Search Results (176)

Limited research has been conducted on the potential and mechanisms of irrigating Suaeda salsa with wastewater and microalgae to improve saline–alkali land. This study used three irrigation treatments (freshwater, saline wastewater, and saline wastewater with microalgae) to irrigate S. salsa, and microalgae promoted the growth of S. salsa and increased soil nutrient content, increasing available nitrogen (4.85%), available phosphorus (44.51%), and organic carbon (24.05%) while alleviating salt stress through reduced soil salinity (13.52%) and electrical conductivity (21.62%). These changes promoted eutrophic bacteria while inhibiting oligotrophic bacteria. Bacterial community composition exhibited significant variations, primarily driven by soil pH, total nitrogen, and organic carbon content. Notably, rhizosphere bacteria showed enhanced functional capabilities, with increased abundance of salt stress resistance and nitrogen metabolism-related genes compared to original soil, particularly under saline irrigation conditions. Furthermore, microalgae addition enriched nitrogen metabolism-related gene abundance. These findings revealed the potential role of key bacteria in enhancing plant growth and the soil environment and highlighted the potential of applying S. salsa, wastewater, and microalgae for the synergistic improvement of saline–alkali land. Full article

The environment is undergoing a constant incorporation of new pollutants, which must be eliminated to avoid toxicity problems. Amoxicillin (AMX) is a widely used antibiotic today, and for this reason, it reaches natural media with the consequent environmental risk. Biosorption is an effective and environmentally friendly solution which can be used for the removal of AMX. In the present study, the properties of the living biomass of the microalga Chlamydomonas reinhardtii were studied to determine the capacity of this biomass to remove AMX. This biomass has demonstrated to have good qualities to remove AMX with a maximum capacity of 12.72 ± 0.57 mg g⁻¹. Light was an important factor in increasing the removal capacity of this living biomass by 35.2%. Although this antibiotic underwent spontaneous degradation (unaffected by light), the presence of the biomass increased the amount removed and the removal rate. The amount removed by this biomass in the presence of light was always higher than the amount lost by spontaneous degradation. The kinetics that best adjusted was pseudo-second order. Maximum removal was obtained at pH 6. A point of zero charge and Fourier transform infrared spectrometry were used to characterize the biomass and study the process. Full article

Microalgae are increasingly recognised as sustainable, nutrient-dense sources of bioactive compounds with broad health-promoting potential. Rich in carotenoids, phenolics, polyunsaturated fatty acids, phycobiliproteins, sterols, and essential vitamins, microalgae offer a promising foundation for functional foods targeting chronic disease prevention. This narrative review explores the nutritional profiles and biological effects of key species, including Spirulina (Limnospira platensis), Chlorella, Haematococcus, and Nannochloropsis. Scientific evidence supports their antioxidant, anti-inflammatory, immunomodulatory, antimicrobial, and metabolic regulatory activities, contributing to reduced risks of cardiovascular, metabolic, inflammatory, and neurodegenerative disorders. Special emphasis is placed on the synergistic benefits of consuming whole biomass compared to isolated compounds and the technological strategies, such as encapsulation, cell wall disruption, and nutrient optimisation, that enhance the bioavailability of microalgal bioactives. Furthermore, the environmental advantages of microalgae cultivation, such as minimal land and freshwater requirements, carbon sequestration, and wastewater bioremediation, highlight their role in the transition toward sustainable food systems. Despite challenges related to high production costs, sensory attributes, scalability, and regulatory approval, advances in biotechnology, processing, and formulation are paving the way for their broader application. Overall, microalgae represent next-generation bioactive sources that promote human health and environmental sustainability, positioning them as key players in future functional foods and nutraceuticals. Full article

Diclofenac, a nonsteroidal anti-inflammatory drug widely used worldwide, has been detected in waterbodies at concentrations ranging from ng L⁻¹ to µg L⁻¹. Although diclofenac is not a persistent compound, aquatic organisms may be exposed to this drug for extended periods due to its incorporation into the environment by continuous release from hospitals and municipal discharges. This study aimed to evaluate the toxic effects of diclofenac on the microalga Pseudokirchneriella subcapitata, the cladoceran Daphnia curvirostris, and zebrafish embryos (Danio rerio). Toxicity bioassays for the microalga were performed according to the OECD 201 protocol with diclofenac concentrations of 0, 6.25, 12.5, 25, 50, 75, and 100 mg L⁻¹. For the determination of acute toxicity in the cladoceran (48 h), concentrations of 0, 10, 20, 30, 40, 50, and 60 mg L⁻¹ were tested; in subchronic bioassays, the effect of the drug on the reproductive parameters of D. curvirostris was determined for 21 days with sublethal concentrations of 10.3, 14.4, 17.2, and 21.3 mg L⁻¹. Toxicity bioassays on zebrafish embryos were performed according to the OECD 236 protocol, using concentrations of 0, 1, 2, 4, 6, 8, and 10 mg L⁻¹ of diclofenac. The results confirmed the toxic effects of the drug. The IC₅₀ for the microalga was 16.57 mg L⁻¹, while the LC₅₀ for D. curvirostris and D. rerio was 32.29 and 6.27 mg L⁻¹, respectively. In the microalga, chlorophyll-a and carotenoids increased at a concentration of 3.62 mg L⁻¹ of diclofenac; however, chlorophyll-b decreased at the highest drug concentration (13.51 mg L⁻¹). Protein and lipid concentrations in P. subcapitata exposed to all concentrations were higher than in the control. Chronic diclofenac exposure did not affect the survival of D. curvirostris; however, the cumulative progeny and number of clutches significantly decreased, and the age of first reproduction was delayed at all drug concentrations. Protein concentration in D. curvirostris hatchlings was higher at all diclofenac concentrations; in contrast, the amount of lipids and carbohydrates decreased significantly. In D. rerio, the hatching rate decreased by 40, 51.6, and 80% at concentrations of 6, 8, and 10 mg L⁻¹ diclofenac, respectively, and exposure to the drug caused lethal effects such as coagulation at 24 and 48 hpf; sublethal effects such as edema and curved tail were also observed at concentrations of 2 to 10 mg L⁻¹, and the effects increased with increasing concentration up to 144 hpf. The results demonstrate the vulnerability of aquatic organisms to the toxic effects of diclofenac, suggesting that discharging it into water bodies should be regulated to prevent potential ecological impacts on the various trophic levels of freshwater biota. Full article

Catechins, renowned for their health benefits, have unexamined environmental impacts. This study assessed the toxicity of crude catechin and catechin hydrate on invertebrate larvae, plant, and microalgae. The survival rates of Daphnia magna Straus and Artemia salina L. were monitored every 24 h over a three-day period. The germination rate and radicle length of Lactuca sativa L. was measured every 24 h for four days. Inhibitory effects were evaluated in both freshwater and seawater cultures of Chlorella vulgaris Beijerinck, with cell density recorded every 24 h and yield inhibition calculated after 96 h. Results indicated that increasing catechin concentration and exposure duration decreased the survival rate of D. magna and A. salina. Daphnia magna was more sensitive to catechins than A. salina, with 24 h lethal concentration 50 (LC-50) values of 1174 µg/mL compared to 1895 µg/mL for crude catechin, and 54 µg/mL compared to 153 µg/mL for catechin hydrate. The germination rate and radicle length of L. sativa, along with the cell density of C. vulgaris, decreased with increasing catechin concentration, but remained higher even after prolonged exposure. At low catechin concentrations, C. vulgaris cell density exceeded control levels. This study demonstrates that catechins in aquatic environments can significantly impact ecosystems. At certain concentrations, catechins are toxic and potentially lethal to aquatic organisms. Conversely, at lower concentrations, catechins may promote microalgal growth, suggesting a fertilizing effect. Understanding these dynamics is crucial for maintaining the stability of aquatic ecosystems. Full article

Nannochloropsis oceanica and Chlorococcum amblystomatis exhibit significant potential for protecting skin cells from oxidative stress-induced metabolic dysfunctions, owing to their high bioactive lipid content. This study aimed to evaluate their cytoprotective effects on the ultraviolet A (UVA)-perturbed proteome of 3D-cultured skin fibroblasts, using high-throughput proteomics. Chlorococcum amblystomatis lipid extract promoted a reduction in UVA-induced cytochrome c oxidase subunit 4 isoform 1 and cell death protein 6 levels, alongside the restoration of ferritin light chain expression diminished by UVA. It downregulated the expression of ubiquitin-conjugating enzyme E2 and lactoylglutathione lyase, which were upregulated by UVA. Furthermore, the elevated superoxide dismutase [Mn] mitochondrial levels in the caspase-1 interactome emphasized the lipid extract’s role in mitigating oxidative stress-associated chronic inflammation by regulating caspase-1 activity. In addition to this notable redox balance-regulating and cytoprotective activity, conversely, the protein inflammation signaling mediated by UVA was regulated in terms of wound healing potential in the case of Nannochloropsis oceanica lipid extract. Following UVA radiation, it promoted the upregulation of complement component B, thrombospondin-1, MMP1, and fibulin-1. The results revealed that both lipid extracts effectively reversed the UVA-perturbed proteomic profile of fibroblasts, highlighting their therapeutic potential in protecting the skin from UV radiation. Full article

Fludioxonil is a widely used fungicide that is frequently used to combat fungal plant diseases. Consequently, excessive concentrations of fludioxonil may enter and accumulate over time in aquatic systems, harming (micro) organisms in several ways. Thus, it is of great importance to evaluate the potential toxic effects of fludioxonil using bioassays. In the present study, various in vitro assays were used to assess the possible effects of fludioxonil in human cells and aquatic microorganisms. For the investigation of the toxic effects of fludioxonil on freshwater microalgae, Scenedesmus rubescens and Dunaliella tertiolecta were exposed to various environmentally relevant concentrations of the fungicide for a period of 96 h. Fludioxonil at 50–200 μg L⁻¹ significantly limited the growth of both microalgae, especially in the first 24 h of the exposure, where inhibitions up to 82.34% were calculated. The toxicity of fludioxonil was further evaluated via the Microtox test, and the studied fungicide was found to be less toxic for the bacteria Aliivibrio fischeri. Regarding human cells, the fludioxonil’s toxic and cyto-genotoxic effects were assessed using the Trypan blue exclusion test and the Cytokinesis Block MicroNucleus (CBMN) assay. Cell viability in all fludioxonil-treated concentrations was similar to control values according to the results of the Trypan blue exclusion test. However, the CBMN assay was used and revealed that fludioxonil had genotoxic potential in higher concentrations and exerted cytotoxic activity against human lymphocytes. Specifically, only the highest dose of fludioxonil, i.e., 10 μg mL⁻¹, exerted genotoxic effects against human lymphocytes, whereas treatment with 0.5, 1, and 5 μg mL⁻¹ did not lead to statistically significant induction of micronuclei (MN) frequencies compared with the control culture. However, fludioxonil-mediated cytotoxicity was statistically significant, which was demonstrated by the decreased CBPI (cytokinesis block proliferation index) values in all cases except for the lowest dose, i.e., 0.5 μg mL⁻¹. Full article

Microalgae cultivation in wastewater is a promising strategy for reducing nutrient loads and generating biomass that can be further exploited. Although microalgae grown under such conditions are not suitable for high-value applications, the resulting biomass can still be valuable for uses such as biofuels, biofertilizers, or animal feed. In this study, Chlorella sorokiniana was cultivated in dairy wastewater and, to the best of our knowledge, for the first time in a spent effluent from gas fermentation, to assess its potential as a sustainable growth medium. Growth kinetics and biomass productivity were evaluated at different dilution ratios, and it was found that high concentrations of ammonium and hexanol in undiluted effluents were inhibitory, while an optimized 50:50 dilution led to the highest biomass accumulation (1.96 g L⁻¹) and productivity (0.5 g L⁻¹ d⁻¹) of C. sorokiniana. This strategy significantly reduced the nitrogen (100%), phosphate (100%), sulfate (68%), and carbon (61%) contents, demonstrating effective bioremediation activity. Furthermore, the fatty acid profile revealed an increased polyunsaturated fatty acid fraction, enhancing the potential of C. sorokiniana biomass as a feed supplement. Overall, contributing to the circular bioeconomy, this approach is scalable and cost-effective, reducing freshwater and chemical dependency in microalgae biomass production. Full article

Microalgae are microscopic unicellular organisms that inhabit marine, freshwater, and moist terrestrial ecosystems. The vast number and diversity of microalgal species provide a significant reservoir of biologically active compounds, highly promising for biomedical applications. Diatoms are unicellular eukaryotic algae belonging to the class Bacillariophyceae. They possess intricately structured silica-based cell walls, which contain long-chain polyamines that play important roles in the formation of silica. Long-chain polyamines are uncommon polyamines found only in organisms that produce biosilica. Diatomite, which is a marine sediment of the remains of the silica skeleton of diatoms, could be an abundant source of biogenic silica that can easily be converted to silica particles. This concise review focuses on the biofabrication of polyamine-based nanosilica from diatoms and highlights the possibility of utilizing diatom biosilica as a nanocarrier for drug and siRNA delivery, bioimaging, and bone tissue engineering. The challenges that may affect diatom production, including environmental stresses and climate change, are discussed together with the prospect of increasing diatom-based biosilica production with the desired nanostructures via genetic manipulation. Full article

Integrating algae (microalgae and seaweeds) into monogastric animal diets presents significant opportunities to improve meat quality, safety, and sustainability. This review synthesizes current knowledge on the nutritional and bioactive compounds found in key microalgae (e.g., Chlorella vulgaris, Spirulina, and Nannochloropsis) and seaweeds (e.g., Ascophyllum nodosum, Ulva), emphasizing their potential benefits for animal health and meat production. Algae-enriched diets substantially increase meat omega-3 fatty acid content and antioxidant capacity, thereby enhancing nutritional value, sensory appeal, and shelf life by mitigating lipid and protein oxidation during storage. Additionally, bioactive compounds in algae demonstrate potent antimicrobial activities capable of reducing pathogenic bacteria such as Salmonella, Escherichia coli, and Campylobacter, significantly contributing to improved meat safety. Environmentally, algae cultivation reduces dependency on arable land and freshwater, promotes nutrient recycling through wastewater use, and substantially decreases greenhouse gas emissions compared to traditional livestock feeds. Nevertheless, challenges persist, including high production costs, scalability concerns, variability in nutrient composition, potential contamination with heavy metals and other toxins, and regulatory constraints. Overcoming these limitations through advancements in cultivation technologies, optimized inclusion strategies, and comprehensive market and regulatory analyses is essential to fully realize the potential of algae in sustainable monogastric livestock feeding systems. Full article

Microalgae form the basis of marine food webs, essential in sustaining top predators including seabirds. However, certain species of microalgae synthesize biotoxins, which can accumulate in shellfish and fish and may cause harm to marine animals feeding on them. Toxins produced by dinoflagellates have been previously observed to be poisonous to seabirds. Also, in freshwater and brackish habitats, cyanobacteria have caused bird mortality events. In this work, we analyze the prevalence of six families of biotoxins (paralytic shellfish toxins (PSTs), microcystins (MCs), anatoxins, amnesic shellfish toxins (ASTs), cylindrospermopsin, and tetrodotoxins (TTXs)) in 340 samples from 193 wild birds admitted to a wildlife rehabilitation centre in south Portugal. Furthermore, we consider the clinical picture and signs of 17 birds that presented quantifiable levels of biotoxins in their tissues. The relationship between toxin burdens and the symptomatology observed, as well as possible biotoxin sources, are discussed. Based on previously published research data, we conclude that, in these birds, the biotoxins are unlikely to be the only cause of death but might contribute to some extent to a reduction in birds’ fitness. Full article

Microalgal biotechnology is gaining attention due to its potential to produce pigments, lipids, biofuels, and value-added products. However, challenges persist in terms of the economic viability of microalgal lipid production in photobioreactors due to slow growth rates, expensive media, complex downstream processing, limited product yields, and contamination risks. Recent studies suggest that co-cultivating microalgae with bacteria can enhance the profitability of microalgal bioprocesses. Immobilizing bacteria offers advantages such as protection against shear forces, the prevention of overgrowth, and continuous product secretion. Previous work has shown that biopolymeric immobilization of Paenibacillus polymyxa enhances 2,3-butanediol production. In this study, a novel co-fermentation process was developed by exploiting the chemical crosstalk between a freshwater microalga Scenedesmus obliquus, also known as Tetradesmus obliquus, and an immobilized plant-growth-promoting bacterium, Paenibacillus polymyxa. This co-cultivation resulted in increased metabolite production, with a 1.5-fold increase in the bacterial 2,3-butanediol concentration and a 3-fold increase in the microalgal growth rates compared to these values in free-cell co-cultivation. Moreover, the co-culture with the immobilized bacterium exhibited a 5-fold increase in the photosynthetic pigments and a 3-fold increase in the microalgal lipid concentration compared to these values in free-cell co-cultivation. A fixed bed photobioreactor was further constructed, and the co-cultivation bioprocess was implemented to improve the bacterial 2,3-butanediol and microalgal lipid production. In conclusion, this study provides conclusive evidence for the potential of co-cultivation and biopolymeric immobilization techniques to enhance 2,3-butanediol and lipid production. Full article

Nanoplastics (NPs), an emerging pollutant distributed in different sizes in the aquatic environment, adversely affect aquatic ecosystems. However, knowledge of the effects of NPs of various sizes on phytoplankton, especially freshwater microalgae, is still limited. In this study, we explore the effects of three polystyrene NPs (PS-NPs) with different particle sizes (20, 50, and 80 nm) on the chronic toxicity of a widely distributed freshwater microalga, Chlorella pyrenoidosa. The results showed that PS-NPs-20, PS-NPs-50, and PS-NPs-80 promoted the growth of C. pyrenoidosa at the early stage of exposure, with the highest promotion rates of 46.1%, 56%, and 86.2%, respectively. PS-NPs-20 and PS-NPs-50 inhibited the photosynthesis and growth of C. pyrenoidosa during the mid- and late-exposure periods and also induced an increase in the secretion of reactive oxygen species and extracellular polymers. The highest inhibition rates were 33.2% and 13.6%, respectively. By contrast, the growth-promoting effect of PS-NPs-80 continued until the middle stage, and it was only at the late stage of exposure that some growth-inhibitory effects occurred, with the highest inhibition rate of only 7.8%. The results of transmission electron microscopy showed that PS-NPs-20 damaged algal cells more severely than PS-NPs-50 and PS-NPs-80 on day 21. Notably, a size-dependent effect of PS-NPs was observed on the toxicity of C. pyrenoidosa, but no dose-dependent effect was found. These results will improve our understanding of the toxicity of PS-NPs to microalgae and may provide a basis for evaluating the ecological risk of PS-NPs in freshwater environments. Full article

During our research on the diversity of diatoms and green microalgae from Egypt, four new-to-science, newly recorded, and poorly known species were retrieved from different Egyptian habitats. The new benthic diatom species Halamphora shaabanii A.A. Saber, El-Sheekh, Levkov, H. Saber et Cantonati sp. nov., which could not be identified using the currently available literature, was described from the high-conductivity, oasis lake Abu Nuss in the El-Farafra Oasis, located in the Western Desert of Egypt, employing both light (LM) and scanning electron (SEM) microscopy observations. A detailed comparison of the biometrically distinctive traits, and ecological preferences, of this new diatom species revealed sufficient differentiations from its morphologically most closely related species: H. atacamana, H. caribaea, H. ectorii, H. gasseae, H. halophila, H. mosensis, H. poianensis, and H. vantushpaensis. Ecologically, Halamphora shaabanii can tolerate relatively high nutrients (N and P) and prefers saline inland environments with NaCl water types. The araphid diatom Pseudostaurosiropsis geocollegarum was observed in the epilithic diatom assemblages of the River Nile Damietta Branch and identified on the basis of LM and SEM. From an ecological standpoint, P. geocollegarum seems to prefer elevated nutrient concentrations (meso-eutraphentic species), reflecting different human influences on the freshwater River Nile Damietta Branch. Based on the available literature, this is the first documentation of this freshwater diatom species for Egypt, and the second record for the African continent. Two green motile microalgae, Chlamydomonas proboscigera and Gonium pectorale, were isolated and identified from the terrestrial biomes of the arid habitat “Wadi El-Atshan” in the Eastern Desert of Egypt. C. proboscigera is reported herein for the first time in the Egyptian algal flora, while G. pectorale is poorly documented in the available literature. In light of our findings, the Egyptian habitats, particularly the isolated desert ecosystems, are interesting biodiversity hotspots and have a richer algal microflora than earlier anticipated. Furthermore, more in-depth taxonomic studies, using a combined polyphasic approach, are needed not only to foster our knowledge of the Egyptian and African algal and cyanobacterial diversity and biogeography, but also to be further used in applied environmental sciences. Full article

Sustainability is becoming increasingly important in the world we live in, because of the rapid global population growth and climate change (drought, extreme temperature fluctuations). People in developing countries need more sustainable protein sources instead of the traditional, less sustainable meat, fish, egg, and dairy products. Alternative sources (plant-based, such as grains (wheat, rice sorghum), seeds (chia, hemp), nuts (almond, walnut), pulses (beans, lentil, pea, lupins), and leaves (duckweed), as well as mycoproteins, microalgae, and insects) can compensate for the increased demand for animal protein. In this context, our attention has been specifically focused on duckweed—which is the third most important aquatic plant after the microalgae Chlorella and Spirulina—to explore its potential for use in a variety of areas, particularly in the food industry. Duckweed has special properties: It is one of the fastest-growing plants in the world (in freshwater), multiplying its mass in two days, so it can cover a water surface quickly even in filtered sunlight (doubling its biomass in 96 hours). During this time, it converts a lot of carbon dioxide into oxygen. It is sustainable, environmentally friendly (without any pesticides), and fast growing; can be grown in indoor vertical farms and aquaculture, so it does not require land; is easy to harvest; and has a good specific protein yield. Duckweed belongs to the family Araceae, subfamily Lemnoideae, and has five genera (Lemna, Spirodela, Wolffia, Wolffiella, Landolita) containing a total of approximately 36–38 recognised species. Duckweed is gaining attention in nutrition and food sciences due to its potential as a sustainable source of protein, vitamins, minerals, and other bioactive compounds. However, there are several gaps in research specifically focused on nutrition and the bioaccessibility of its components. While some studies have analysed the variability in the nutritional composition of different duckweed species, there is a need for comprehensive research on the variability in nutrient contents across species, growth conditions, harvesting times, and geographic locations. There has been limited research on the digestibility, bioaccessibility (the proportion of nutrients that are released from the food matrix during digestion), and bioavailability (the proportion that is absorbed and utilised by the body) of nutrients in duckweed. Furthermore, more studies are needed to understand how food processing (milling, fermentation, cooking, etc.), preparation methods, and digestive physiology affect the nutritional value and bioavailability of the essential bioactive components in duckweed and in food matrices supplemented with duckweed. This could help to optimise the use of duckweed in human diets (e.g., hamburgers or pastas supplemented with duckweed) or animal feed. More research is needed on how to effectively incorporate duckweed into diverse cuisines and dietary patterns. Studies focusing on recipe development, consumer acceptance, palatability, and odour are critical. Addressing these gaps could provide valuable insights into the nutritional potential of duckweed and support its promotion as a sustainable food source, thereby contributing to food security and improved nutrition. In summary, this article covers the general knowledge of duckweed, its important nutritional values, factors that may affect their biological value, and risk factors for the human diet, while looking for technological solutions (covering traditional and novel technologies) that can be used to increase the release of the useful, health-promoting components of duckweed and, thus, their bioavailability. This article, identifying gaps in recent research, could serve as a helpful basis for related research in the future. Duckweed species with good properties could be selected by these research studies and then included in the human diet after they have been tested for food safety. Full article