medium, the engineered strains exhibited significantly increased total P accumulation and superior P recovery efficiency from the culture medium. Transcriptomic analysis revealed that DUR3 overexpression reprograms a coordinated regulatory network associated with N/P metabolism, photosynthesis, and carbon transport pathways. RT-qPCR validation confirmed significant upregulation of PMA2 (plasma membrane H⁺-ATPase), phosphate transporters (PTB3, PTB7), the inorganic carbon transporter HLA3, and photosynthesis-related genes, which was associated with improved nutrient assimilation and photosynthetic performance. These findings establish DUR3 as a key genetic target for engineering microalgae with optimized N-P co-uptake capacity, providing a robust molecular framework for developing high-efficiency algal strains for wastewater bioremediation and nutrient circular economy applications. Full article

The use of microalgae as a food source is limited by consumers’ dislike of their organoleptic traits, primarily the intense green color and bitter taste associated with high chlorophyll content. The eukaryotic microalgae Chlorella vulgaris can grow under heterotrophic conditions, providing the opportunity to cultivate chlorophyll-less strains. In this work we applied random mutagenesis for breeding chlorophyll-deficient C. vulgaris strains. Wild-type strain was UVC-radiated, and 12 colonies with changed pigmentation were selected. Based on phenotypic stability two mutants, M6 and M11, were selected for characterization of growth, pigment and biomass accumulation. Cultivation under photo-, mixo- and heterotrophic conditions revealed distinct phenotypes for the two mutants. M6 remained chlorophyll-deficient in all cultivation conditions tested, while chlorophyll was observed in M11 when grown under light. Under heterotrophic and mixotrophic growth conditions, both mutants were chlorophyll-deficient while biomass productivity, protein content, and amino acid composition remained similar to wild type. Characterization of the cellular ultrastructure of the wild type and mutants using cryo Focused Ion-Beam Scanning Electron Microscopy revealed that functional chloroplasts and thylakoid membranes were absent in the mutants. Our work demonstrates how a simple approach using UV mutagenesis and visual screening can provide novel strains of C. vulgaris with traits for improved consumer acceptance, without compromising the use of the algae biomass as a protein-rich food source. Full article

Urban water bodies serve as biodiversity hot spots in a human-influenced landscape. We studied the backwater “Alte Donau” (Vienna, Austria), which has been the subject of ongoing management and restoration efforts. We aimed to capture short-term variations in the planktonic and benthic algal community during a vegetation period with a specific focus on Gloeotaenium loitlesbergerianum with its primary distribution in tropical regions. In total, 196 algal taxa were identified, indicating a high and balanced species diversity. Although the waterbody is shallow and densely colonized by macrophytes, phytoplankton and microphytobenthos exhibited significant differences in composition, particularly in spring. Less pronounced differences during summer were probably caused by macrophyte harvesting combined with recreational activities. We found a clear seasonal pattern with spring characterized by blooms of Ochrophyta, followed by a shift towards green algae, Dinophyta, and Cyanobacteria during summer and autumn. We found high variability in spring samples, whereas summer and autumn samples showed increasing similarity. Temperature, silicate, and alkalinity were the primary environmental factors structuring algal community composition. G. loitlesbergerianum was detected during warmer months from May through October across a temperature range of 14 to 28 °C, with highest abundances >20 °C. Warmer water and altered nutrient regimes not only stress native populations but also promote the establishment of new species such as G. loitlesbergerianum, accelerating community shifts. Therefore, sustained monitoring, targeted macrophyte restoration, and effective nutrient management are crucial for preserving both water quality and biodiversity in such systems. Full article

To address pipeline blockages and corrosion caused by moss, this study evaluates the effectiveness of two treatments, Isothiazolinone (IS) and layered double hydroxide–sodium pyrithione (LDH-SPT) modified hydrophobic resin membranes, in preventing moss growth. Furthermore, we closely examined how IS works at a molecular level to stop moss growth. The sequencing results revealed that the predominant algae identified in the pipeline moss community was a norank species of Trebouxiophyceae, accounting for 75.79%. Tests show that IS has strong moss inhibition. It works at low doses (0.2%) and becomes even more effective as the concentration increases. Furthermore, IS remains highly effective at inhibiting moss within a modified hydrophobic resin membrane, but its corrosion resistance is poor. The LDH-SPT@IS composite modified hydrophobic resin membrane addresses the corrosion problem of using IS alone and still works very well at inhibiting moss. Finally, the mechanism of IS’s inhibition of moss was elucidated based on experiments and existing literature. It functions by disrupting moss cellular DNA structure and interfering with the mitochondrial electron transport chain. This research provides the basis for developing efficient, durable, and eco-friendly solutions to prevent pipeline corrosion and moss growth, paving the way for new technologies and materials. Full article

Microscopic green algae are active producers of beneficial compounds, particularly those containing nitrogen. However, the metabolism of nitrogen-containing compounds is diverse and depends on the conditions of the nitrogen source. As a result, the approach to studying the metabolism of nitrogen-containing compounds becomes more complicated. This work demonstrates the metabolic changes in the high-productive green algae Neochlorella semenenkoi IPPAS C-1210 under conditions of nitrogen starvation and subsequent reintake, using high-performance liquid chromatography–mass spectrometry (HPLC–MS) with ¹⁵N isotopic labeling. The presented results include semi-quantitative chromatography–mass spectrometric analysis for 17 amino acids, a metabolomic profile of over 40 isotopically labeled compounds, an assessment of metabolic flux via isotopic incorporation, and an analysis of cellular lipid composition under varying growth conditions. The findings indicate that this strain can utilize ammonium acetate as a nitrogen source, consuming nitrogen in the ammonium form. The degree of isotopic labeling in compounds often diverged significantly from their quantitative changes (concentrations and chromatographic peak areas), suggesting that isotopic analysis may offer advantages over purely quantitative analysis for biological systems. Furthermore, in vivo biological isotopic labeling is shown to assist in identifying compounds absent from standard mass spectrometric databases. Full article

The conversion of biogas into high-value chemicals for pharmaceutical, cosmetic, and nutraceutical markets offers an attractive alternative to conventional fossil-based production routes, enabling circular value chains with significant socio-economic impact. This study evaluated the valorization of biogas into osmolyte and carotenoid compounds with market prices ranging from 1000 to 7000 $·kg⁻¹. Specifically, an algal–methanotrophic co-culture operated under saline conditions, preventing external microbial contamination and stimulating osmolytes and carotenoids, was assessed for its capacity to simultaneously remove methane (CH₄) and carbon dioxide (CO₂), with efficiencies of 92 and 89%, respectively. while producing ectoine, hydroxyectoine, lutein, β-carotene, and astaxanthin. Shotgun metagenomic analyses identified the key microorganisms driving the process, predominantly alkaliphilic and halophilic green algae (Chlorella, Dunaliella) and cyanobacteria (Leptolyngbya), and halotolerant methanotrophs (Methylotuvimicrobium) and methylotrophs (Methylophaga). Metagenomics further revealed the presence of key metabolisms related to C1 utilization and biosynthetic genes associated with carotenoid and osmolyte production, confirming the metabolic potential of the consortium to convert biogas-derived carbon directly into high-value compounds. Overall, these results demonstrate the feasibility of an efficient, biologically driven bio-platform capable of transforming greenhouse gas-rich waste streams into economically relevant bioactive molecules, contributing to global priorities in sustainable biomass-to-biochemical innovation. Full article

Bacteria associated with marine macroalgae are considered a promising source for secondary metabolites and industrially significant enzymes. Amylases, which are commercially important enzymes mainly isolated from microorganisms, exhibit antibacterial, anti-inflammatory, anti-viral and antibiofilm activities. In this study, bacteria associated with the green macroalga Ulva fasciata were explored for amylase enzyme production, optimization and antibiofilm activity against marine biofilm-forming bacteria. A total of 12 amylase-producing bacterial strains were obtained from the alga. Among the strains, strain MD02 showed higher amylase activity (138.2 U mL⁻¹) and strong biofilm inhibitory activity (89.5% inhibition). Molecular identification of strain MD02 showed similarity with Bacillus sp. The parameters influencing amylase production were initially tested using the traditional approach (one factor) followed by a two-level full factorial design and central composite design combined with response surface methodology. Results of statistical optimization showed a higher amylase yield (307.1 U mg⁻¹) at pH 7.5, 0.75% inoculum and 0.7% glucose. This study advances our knowledge of the significance of Ulva-associated marine bacteria as a source of amylase enzymes and an effective biofilm control agent. Overall, this study highlights the potential significance of marine-algae-associated bacteria for enzyme production and demonstrates the feasibility of cost-effective amylase enzyme production using low-cost substrates. Full article

This study selected the typical eutrophication associated algae species Chlorella pyrenoidosa and Microcystis aeruginosa, from which alginate-like expolymers (ALEs) were extracted. Their composition, structural characteristics, and potential as biofertilizers were systematically analyzed. Results indicate that both C. pyrenoidosa-ALE (Cp-ALE) and M. aeruginosa-ALE (Ma-ALE) primarily comprise proteins and polysaccharides as functional components. Cp-ALE exhibited higher extraction yields (35.34 ± 4.32 mg·g⁻¹ VSS, volatile suspended solids) and richer growth-promoting constituents such as tryptophan, while Ma-ALE demonstrated higher aromaticity in its structure. Pot experiments further demonstrated that both ALEs exhibited a “low-concentration promotion, high-concentration inhibition” effect on ryegrass growth: at the optimal concentration (1:10,000), Cp-ALE and Ma-ALE increased ryegrass dry weight by 61.2% and 59.8%, respectively, with no significant difference compared to the algal whole-cell fertilizer (CF). This study has established a simple, environmentally friendly pathway for resource utilization of microalgal waste. Extracting ALEs effectively preserves plant-promoting components within microalgae, providing not only a sustainable solution for high-value utilization of eutrophication associated algae, but also a viable pathway for green agriculture and circular economic development. Full article

Phytochelatin synthases (PCSs) are pivotal enzymes in heavy metal detoxification, yet also implicated in sulfur homeostasis and redox regulation. In this study, we report the molecular and functional characterization of the PCS gene from the green alga Scenedesmus acutus (SaPCS), comparing wild-type and chromium-tolerant strains of this microalga. RT-qPCR, immunoblotting and mass spectrometry analyses revealed that SaPCS expression and protein abundance are primarily regulated by sulfur availability rather than by chromium stress. Two protein isoforms (~70 kDa full-length and ~34 kDa truncated) were detected, both more abundant in the chromium-tolerant strain than the wild-type and responsive to sulfur availability. Furthermore, three alternatively spliced transcript variants (SaPCSa, SaPCSb, SaPCSc) lacking the C-terminal domain coding region but retaining a functional or partially disrupted N-terminal catalytic domain were identified, contributing to the post-transcriptional diversification of PCSs. Mass spectrometry analyses showed negligible phytochelatin production in response to chromium treatment, indicating that detoxification of this metal in S. acutus relies mainly on glutathione (GSH) conjugation and the ascorbate–GSH antioxidant cycle. Overall, these results suggest that SaPCS may promote chromium tolerance by modulating sulfur and redox metabolism rather than by driving phytochelatin accumulation, highlighting the remarkable functional plasticity of PCSs in algal stress responses. Full article

Macroalgae are essential components of marine ecosystems, supporting biodiversity, primary productivity, and the functioning of coastal habitats. In the northeast Atlantic Macaronesian archipelagos (Azores, Madeira, Selvagens, Canary Islands, Cabo Verde), they hold significant ecological and economic value and have recently emerged as key indicators of environmental change. This oceanic region faces increasing pressure from multiple stressors, including climate change, invasive species, habitat degradation, and other anthropogenic impacts, driving shifts in coastal ecosystems and the simplification of structurally complex habitats such as marine forests. To assess the current state of knowledge on Macaronesian macroalgae and identify gaps relevant to conservation and management, we conducted a systematic literature review following PRISMA guidelines. Our results show strong but uneven foundational knowledge, with the Azores and Canary Islands accounting for roughly 80% of publications. Research is dominated by fundamental studies in ecology and taxonomy, while applied research (e.g., resource exploitation, aquaculture, toxicology, and climate-change impacts) remains limited. Red algae and a few dominant orders (Ceramiales, Fucales, Dictyotales) are well represented, whereas green algae and less conspicuous taxa are understudied. Future research should expand geographic coverage, broaden taxonomic scope using molecular tools, strengthen applied research, standardize monitoring frameworks, and align scientific output with management needs. Full article

Achieving environmentally friendly, green, and non-toxic marine antifouling has long been a development goal of the modern coatings industry. However, in complex marine environments, non-toxic or low-toxic antifouling coatings often have a significantly reduced service life. Therefore, achieving stable antifouling performance on a low-toxic basis has always been a goal in this industry. By using fluorocarbon resin with low surface energy and spraying a well-mixed blend of alkaline earth metal oil-absorbing nanowires and nano zinc oxide particles that is under high pressure, half-embedded into the resin, and infiltrated with alkanes, the antifouling mechanism of these coatings is achieved by the slow release of oily components, creating a long-lasting liquid–liquid interface to separate biofouling from the coating. Thanks to this antifouling mechanism, the sample maintains a water contact angle of 100–110° for 42 days in static seawater, achieves over 98% resistance to bacterial adhesion, and reaches 99.9% resistance to protein and algae adhesion. This study provides a novel and promising solution for the strict implementation of low-toxic and harmless antifouling. Full article

Heat shock transcription factors (HSFs) play a crucial role in mediating responses to abiotic stresses. However, characterization of HSFs in macroalgae remains largely unexplored. In this study, a comprehensive analysis of HSFs was carried out in Saccharina japonica. A total of sixteen SjHSFs were identified. Phylogenetic analysis revealed that HSFs from brown algae form a distinct clade, separate from those from red algae, green algae, moss, and Arabidopsis thaliana. The DNA-binding domain was found to be highly conserved among SjHSFs. Analysis of cis-acting elements in SjHSF promoters suggested their potential roles in regulating growth, development, and stress responses. Tissue-specific expression profiles revealed differential expression of SjHSFs across various tissues of S. japonica. Under abiotic stresses, certain SjHSFs exhibited dynamic expression patterns, with particularly pronounced changes observed under high-temperature stress. We further employed a transcription factor-centered yeast one-hybrid (TF-Centered Y1H) to determine the motifs recognized by SjHSF-03. Seven conserved motifs were identified, and the distributions of these motifs were screened in the promoter regions of S. japonica genes involved in diverse biological processes and pathways. Notably, 23 heat shock protein (HSP) genes were among these motif-containing genes, and 21 out of these 23 SjHSPs were up-regulated under heat stress. Our results provide a solid foundation for future research on the specific functions of HSFs under different stress conditions and the regulatory mechanisms of HSF-mediated stress responses in S. japonica and other brown algae. Full article