Search Results (367)

Water toxicity screening requires sensitive tools to rapidly detect environmental pollutants. While complex analytical methods accurately determine known contaminants, fast screening tests utilizing biological processes, such as photosynthesis, are increasingly being developed to evaluate the toxicity of environmental waters. We describe the isolation of the psychrotolerant Coccomyxa sp. LT4 from Scarisoara Ice Cave (Romania), representing the first report of green algae inhabiting this type of environment, and provide a preliminary assessment of its isolated thylakoids as novel biorecognition components for water toxicity screening. Photosynthetic activity and diuron sensitivity were measured amperometrically and compared with thylakoids from the reference cyanobacterium Synechococcus elongatus PCC 7942. The bioreceptor’s response to various pollutants and water salinities was also investigated. The microalgal thylakoids were more sensitive to diuron than the reference thylakoids, generated stable photocurrents across a broad salinity range and, when lyophilized with sucrose, retained their activity for over two years at −20 °C. Consequently, these thylakoids, isolated from a cold-environment microalga, provide a promising basis for developing biosensors for in situ toxicity screening in low-temperature aquatic ecosystems. Full article

Actual printing and dyeing wastewater (APDW), as one of the most difficult types of wastewater to treat, has become a significant environmental risk due to its toxicity and the challenges associated with its degradation. Microalgae-based treatment of APDW is a promising, eco-friendly, and cost-effective strategy. In this study, a cyanobacterium, Synechocystis aquatilis, was isolated from APDW. The strain demonstrated good environmental tolerance and the capacity to remove pollutants and valorize biomass simultaneously. Under optimized conditions, it removed COD (120.27 mg·L⁻¹·d⁻¹), NH₄-N (0.89 mg·L⁻¹·d⁻¹), and total phosphorus (9.52 mg·L⁻¹·d⁻¹), while achieving substantial decolorization. The strain concurrently accumulated lipids (373.08 mg/g), polysaccharides (167.85 mg/g), and proteins (72.05 mg/g). Mechanistic analyses revealed that S. aquatilis microalgae adsorb dyes and impurities via bioadsorption and then biodegrade dyes and nitrogen and phosphorus compounds via NADPH generation, glutamate and butyrate metabolism, and oxidoreductase activity. This study presents a promising application of S. aquatilis as a novel and environmentally friendly treatment method for APDW, enabling simultaneous wastewater treatment and resource recovery. Full article

Aquaculture is the fastest-growing food production sector, supplying more than half of the world’s seafood and projected to expand further to meet rising global protein demands. Among the various pressures confronting this industry, harmful algal blooms (HABs) rank among the most alarming. Ichthyotoxic flagellates are microalgae known for producing toxins or inducing gill damage that leads to widespread fish mortality. Their increasing frequency poses a critical threat to aquaculture, emphasizing the urgent need for effective and environmentally sustainable strategies to regulate and mitigate these harmful episodes. This study investigated the responses of three ichthyotoxic flagellates renowned for impacting aquaculture operations (Prymnesium parvum, Heterosigma akashiwo, and Fibrocapsa japonica) and tested their susceptibility to two routinely applied chemical agents, hydrogen peroxide (H₂O₂) and copper sulfate (CuSO₄). Mortality, viability, and motility were assessed alongside trajectory-based metrics, including mean squared displacement (MSD) and probability density function (PDF). The results revealed species-specific sensitivities: P. parvum was highly susceptible to H₂O₂, while H. akashiwo and F. japonica were more susceptible to copper toxicity. Ichthyotoxic flagellates exhibited differential sensitivities to chemical treatments, with copper sulfate generally achieving lower EC₅₀ thresholds and greater inhibition of motility than hydrogen peroxide, except in P. parvum. The rapid attenuation of motility at sublethal concentrations highlights swimming behavior as a functional vulnerability, reinforcing the potential for behavior-based mitigation strategies that minimize chemical loading and reduce unintended impacts on cultured fish and surrounding ecosystems. 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

Liver regeneration after partial hepatectomy (PH) is critically influenced by redox balance, which may be severely disrupted under drug-induced liver injury. This study evaluated oxidative stress parameters and inflammatory markers in rats subjected to 70% PH following acetaminophen (APAP)-induced toxicity and assessed the preventive effect of the microalga Desmodesmus armatus. Reactive oxygen species (superoxide anion, hydroxyl radical, and hydrogen peroxide), antioxidant enzyme activities (superoxide dismutase and glutathione peroxidase), serum aminotransferases, bilirubin, and C-reactive protein were analyzed 0–168 h post-hepatectomy. APAP intoxication markedly increased mitochondrial ROS production, suppressed mitochondrial antioxidant enzyme activity, and prolonged elevations of ALT, AST, bilirubin, and CRP, accompanied by severe histological damage. Preventive administration of D. armatus suspension (10 mL/kg body weight at 1.5 × 10⁶ and 1.5 × 10⁷ cells/mL) attenuated oxidative stress in a dose-dependent manner. It significantly reduced ROS levels, restored mitochondrial antioxidant defenses, decreased cytolytic and cholestatic markers, and mitigated systemic inflammation. Overall, D. armatus exhibited hepatoprotective and redox-modulating properties, which may contribute to a more favorable microenvironment for liver recovery under toxic conditions. These findings highlight the potential of microalgae-based interventions as supportive strategies for reducing liver injury and improving recovery following acute liver injury. Full article

Understanding the toxicity of micro- and nanoplastics (MNPs) in aquatic systems, combined with temperature, is essential in order to assess ecological hazard in a multi-stressor environment. This study investigated the biological responses of marine and freshwater organisms of different trophic levels (including primary producers, decomposers, and consumers) exposed to polystyrene (PS) MNPs, tested at varying concentrations and particle sizes under two temperature conditions (control and +2 °C). Overall, differences were observed between trophic levels: Paracentrotus lividus larvae were more sensitive to higher temperatures, Daphnia magna exhibited a non-linear pattern, and microalgae have generally shown low sensitivity to both MNPs and high temperatures. However, the MNPs’ responses were not generally concentration-dependent, with the exception of Dunaliella tertiolecta. The effects recorded at increased temperature generally varied among species, indicating that even a moderate increase in temperature can modulate responses in different organisms. In the marine system, hazard levels increased with temperature, whereas in freshwater, they were higher but temperature-independent. These results highlight the importance of integrated assessment approaches to accurately evaluate the ecological hazard associated with MNPs pollution in the context of climate change. Full article

Despite their vital physiological roles, oxidative imbalance caused by reactive oxygen, nitrogen, sulphur, and chlorine species damages essential body macromolecules such as proteins, lipids, and nucleic acids through oxidative stress. This stress is strongly associated with cancer, inflammation, neurological and cardiovascular disorders, and other chronic human diseases. Therefore, antioxidants, natural or synthetic, that counteract oxidative damage are important, with increasing interest in their use within the pharmaceutical, food, and cosmetic industries. However, due to toxicity concerns with the synthetic variants, natural antioxidants are increasingly preferred. Extremophile-derived antioxidants, such as superoxide dismutases, catalases, peroxidases, carotenoids, and melanin, are of renewed interest due to their remarkable stability, robustness, and potency under extreme conditions of temperature, pH, and salinity. These make them better than many mesophile-derived antioxidants and excellent candidates for cost-effective biotechnological, research, and industrial processes that require high operational efficiency. This review summarises key classes of selected enzymatic and pigment antioxidants, their mechanisms of action, and their industrial relevance, with a focus on extremophilic microalgae, bacteria, and fungi. The benefits of extremophilic antioxidants are discussed alongside their current applications and existing challenges, including the need to develop efficient delivery systems, scalability issues, and limited characterisation. Full article

Polysaccharides derived from cyanobacteria and microalgae have attracted increasing interest as natural virucidal agents. Among them, polysaccharides from the cyanobacterium Arthrospira platensis (A. platensis), and the green microalgae Dunaliella salina (D. salina) have shown virucidal activities, mainly against enveloped viruses, while evidence on non-enveloped viruses is still limited. In this study, the virucidal activity of purified polysaccharides extracted from A. platensis (APPs) and from D. salina (DSPs) was evaluated in vitro against human adenovirus type 5 (HAdV5), a non-enveloped pathogenic virus with high persistence in the environment and resistance to disinfection. The in vitro assays were carried out at concentrations previously verified as non-toxic by morphological evaluation of A549 cells after 24 and 48 h of incubation, testing two viral loads, namely, 10³ and 10⁴ tissue culture infectious dose 50% per milliliter (TCID₅₀/mL). For APPs, a possible time-dependent effect was also assessed at different contact times (15, 30 and 60 min). DSPs showed a limited virucidal effect related to the starting viral concentration, while APPs induced a consistent viral reduction (up to 98.8%) at both viral concentrations. The virucidal effect of APPs occurred rapidly and was not significantly influenced by contact time, thus suggesting that prolonged exposure is not a determining factor for polysaccharide virucidal activity. These findings demonstrate the virucidal activity of APPs against a highly resistant non-enveloped virus and provide preliminary in vitro evidence of their potential application as natural virucidal agents, particularly for environmental disinfection purposes. Further investigations are warranted to elucidate the underlying mechanisms of action and to optimize their practical use. Full article

This study assesses the environmental performance of three wastewater treatment setups through an attributional, gate-to-gate life cycle assessment (functional unit: 1 m³ of treated wastewater): (Sc1) a traditional municipal wastewater treatment plant, (Sc2) an aquaculture recirculation system using microalgae, and (Sc3) a domestic system combining UASB pretreatment with microalgae polishing. Inventory data were analyzed in SimaPro with ReCiPe 2016 Midpoint (Hierarchist) across seven effect categories. Robustness was tested through sensitivity analyses (±20%) of power consumption and influent characteristics, as well as an additional scenario exploring the offset of methane-recovery electricity. The global warming impact remained consistent across scenarios, ranging from 60.5 to 65.1 kg CO₂-eq·m⁻³, indicating no significant difference within the operational parameters. In most categories, power consumption and influent-related burdens were the main contributors, while the impacts from flocculants and microalgae inoculum were minimal. Sc3 showed a lower freshwater eutrophication potential compared to Sc1 and Sc2 (0.028 vs. approximately 0.049 kg P-eq·m⁻³). Normalization highlighted human carcinogenic toxicity and aquatic ecotoxicity as key impact categories. The methane-offset scenario caused only slight changes at low CH₄ outputs, suggesting that energy recovery depends on context. Full article

Due to their exceptional nutritional benefits, microalgae and cyanobacteria are recognized as sustainable food sources and key contributors to the circular bioeconomy. Arthrospira sp. has garnered significant attention as one of the most promising cyanobacteria for a wide range of applications. The purpose of this study is to systematically analyze and synthesize global research trends in Arthrospira sp. applications. In this context, a “systematic review” refers to an integrated bibliometric and thematic analysis encompassing publication trends, geographical distribution of research outputs, leading journals, key application sectors, market development, and associated challenges and future prospects. Consequently, extensive research has been conducted on this species, leading to diverse areas of interest and application. This review article is the first of its kind, offering a comprehensive summary of trends in Arthrospira sp. applications over the past 15 years. It presents a bibliometric analysis of publications from 2010 to 2024 in journals indexed by Scopus. The analysis revealed that Bioresource Technology is the leading journal in publishing related research, with China producing the highest number of studies. Furthermore, phycocyanin extraction emerged as the most frequently studied application. Recently explored applications include its use as a biofertilizer, in bioplastic production, and in cosmetics. The Arthrospira sp. market is currently valued at an estimated $619 million in 2024, positioning it as a dominant player in the global industry. However, challenges persist, including safety concerns related to potential allergies and toxicity, as well as regulatory hurdles that may affect commercialization and market expansion. Full article

Electronic waste (e-waste) has emerged as one of the most critical environmental challenges of the twenty-first century. It encompasses a wide range of discarded electrical and electronic equipment, including information and communication technologies, household appliances, entertainment systems, and related components. While e-waste contains valuable recoverable materials, it also harbours hazardous substances such as toxic heavy metals, flame retardants, and persistent organic pollutants. Inadequate disposal practices, particularly open dumping and landfilling, result in the generation of toxic leachates that contaminate soil as well as surface and groundwater, posing severe threats to environmental integrity and public health. Evidence indicates that landfill leachates can infiltrate groundwater at considerable depths, exceeding permissible limits of heavy metals and metalloids and contributing to serious health disorders. Consequently, the implementation of effective e-waste management strategies and environmentally sound disposal practices is imperative to minimize its detrimental environmental and human health impacts. Microalgae systems can achieve up to 98% removal efficiency and up to five cycles reusability. In this paper, the drawbacks of the traditional methods for metal recovery from e-waste and the potential of microalgae were discussed. The downstream processing and metal extraction from microalgal biomass is critically discussed as well as strategies to support the circular economy. Full article

Phytoplankton are key indicators of water quality and low-cost tools for freshwater monitoring, yet their diversity and ecological drivers remain poorly documented in the Tropical Andes. This study provides the first national-scale, multi-ecosystem assessment of net phytoplanktonic communities (including microalgae and cyanobacteria), across Ecuador, integrating physicochemical, multivariate, and geospatial analyses. Eighteen lakes and rivers from three biogeographic regions and a wide altitudinal gradient were surveyed, yielding 129 taxa, 77 identified at species level, the most comprehensive checklist reported to date for Ecuador. Community structure showed a clear lentic–lotic differentiation driven by hydrodynamic contrasts, while the absence of distance–decay patterns indicated high dispersal and environmental filtering pattern rather than spatial structuring. Anthropogenic pressure acted as a secondary gradient: pristine high-Andean lakes were dominated by desmids and diatoms, whereas agricultural and urban basins showed chlorophyte and potentially toxic cyanobacterial assemblages. Palmer’s Index detected organic pollution but underestimated eutrophication in endorheic, geochemically enriched lakes. Land-use effects presented strong basin-scale signals in lakes but weak correlations in rivers due to overriding hydromorphological constraints. These findings establish a robust spatial baseline for freshwater bioassessment in the Andes, demonstrating the value of phytoplankton as effective, low-cost indicators readily applicable to national water-quality assessment programs. Full article

Conventional wastewater treatment methods often rely on energy-intensive physical and chemical processes that are costly and may generate secondary pollution. These limitations have prompted the exploration of more sustainable alternatives. Among them, phycoremediation, particularly using microalgae, has emerged as a promising strategy for mitigating environmental pollution. Microalgae possess unique capabilities to sequester heavy metals, assimilate nutrients, and degrade emerging contaminants while simultaneously producing valuable biomass. The efficacy of microalgal bioremediation can be enhanced through omics-based approaches, which enable these biological agents to convert toxic compounds into non-toxic forms and improve ecosystem health. Additionally, forming microalgae–microorganism consortia can enhance process efficiency and cost-effectiveness. This review highlights multi-pronged strategies for pollutant mitigation in wastewater, focusing on environmentally and economically viable microalgal cultivation systems. It also identifies research gaps and discusses the potential for biomass valorization into economically important products. Full article

Aquatic ecological issues have garnered significant attention in recent years, driving the demand for convenient, effective, and systematic assessment methods in environmental risk evaluation. This review provides a comprehensive introduction to methodologies for assessing the toxicity of chemicals toward aquatic microorganisms, which include viruses, bacteria, fungi, protozoa, and algae. Among these, microalgae are commonly used as model organisms due to their relative simplicity. The article details conventional biological methods, general chemical techniques, modern instrumental analyses, and informatics approaches, with a particular focus on algae and bacteria as model organisms for toxicity assessment. The principles, advantages, and limitations of each method are discussed, along with examples of their application in various contexts. Biological methods offer direct visualization, convenience, and rapid results, while modern instrumental techniques enable mechanistic insights at molecular and biochemical levels. Informatics methods facilitate toxicity evaluation in complex systems. While aquatic microorganisms encompass viruses, fungi, protozoa, bacteria, and algae, this review primarily focuses on bacteria and algae as model organisms due to their ecological relevance, sensitivity, and widespread use in standardized assays. Full article

Background: As a widely used chemotherapeutic agent, cisplatin frequently induces acute kidney injury (AKI), which severely compromises patient survival and limits its clinical use. While the natural flavonoid diosmetin (Dio) shows promise in mitigating cisplatin-induced nephrotoxicity, its clinical translation is challenged by poor solubility, low bioavailability, and incompletely elucidated mechanisms. This study aimed to overcome these limitations by developing a novel drug delivery system using the microalgae Dunaliella salina (D. salina, Ds) to load Dio (Ds-Dio), thereby enhancing its efficacy and exploring its therapeutic potential. Methods: We first characterized the physicochemical properties of Ds and Dio, and then Ds-Dio complex was synthesized via co-incubation. Its nephroprotective efficacy and safety were systematically evaluated in a cisplatin-induced mouse AKI model by assessing renal function (serum creatinine, blood urea nitrogen), injury biomarkers, histopathology, body weight, and organ index. The underlying mechanism was predicted by network pharmacology and subsequently validated experimentally. Results: The novel Ds-Dio delivery system has been successfully established. In the AKI model, Ds-Dio significantly improved renal function and exhibited a superior protective effect over Dio alone; this benefit is attributed to the enhanced bioavailability provided by Ds carrier. In addition, Ds-Dio also demonstrated safety performance, with no evidence of toxicity to major organs. Network pharmacology analysis predicted the involvement of PI3K/AKT pathway, which was experimentally verified. Specifically, we confirmed that Ds-Dio alleviates AKI by modulating the PI3K/AKT pathway, resulting in concurrent suppression of NF-κB-mediated inflammation and activation of NRF2-dependent antioxidant responses. Conclusions: This study successfully developed a microalgae-based drug delivery system, Ds-Dio, which significantly enhances the nephroprotective efficacy of Dio against cisplatin-induced AKI. The nephroprotective mechanism is associated with modulation of the PI3K/AKT pathway, resulting in the simultaneous attenuation of oxidative stress and inflammation. Full article