Search Results (529)

Global wastewater generated in unprecedented volumes places a significant strain on aquatic environments, challenging the municipal sector to transition from energy-heavy pollutant removal technologies towards alternative resource recovery strategies with a low carbon footprint. The aim of this work is to review microalgae-based phycoremediation as a sustainable, cost-effective alternative that extracts nutrients from municipal, agricultural, and industrial streams without generating secondary chemical pollution. By utilizing these nutrient-rich effluents, microalgal cultivation generates valuable biomass for downstream valorization into biofuels, biofertilizers, biostimulants, and high-value biopolymers, while eliminating or reducing the costs of synthetic cultivation mediums. However, integrated techno-economic analyses (TEA) and life cycle assessments (LCA) reveal critical socio-technical bottlenecks. Full article

Marine by-products, including fishery discards, seafood-processing residues, aquaculture wastes, crustacean shells, and seaweed-derived side streams, are heterogeneous feedstocks rich in proteins, lipids, minerals, chitinous materials, polysaccharides, and bioactive compounds. This review examines insect-mediated bioconversion as a controlled biorefinery strategy for transforming these unstable marine residues into functional aquafeed ingredients and value-added bioproducts. We compare major marine feedstock classes and industrially relevant insects, with emphasis on substrate–insect matching, moisture control, salinity, lipid and ash load, texture, spoilage risk, and safety. Particular attention is given to how marine substrates can tailor insect meal, insect oil, chitinous fractions, hydrolysates, frass, and functional feed additives. The review further summarizes aquafeed applications of insect-derived products, including fishmeal and fish-oil replacement, protein and amino acid quality, lipid enrichment, gut health, immunity, and disease resistance in aquatic animals. Microbiome-assisted strategies, such as fermentation, enzymatic pretreatment, and gut or substrate microbial management, are discussed as tools to improve substrate stability, digestibility, and product quality. Finally, safety, regulation, scale-up, life cycle assessment, and techno-economic issues are considered. Overall, marine insect biorefineries should be optimized not only for biomass yield, but also for product quality, traceability, and application-specific safety. Full article

Due to Ludwigia octovalvis’ aquatic habitat’s vulnerability to climate change, this study developed an in vitro regeneration system using indirect organogenesis to ensure sustainable production of biomass and secondary metabolites. Treatment T16 (0.1 mg/L BAP and 1.0 mg/L NAA) was identified as the optimal hormonal regimen for callus induction and shoot differentiation. Phytochemical analysis by GC-MS revealed that seedlings regenerated under treatment T16 exhibited a diverse profile of 18 phytoconstituents, enhancing the accumulation of phytosterols, terpenes, and tocopherols. In vitro biological evaluation demonstrated that T16 extract possesses significant antibacterial activity (MIC < 62.5 µg/mL) against methicillin-resistant Staphylococcus aureus, and moderate antioxidant capacity. T16 extract showed anti-inflammatory effects superior to indomethacin at a low quantity (0.5 mg/ear) in adult CD1 mice of both sexes. In conclusion, the indirect organogenesis of L. octovalvis not only conserves the species but also optimizes its pharmacological potential, consolidating it as an efficient biotechnological platform for the development of advanced phytopharmaceuticals. Full article

The water bodies of southern Kazakhstan are under strong anthropogenic pressure, underscoring the relevance of their comprehensive research. In the summer of 2025, hydrobiological and hydrochemical studies were conducted at 32 stations across seven water bodies in the region. The dissolved solids content (TDS) ranged from 239.5 to 1472.5 mg/dm³, with favorable oxygen levels and relatively low nutrient levels. Zooplankton comprised 100 species, with rotifers predominating. Zooplankton abundance was 133.2–1289.9 thousand specimens/m³, with a biomass of 0.99–3.94 g/m³. The average number of species per sample varied from 11.5 to 26.7. The Shannon index values ranged from 1.20 to 2.74 bits. The average individual mass of a specimen varied from 0.0011 to 0.0371 mg. Cluster analysis revealed significant differences in the species composition of planktonic invertebrates across water bodies and their biotopes, which, according to the MDS analysis, reflected heterogeneity in external conditions. Analysis of multivariate data showed that the main factors shaping summer zooplankton community structure in the surveyed water bodies were TDS, silicon, and phosphate. The reasons for the identified dependencies between abiotic and biological variables are discussed. The high indicator significance of zooplankton communities in assessing the ecological state of aquatic ecosystems is demonstrated. Full article

Aquatic ecosystems are under severe stress from a diverse combination of contaminants, including heavy metals, pesticides, pharmaceuticals, and microplastics, driven by rapid industrialization, intensive agriculture, and urbanization. Globally, 80% of wastewater remains untreated, and conventional systems often fail to address emerging contaminants. Consequently, toxic heavy metals like lead and mercury can persist in water sources for decades. In response, phytoremediation has emerged as a scalable, eco-friendly, nature-based alternative. Among phytoremediation agents, duckweeds are increasingly recognized for their rapid growth, simple morphology, and continuous water-column contact. This review outlines the landscape of duckweed-based remediation, detailing molecular detoxification pathways and the synergistic role of associated microbiomes in enhancing environmental cleanup. Evidence indicates that contaminant removal is often supported by plant-microbe interactions. Despite extensive laboratory validation, field-scale implementation remains constrained by environmental complexity, pollutant mixtures, and variable climatic conditions. Furthermore, while duckweed systems hold promise within circular bioeconomy frameworks, converting wastewater into nutrient-rich biomass, contaminant accumulation in plant tissues raises concerns about biomass utilization and contaminant carryover. Addressing these challenges requires an integrative approach that links molecular detoxification, ecological interactions, and engineered system design to realize the full potential of duckweeds for sustainable aquatic pollution management. Full article

Phytoremediation is a sustainable approach for the remediation of heavy metal–contaminated soils; however, the management of contaminated biomass generated during this process remains an insufficiently addressed challenge. Such biomass constitutes a secondary waste stream that may release mobile pollutants and pose environmental risks. In this study, an integrated ecotoxicological assessment framework was applied to evaluate phytoremediation-derived biomass and its transformation products obtained via pyrolysis. Two types of woody biomass with different heavy metal contents and their corresponding biochars produced at 700 °C were investigated. A multitrophic battery of bioassays combining direct exposure assays using terrestrial organisms (higher plants, Eisenia fetida, and soil microbial activity) with leachate-based assays using aquatic organisms (Lemna minor, Daphnia magna, and Aliivibrio fischeri) was applied. Untreated biomass exhibited high to extreme toxicity in aquatic systems (toxic units, TU >100) and significant phytotoxic effects. Pyrolysis substantially reduced contaminant mobility and ecotoxicity of leachates, resulting in lower toxicity (TU typically <15) and no significant effects on plant growth, earthworm survival, or soil microbial functional diversity. Residual toxicity was linked to elevated pH and trace amounts of thermally generated organic substances. These results demonstrate that pyrolysis effectively reduces the environmental risk of contaminated biomass and supports the use of multitrophic ecotoxicological testing for safe waste valorization within circular economy strategies. Full article

Heavy metals such as copper and zinc serve as essential trace elements for photosynthetic organisms at appropriate concentrations. However, at elevated levels, these metals (along with non-essential metals like chromium, lead, mercury, and cadmium) exert severe toxic effects on aquatic life. Heavy metal toxicity primarily relates to oxidative damage in living systems through a direct increase in reactive oxygen species (ROS) and reduction in cellular antioxidant capacity. Previous research on algae of different types with different coverings led us to complete the comparative framework. For this purpose and to assess biotechnological potential, we investigated chromium effects on Euglena gracilis, which possesses a unique pellicle covering, to determine whether it could serve as a chromium biosensor or bioremediation agent. Using Raman spectroscopy and absorption microspectrophotometry (MSP), we found that chromium concentrations of up to 500 μM had no effect on Euglena chlorophyll or carotenoid profiles, consistent with the pellicle preventing chromium entry and protecting the photosynthetic apparatus. However, concentrations > 10 μM severely inhibited growth through extracellular interference with essential nutrient utilization (ammonium phosphate and vitamin B₁₂). Growth inhibition was reversible upon transfer to fresh medium, confirming that cellular machinery remained intact. These results suggest that E. gracilis cannot serve as a chromium biosensor (photosynthetic apparatus unaffected) or bioremediation agent (no chromium internalization), but its ability to maintain photosynthetic functionality in chromium-contaminated environments suggests the potential for alternative applications in polluted water biomass production. Full article

Oily wastewater, especially stable oil-in-water (O/W) emulsions, threatens aquatic ecosystems and is difficult to treat using conventional separation technologies. Herein, a hydrophilic and underwater oleophobic chitosan/polyvinyl alcohol (PVA)/cellulose aerogel (CPCG) was fabricated through a facile one-pot dip-coating strategy. Cellulose aerogel (CG) was prepared by low-temperature dissolution, network reinforcement, washing, and freeze-drying, before being coated with a cross-linked CS/PVA layer using glutaraldehyde, followed by NaOH solidification. SEM revealed a honeycomb-like cellulose framework uniformly covered by the CS/PVA coating, which improved the structural integrity of the skeleton. FT-IR and TG analyses supported the successful construction of the coating and the enhanced thermal stability of CPCG. CPCG displayed a high underwater oil contact angle of 153.8°, which remained above 153° after 30 min, indicating robust underwater oil repellency. Wet CPCG retained 99% of its original height after 30 compression–recovery cycles. Owing to the stable hydration layer, interconnected channels, and improved wet-state resilience, CPCG efficiently separated light and heavy oil/water mixtures and various O/W emulsions. The separation efficiencies for different emulsions were above 99%, and CPCG retained about 93% efficiency after ten cyclohexane/water emulsion separation cycles. This work provides a green and scalable route for constructing biomass-based aerogels for oily wastewater treatment. Full article

The excessive proliferation of aquatic macrophytes in Brazilian reservoirs generates large amounts of biomass that must be removed to ensure water use and energy generation. This material is usually treated as waste, but its recycling as a biofertilizer could mitigate disposal problems while improving soil and crop productivity. To test this potential, we conducted a 4 × 3 factorial experiment using four macrophyte species (Salvinia auriculata Aubl., Myriophyllum aquaticum (Vell.) Verdc., Egeria densa Planch. and Pistia stratiotes L.) collected from the Santana Reservoir, applied at three incorporation doses (5, 10 and 20 t ha⁻¹ dry matter) plus a control in pots with Urochloa decumbens seedlings. Soil chemical properties and plant growth attributes were integrated into the relative Soil Quality Score (rSQS) and relative Plant Performance Score (rPPS). Both scores increased with macrophyte incorporation, though responses depended on species and dose. A significant positive relationship was found between rSQS and rPPS (R² = 0.73; $\rho$ = 0.85), indicating that improvements in integrated soil quality were generally associated with better plant performance. While most treatments improved score values, ELDDE at 20 t ha⁻¹ showed a further increase in rSQS but no proportional gain in rPPS, which was numerically lower than at 10 t ha⁻¹ but not statistically different. This pattern indicates that increases in integrated soil quality may not always translate linearly into plant performance. These results support the potential of selected macrophyte materials as organic amendments and highlight the need for biomass characterization, contaminant monitoring and field validation before practical recommendation. Full article

This article proposes a sustainable approach to producing eco-friendly paper from fibers derived from water hyacinth (Eichhornia crassipes), an invasive aquatic species with potential high lignocellulose content. The research evaluated the possibility of using its biomass as a non-wood raw material for papermaking through an industrial-oriented processing framework. About 10 groups of water hyacinth samples were analyzed by separating their components (roots, leaves, and stems) to determine moisture content, dry biomass yield, fiber distribution, and performance in papermaking. Mechanical pulping and mild alkaline treatment with sodium hydroxide were compared to evaluate their effects on fiber behavior and paper quality. The results showed a high moisture content in the biomass, averaging approximately 88%, while the remaining dry matter represented the usable fibrous material fraction. After fiber classification, it was revealed that the long fibers predominated over the short fibers and the fine fibers (waste), favoring the hydrogen bonding and structural anchoring during sheet formation. Mechanical quality analyses were conducted using the Corrugating Medium Test (CMT), Concora Crush Test (CCT), Ring Crush Test (RCT), and Short Compression Test (SCT). Untreated water hyacinth paper demonstrated mechanical properties comparable to those of an industrial reference paper, including consistent compression resistance and corrugating performance. In contrast, the alkaline-treated sample showed greater structural uniformity but lower mechanical strength due to fiber fragmentation and increased fine production. Overall, the findings showed that Eichhornia crassipes represents a viable and sustainable alternative to non-wood fibers for paper production, offering potential environmental benefits by serving as an invasive species and reducing dependence on wood-based raw materials. Full article

Nowadays, approximately 50% of chemical surfactants come from petrochemical sources and pose environmental risks due to poor biodegradability, affecting microbial communities, aquatic organisms, and terrestrial ecosystems. Biosurfactants are eco-friendly alternatives, thanks to their strong surface tension-reducing activity, stability, low toxicity, and biodegradability, but their large-scale production is still limited by high costs and low yields. In this study, rice husk was evaluated as a renewable substrate from the agro-industrial field for lipopeptide production by the endophytic Bacillus subtilis AC7. Medium optimization through Plackett–Burman designs identified nitrogen sources and pH 6.5 as key factors enhancing biosurfactant production. Under optimized conditions, surfactin production increased from 4.2 mg/L in untreated rice husk to 266–276 mg/L with NaNO₃ and NH₄NO₃ supplementation, respectively. Combined laccase–amylolytic pretreatment further improved substrate utilization, enhancing sugar availability and supporting higher biomass and metabolic activity. In bench-scale fermentation, this condition yielded the highest surfactin concentration (237.5 mg/L). LC-MS/MS analysis confirmed surfactin as the main product, with C15 as the dominant homologue, in both shake-flask and bench-scale fermentations. These findings highlight a novel, sustainable process for surfactin production, offering a renewable alternative to synthetic surfactants while addressing both environmental and economic concerns. Full article

Water hyacinth (Eichhornia crassipes) is among the world’s most invasive aquatic macrophytes, yet quantitative models of shoreline preference remain absent for Lake Victoria. This study developed a distance-based quantitative framework for spatial distribution and decay modelling to quantify seasonal nearshore accumulation dynamics in Winam Gulf, Kenya, using Sentinel-2 imagery. A Support Vector Machine classifier with polygon-mean feature extraction achieved 94–96% accuracy, supported by strong spectral separability (Jeffries–Matusita distance > 1.9 in six bands). During peak dry season, water hyacinth covered 405.81 km² (27.1% of gulf area) and occurred significantly closer to shore than open water (mean preference = 687.9 m; 95% CI: 616.6–753.7 m; p < 0.001). Water hyacinth was 3.10 times more likely than open water to occur within 100 m of shoreline, with 48% of biomass concentrated within 2 km. A power-law decay model of odds ratio with shoreline distance provided superior fit (R² = 0.870, F = 10.06, p = 0.047) compared to exponential decay (R² = 0.477, p = 0.378). Critically, pronounced nearshore preference occurred only during dry-season conditions (+687.9 m to +1946.6 m), while wet–dry transition periods showed no significant preference (−124.2 m; p = 1.00), supporting wind-driven Stokes drift as the dominant transport mechanism and enabling seasonal prioritization of nearshore management interventions. Full article

Dams are widely distributed in global water bodies and cause severe impacts on aquatic ecosystems. In this study, the Sizao River Basin was selected to explore the effects of dams on the macroinvertebrate community, including functional feeding groups (FFGs). Macroinvertebrate communities and environmental variables were monitored seasonally in April, August, October, and November of 2025. A total of 27 taxa were identified, including 3 phyla, 8 orders, and 15 families. Species richness, abundance, biomass, species diversity, and FFGs diversity in the gate-regulated section were generally lower than those in other river sections. Gatherer–collector dominated FFGs across the Sizao River Basin and accounted for most of the dominant species. An ecosystem assessment based on FFGs suggests that ecosystem attributes of macroinvertebrate communities were fragmented. The longitudinal spatial distribution of FFGs was roughly in line with the predications of the river continuum concept. Redundancy Analysis (RDA) indicated that the permanganate index (COD_Mn) and dissolved oxygen (DO) were major environmental variables affecting macroinvertebrate community structure, and DO and salinity (SAL) were major variables affecting FFGs. The explanatory power of RDA for FFGs was higher than that for macroinvertebrate community structure. These findings provide valuable insights into protecting aquatic ecosystems in gate-regulated water bodies. Full article

Duckweeds are minute, fast-growing monocot aquatic plants that propagate clonally and combine high biomass productivity with a valuable biochemical composition (high-quality proteins, a favorable polyunsaturated fatty acid profile, and starch-rich tissues) and efficient nutrient uptake, making them attractive for feed/food, bioenergy, and wastewater-based phyto-bioremediation. Temperature is a key factor shaping duckweed growth, and selecting clones that perform well within specific thermal ranges can improve cultivation across different applications. Here, we screened 97 clones from the genera Spirodela, Landoltia, and Lemna, including the hybrids Lemna × japonica and Lemna × mediterranea, under warm (WC; 30/25 °C) and relative cool (CC; 20/16 °C) conditions. Relative growth rate (RGR) ranged from 0.150 to 0.338 day⁻¹ under WC and from 0.113 to 0.318 day⁻¹ under CC, revealing strong interspecific and intraspecific variation. While WC generally promoted higher growth than CC, notable exceptions occurred at both interspecific and intraspecific levels. Tests under more extreme regimes (EWC; 35/30 °C; ECC; 16/12 °C) confirmed strong clone-specific responses, with some clones maintaining or improving growth under EWC relative to WC, whereas ECC generally reduced growth relative to CC. Climatic provenance was a weak predictor of performance, showing limited correspondence between RGR and mean annual temperature at the site of origin. Overall, these results highlight the value of within-species phenotyping across relevant temperature regimes to identify high-performing duckweed material for applied use. Full article

The increasing global frequency of harmful cyanobacterial blooms (CyanoHABs), driven by nutrient enrichment and climate change, poses a severe threat to aquatic ecosystems and public health. This study evaluates the effectiveness of novel clay–polymer nanocomposites (CPCs) that combine the charge-neutralizing capabilities of polydiallyldimethylammonium chloride (polyDADMAC) with the high clay mineral density (kaolinite and sepiolite) for rapid removal of toxic cyanobacteria from water. Laboratory experiments were performed using Microcystis aeruginosa, Aphanizomenon ovalisporum, and Chlorella sp., with treatment doses determined by particle charge detector (PCD) measurements to identify the “nominal dose” required for full charge neutralization. Results show that clay–polymer nanocomposites achieve over 95% removal of turbidity and chlorophyll in M. aeruginosa at doses significantly lower (15–20%) than the calculated nominal dose, likely due to specific physical bridging interactions with the cyanobacteria’s external exopolysaccharide fibers. In contrast, A. ovalisporum and Chlorella sp. required doses closer to full charge neutralization for optimal removal. Among the materials tested, kaolinite-based nanocomposites (DKG24) showed slightly superior, more stable performance than sepiolite-based nanocomposites. Notably, application at or above the nominal dose was associated with increased soluble microcystin levels, suggesting that excessive polymer concentrations may compromise cell integrity and lead to toxin leakage. These findings suggest that engineered nanocomposites offer highly efficient, scalable technology for CyanoHAB management, provided that operational doses are carefully optimized to maximize biomass removal while minimizing toxin release. Full article