Search Results (679)

Comprising multiple microorganisms, the microbiota plays a crucial role in regulating the immune system and maintaining homeostasis. The influence of genetic and environmental factors causes the composition of the microbiota to change throughout life, which is called the plasticity of the microbiota. A eubiotic microbiota promotes the immune response, reducing the risk of inflammation and diseases such as IBD and cancer. The Mediterranean diet is of fundamental importance for a healthy microbiota. On the contrary, Western diets lead to microbiota dysbiosis and inflammation. Microalgae, and, in particular, their derivatives, show promise and relevance in the search for potential anti-inflammatory and antioxidant biomolecules. This review focuses on the correlation between microbiota, nutrition, immunity and microalgal derivatives, highlighting how these may be a potential innovative therapeutic strategy for the management of chronic inflammatory diseases. Full article

In recent years, research and development in the field of green extraction of bioactive compounds from plants has intensified. This increased focus is driven by market trends, environmental concerns, and consumers’ growing interest in natural and healthy ingredients, as well as bioactive compounds. This development aligns with a global trend toward more sustainable use of natural resources. In this context, macroalgae have been recognized as valuable sources of bioactive compounds with various health benefits. These molecules include proteins, fatty acids, vitamins, and pigments. Phycobiliproteins (PBPs) are pigments and metabolites of particular interest that can be extracted from microalgae. This group of colored proteins, mainly present in cyanobacteria and red algae, is known to have a wide range of potential applications. However, conventional methods for extracting PBPs, such as homogenization, maceration, and freezing, are time-consuming and energy-intensive, often producing unsatisfactory yields. As a result, new extraction technologies have been developed, including ultrasound-assisted extraction, ionic liquid extraction methods, and the use of natural deep eutectic solvents. This review summarizes existing green processes for extracting and purifying PBPs, with the aim of enabling feasible and sustainable valorization of algae. Specifically, it covers various extraction and purification techniques of PBPs, as well as the effects of environmental growth conditions on the production of these metabolites. It also highlights the biological and pharmacological activities of PBPs and explores their potential applications in the food, cosmetic, and biomedical sectors. Full article

Spirulina and Chlorella are nutrient-rich microalgae widely consumed as dietary supplements; however, their high biosorption capacity raises concerns regarding the accumulation of environmental contaminants. This study analyzed 52 commercially available Spirulina and Chlorella products (29 conventional, 23 organic) to assess the co-occurrence of heavy metals and pharmaceutical residues, as these two classes of contaminants represent distinct yet complementary indicators of environmental pollution—heavy metals reflect long-term inputs from natural and industrial sources, while pharmaceuticals signal more recent contamination linked to human activity and wastewater discharge. To the best of our knowledge, this is the first study to investigate the presence of pharmaceutical residues—including cardiovascular drugs, antidepressants, antibiotics, and sulfonamides—in both conventional and organic formulations of microalgae-based dietary supplements. The analyses were performed using Inductively Coupled Plasma Mass Spectrometry and liquid chromatography coupled to tandem mass spectrometry. Aluminum, manganese, strontium, and zinc were the dominant trace elements. All samples complied with EU regulatory limits for toxic metals. More importantly, a wide range of pharmaceutical residues was detected in the supplements. Caffeine was the most frequently found compound, followed by metronidazole, carbamazepine, benzocaine, and tramadol. Particular concern is raised by the calculated TWI (% of tolerable weekly intake) for aluminum. Principal Component Analysis revealed significant compositional differences between Spirulina and Chlorella products, with vanadium notably elevated in conventionally cultivated Spirulina. Surprisingly, no significant differences were observed between organic and conventional products within each algal type. Our findings provide a novel contribution to the field by highlighting the presence of pharmaceutical residues in microalgae-based supplements and addressing a critical knowledge gap concerning potential chronic exposure to these contaminants through dietary intake. Full article

Raceway ponds would allow the sustainable production of algal biomass because of their lower cost. However, for successful cultivation, the target organism needs to prevail despite unavoidable contamination by environmental strains. The development of efficient methods to control cyanobacterial proliferation is thus highly desirable. With the aim to identify new cyanobactericidal substances, a set of natural compounds was screened for the ability to inhibit the growth of a model cyanobacterial strain, Synechococcus elongatus PCC 6301. Three compounds, namely hydroquinone, juglone and plumbagin, were found to be active in the 10⁻⁶ to 10⁻⁴ M range. Activity was confirmed on a panel of 10 other cyanobacteria that showed different sensitivity, with concentrations causing 50% growth inhibition varying up to 2 orders of magnitude. Co-cultivation experiments showed that the growth of Microcystis aeruginosa PCC 7941 was almost completely suppressed at quinone concentrations at which that of Tolypothrix PCC 7601 was substantially unaffected. Juglone and plumbagin in the micromolar range also exerted toxic effects on eukaryotic microalgae, bacteria and yeast, whereas the growth of higher plants was affected only at higher concentrations. In the case of juglone, activity was lost with time after being dissolved, allowing water discharge/recycling. The results point at the aromatic 1.4-quinone/diol ring as a lead moiety for the development of chemicals to help maintaining monospecificity of microalgae cultures. Full article

Engineered nanoparticles are increasingly released into aquatic environments, raising concerns about their effects on primary producers. Titanium dioxide nanoparticles (TiO₂ NPs), one of the most widely used nanomaterials, are frequently detected at low concentrations in surface waters. Here, we investigated the impact of environmentally relevant TiO₂ NP concentrations (1.1–17.6 µg/L) on the freshwater microalga Chlorella vulgaris by combining standardized growth inhibition bioassays with transcriptional analysis of photosynthesis-related genes. Cultures were exposed for 72 h following OECD TG 201, and cell density, growth factor (GF), and specific growth rate (µ) were determined to validate bioassay reliability. Gene expression of six photosynthetic genes (atpB, psaA, psaB, psaD, psbA, and rbcL) was quantified by RT-qPCR and normalized against 18S rRNA. Statistical analyses included Shapiro–Wilk and Levene’s tests, followed by one-way ANOVA with Bonferroni or Dunnett T3 post hoc corrections. The results showed a hormetic growth response, with stimulation at intermediate NP concentrations and no inhibition at the highest dose. At the molecular level, rbcL was significantly repressed at 1.1–4.4 µg/L, while psaA and psaD were upregulated at 8.8–17.6 µg/L, indicating compensatory reinforcement of photosystem I. These divergent transcriptional trajectories demonstrate that molecular endpoints reveal sublethal effects not evident from cell counts alone. Overall, this study highlights the potential of photosynthesis-related genes as early biomarkers for detecting nanoparticle-induced stress in aquatic primary producers. Full article

This study evaluated the ability of microalgae to produce carbonate minerals through CO₂ uptake, in comparison with abiotic, direct chemical synthesis through CO₂ absorption. A freshwater microalga (Synechococcus elongatus) isolated from garden soil in East Anglia, UK, was cultivated under laboratory conditions with CO₂ injection to generate a bicarbonate-rich aqueous solution, in which Fe²⁺, Mg²⁺, and Ca²⁺ ions were added to facilitate carbonate formation. Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD) analyses revealed distinct morphologies and mineral types. The algae-based process precipitated calcite, siderite, magnesite, and dolomite, whereas the abiotic process yielded, respectively, calcite, siderite, high-Mg calcite and nesquehonite. Biogenic minerals were finer and more morphologically diverse than their abiotically formed counterparts. The results indicated that microalgae produced 0.21 mol/L of calcium carbonate, compared to 0.51 mol/L obtained through abiotic CO₂ sequestration, and a comparable yield of about 0.25 mol/L reported for Sporosarcina pasteurii-induced precipitation. Acid resistance tests showed that algae-induced minerals had similar or improved resistance to acidic conditions compared to minerals formed through abiotic CO₂ consumption. Overall, despite slower kinetics, algae-induced carbonate precipitation offers advantages for soil stabilization by biocementation in the context of environmental sustainability, climate change mitigation and circular economy. Full article

Microalgae and cyanobacteria, as versatile photoautotrophic microorganisms, hold significant promise for mitigating soil and water pollution—particularly the removal of pesticides. This review examines their multifaceted roles in pesticide biodegradation, emphasizing how their metabolic capabilities simultaneously reduce environmental toxicity, enrich soil properties, and support beneficial microbiota. Cultivation in wastewater treatment systems further highlights their potential for cost-effective bioremediation, as these microbes degrade pesticides, recycle nutrients, break down organic pollutants, and generate biomass with value-added applications. Despite these advantages, implementing large-scale processes remains challenging. Key hurdles include optimizing growth parameters, preventing contamination, improving harvest efficiency, and designing robust bioreactors. Addressing these complexities demands interdisciplinary collaboration in strain selection, metabolic engineering, and process intensification. By capitalizing on microalgae and cyanobacteria’s adaptability and metabolic flexibility, we can develop more sustainable management strategies that reduce reliance on chemical inputs, foster soil health, and contribute to long-term ecological restoration. Ultimately, these microorganisms have the potential to reshape environmental stewardship by combining economic viability with broad-scale ecological benefits. Full article

The Ecuadorian Tropical Andes serve as vital biodiversity hotspots, crucial for hosting and preserving unique endemic species. While numerous taxonomic groups within these hotspots have been extensively studied, microalgae remain relatively unknown. This study aimed to document the microalgal diversity of Tropical Andean lakes in Ecuador and its relationship with abiotic environmental factors. Water samples were collected from 28 lakes throughout 10 conservation areas, spanning different altitudes in the Ecuadorian Tropical Andes, along with water physical/chemical data. A total of 92 microalgal genera were identified, spanning Bacillariophyta, Chlorophyta, Glaucophyta, Ocrophyta, Cyanophyta, and Euglenophyta. Lakes such as Rodeococha, Anteojos, Chinchillas, Toreadora, Magdalena, and La Mica exhibited the highest richness of microalgal genera. A positive association between temperature and the majority of microalgal phyla, except Glaucophyta, was observed. On the other hand, negative correlations were observed between total dissolved solids and water conductivity with microalgal biodiversity. Additionally, all groups displayed negative associations with pH, except Glaucophyta. The Jaccard similarity index was low among lake communities in agreement with the uniqueness of genera found in some lakes. This study represents a fundamental baseline for future investigations into Ecuador’s microalgal diversity and its relationship with abiotic environmental factors in the delicate freshwater ecosystems of Tropical Andean lakes. Full article

Marine bacteria possess significant potential for numerous applications including environmental remediation, creation of natural products and medicines, agriculture, and various industrial sectors. In this study, the diversity of bacterial populations in the seawater at the nearshore S1 station which is a frequent red-tide occurrence area in the East China Sea, was characterized using 16S rRNA gene amplicon sequencing analysis. The three predominant phyla in the bacterial communities were identified as Proteobacteria, Actinobacteria, and Bacteroidetes, with the families Rhodobacteraceae, Mycobacteriaceae, and Flavobacteriaceae as the dominant groups, respectively. The bacterial community composition at the S1 station significantly differed from those of the other five investigated coastal sites, and demonstrated its own unique taxonomic associations with the Rhodobacteraceae as the keystone species. Functional prediction through KEGG and MetaCyc analyses revealed the presence of an L-tryptophan biosynthesis pathway responsible for indole-3-acetic acid (IAA) production. By using the targeted isolation of cultivable bacterial strains, a novel red-pigmented bacterium, designated S1-TA-50, which produced IAA metabolites, was recovered from the S1 station. It was identified as a potential novel species within the genus Sulfitobacter in the family Rhodobacteraceae. This bacterium demonstrated notable antibacterial activity against four model pathogenic strains and also acted as a new microalgae growth-promoting bacterium with substantial IAA production after bacterial culture optimization. This study contributes to the accumulation of scientific knowledge regarding the dynamics of marine bacterial ecosystems in nearshore eutrophic environments and facilitates a better understanding of phycosphere bacterial roles in coastal ecosystems, as well as the comprehensive utilization of microbial resources. Full article

Antiretrovirals (ARVs) present variable toxicity to aquatic organisms. This study reviewed the literature from the Web of Science, Scopus, and PubMed to evaluate ARV ecotoxicity, focusing on aquatic models. Inclusion criteria were studies using ARVs as test substances with toxicity data on aquatic organisms. Quality assessment followed the CRED method, and environmental risk was evaluated via risk quotients (RQs) using the ERA tool. Efavirenz emerged as the most toxic ARV, with EC50 values of 0.011 mg/L (Chlorococcum infusionum) to 0.034 mg/L (Raphidocelis subcapitata), causing growth inhibition, photosynthesis reduction, and oxidative stress. Tenofovir showed lower toxicity, with EC50 values above 300.0 mg/L (Biomphalaria glabrata) and 111.82 mg/L (Artemia salina). Other ARVs, including Lamivudine and Zidovudine, displayed moderate toxicity (EC50 3.013–5.442 mg/L in microalgae). Main effects observed included oxidative damage, altered enzyme activity (catalase and NADH-cytochrome C oxidoreductase), reduced growth and photosynthesis, and bioaccumulation in aquatic plants like Lemna minor. Efavirenz also showed synergistic toxicity when combined with other ARVs. These findings indicate that ARVs, particularly highly toxic compounds such as Efavirenz, pose significant ecological risks, emphasizing the importance of proper disposal and remediation strategies to protect aquatic ecosystems. Full article

To address the greenhouse effect and environmental pollution stemming from fossil fuels, the development of new energy sources is widely regarded as a critical pathway toward achieving carbon neutrality. Microalgae, as a feedstock for third-generation biofuels, have emerged as a research hotspot for producing biojet fuel due to their high photosynthetic efficiency, non-competition with food crops, and potential for carbon reduction. This paper provides a systematic review of technological advancements in the catalytic hydrogenation of microalgal oil for biojet fuel production. It specifically focuses on the reaction mechanisms and catalyst design involved in the hydrogenation–deoxygenation and cracking/isomerization processes within the Oil-to-Jet (OTJ) pathway. Furthermore, the paper compares the performance differences among various catalyst support materials and between precious and non-precious metal catalysts. Finally, it outlines the current landscape of policy support and progress in industrialization projects globally. Full article

Chitin, one of the most abundant natural polysaccharides, has gained increasing attention for its structural diversity and potential in biomedicine, agriculture, food packaging, and advanced materials. Conventional chitin production from crustacean shell waste faces limitations, including seasonal availability, allergenic protein contamination, heavy metal residues, and environmentally harmful demineralization processes. Chitin from fungi and microalgae provides a sustainable and chemically versatile alternative. Fungal chitin, generally present in the α-polymorph, is embedded in a chitin–glucan–protein matrix that ensures high crystallinity, mechanical stability, and compatibility for biomedical applications. Microalgal β-chitin, particularly from diatoms, is secreted as high-aspect-ratio microrods and nanofibrils with parallel chain packing, providing enhanced reactivity and structural integrity that are highly attractive for functional materials. Recent progress in green extraction technologies, including enzymatic treatments, ionic liquids, and deep eutectic solvents, enables the recovery of chitin with reduced environmental burden while preserving its native morphology. By integrating sustainable sources with environmentally friendly processing methods, fungal and microalgal chitin offer unique structural polymorphs and tunable properties, positioning them as a promising alternative to crustacean-derived chitin. Full article

Microalgae are considered to be a dual solution for CO₂ fixation and biogas slurry purification due to their high photosynthetic efficiency and strong environmental adaptability. However, their application is constrained by the low solubility of CO₂ in the solution environment, which restricts microalgal growth, resulting in low biomass production and poor slurry purification efficiency. In this study, we developed MgFe layered double hydroxide (LDH) that spontaneously combined with Chlorella pyrenoidosa to help it concentrate CO₂, thereby increasing biomass yield and purification capacity for food waste biogas slurry. The prepared MgFe-LDH exhibited a typical layered structure with a CO₂ adsorption capacity of 4.44 mmol/g. MgFe-LDH and C. pyrenoidosa carried opposite charges, enabling successful self-assembly via electrostatic interaction. Compared with the control, the addition of 200 ppm MgFe-LDH increased C. pyrenoidosa biomass and pigment content by 36.82% and 63.05%, respectively. The removal efficiencies of total nitrogen, total phosphorus, and ammonia nitrogen in the slurry were enhanced by 20.04%, 31.54% and 14.57%, respectively. The addition of LDH effectively alleviated oxidative stress in C. pyrenoidosa and stimulated the secretion of extracellular polymeric substances, thereby enhancing the stress resistance and pollutant adsorption capabilities. These findings provided a new strategy for the industrial application of microalgal technology in CO₂ fixation and wastewater treatment. Full article

Lipids obtained from microalgae have recently received significant attention from the energy and food industries. Microalgae are promising alternatives and are more sustainable sources of lipids for the food industry, which faces a growing demand for food and increased environmental awareness among consumers. This study provides a bibliometric review of research articles published between 2019 and 2024 with the aim of understanding the future trends and tendencies of the applications of microalgal lipids in the food industry. A thorough assessment of 255 articles retrieved from the Scopus database showed an apparent decrease in the number of publications per year within the analyzed timeframe. The predominant focus has been basic research conducted on a lab-scale using chlorophytes (green algae) to optimize lipid production by modulating physicochemical cultivation parameters (i.e., nutrient availability, temperature, light, and pH). Lipids were mainly extracted using the Bligh and Dyer or Folch methods, quantified gravimetrically, and characterized using gas chromatography coupled to mass spectrometry. Publications referring to polyunsaturated fatty acids, such as omega-3 and omega-6, were the most abundant. The results emphasized the significance of microalgae as a promising biotechnological platform for the production of lipids within the food industry. Full article

Food processing wastewater (FPW) poses significant environmental risks due to its high nutrient load yet offers untapped potential as a low-cost feedstock for high-value compound production. This review critically evaluates the valorization of FPW for astaxanthin production through the mixotrophic fermentation of microalgae. Key microalgal species (e.g., Haematococcus pluvialis and Chromochloris zofingiensis) effectively remediate nutrients (nutrients removal of up to 100%) while synthesizing astaxanthin under stress-inducing conditions, such as nutrient starvation, salinity, and oxidative stress. Advanced strategies, such as two-stage cultivation, nutrient profile adjustment, and microbial co-cultivation, which could enhance astaxanthin yields and wastewater treatment efficiency were reviewed comprehensively. The resulting astaxanthin-rich biomass demonstrates multifunctional benefits in animal feed, improving meat quality, immunity, growth, and shelf life. However, this review identifies some challenges, including wastewater management risks, low digestibility of microalgae biomass, and astaxanthin instability during feed processing, which should be addressed properly in real-world applications. This integrated approach aligns with circular bio-economy principles, transforming FPW from an environmental liability into a resource for sustainable biotechnology. Full article