Effect of UV-C Irradiation on Growth, Photosynthetic Pigments, and Lipid Profile of Chlorella sorokiniana.

Chlorella sorokiniana holds significant industrial relevance owing to its lipid profile. Consequently, the objective of this investigation was to enhance growth, lipid content, and photosynthetic pigment production through the application of UV-C irradiation. The growth parameters of microalgae demonstrated an increase in response to concentration. After 35 days of incubation, cells exposed to UV-C for 8 min produced the most biomass at 2.2 g/l. Additionally, the chlorophyll content demonstrated a comparable pattern, with the highest concentrations of chlorophyll a (4.99 mg/l), chlorophyll b (6.22 mg/l), and total chlorophyll (11.21 mg/l) observed in cells incubated for 35 days and exposed to UV-C for 8 min. The lipid profile, nevertheless, demonstrated minor fluctuations. Specifically, the relative abundance of frequently occurring lipid compounds was found to be greater in cells treated with UV-C compared to the control group, and the most significant increase was obtained in 15-day culture exposed to UV-C for 8 min. However, after 35 days of incubation, this abundance decreased in cells exposed to UV-C for more than 4 min. Additionally, the observation of specific lipid compounds presented solely in cells obtained from algal cultures treated with UV-C was made. Consequently, drawing from the results obtained in the current investigation, it is possible to deduce that UV-C can be utilised to augment the overall development and yield of significant metabolites in microalgae. Furthermore, these microalgae can be converted into single-cell bioreactors to facilitate the production of lipids utilised in a variety of applications, a process that could be refined to cater to industrial demands.

CIDACC: Chlorella vulgaris image dataset for automated cell counting.

This CIDACC dataset was created to determine the cell population of Chlorella vulgaris microalga during cultivation. Chlorella vulgaris has diverse applications, including use as food supplement, biofuel production, and pollutant removal. High resolution images were collected using a microscope and annotated, focusing on computer vision and machine learning models creation for automatic Chlorella cell detection, counting, size and geometry estimation. The dataset comprises 628 images, organized into hierarchical folders for easy access. Detailed segmentation masks and bounding boxes were generated using external tools enhancing the dataset's utility. The dataset's efficacy was demonstrated through preliminary experiments using deep learning architecture such as object detection and localization algorithms, as well as image segmentation algorithms, achieving high precision and accuracy. This dataset is a valuable tool for advancing computer vision applications in microalgae research and other related fields. The dataset is particularly challenging due to its dynamic nature and the complex correlations it presents across various application domains, including cell analysis in medical research. Its intricacies not only push the boundaries of current computer vision algorithms but also offer significant potential for advancements in diverse fields such as biomedical imaging, environmental monitoring, and biotechnological innovations.

Measured and predicted floc size of cohesive sediment in the presence of microalgae.

In aquatic environments, biological factors significantly influence the flocculation process of cohesive sediments, thereby impacting sediment transport dynamics. Due to its complexity, the mechanism of biological flocculation still remains unknown. Here, we conducted laboratory experiments to investigate how living microalgae (Skeletonema costatum) affects the flocculation of mineral clay under various shear rates and suspended sediment concentrations (SSC) in saline water. The microalgae (Skeletonema costatum) and SSC both have positive influences on the increase in floc size. However, the shear rate (G) shows dual effect. Specifically, there exists a critical shear rate, G*, at which the floc size increases with G when G≤G* and decreases with G when G>G*. More importantly, G*is affected by SSC and exhibits no dependence on microalgae content. The microalgae (Skeletonema costatum) has a dominant effect on both floc shape and floc size of microalgae-mineral flocs compared to shear rate under the present experimental conditions (SSC: 700 mg/L, chlorophyll-a concentration: 0∼13.76 µg/L, shear rate: 10∼90 s-1). Additionally, the elongated-rod flocs are more easily formed in microalgae-mineral clay suspensions, whereas the plate-stacked flocs are more abundant in pure mineral clay suspensions. The promoting effect of microalgae is obvious under low shear rate conditions (G≤40 s-1), while at high shear rate (G>40 s-1), this effect is significantly attenuated, with a reduction by nearly half. Finally, a new bioflocculation model was proposed to predict the equilibrium median floc size for both conditions with and without microalgae. The model was well validated through comparisons with laboratory measurements.

Integrating electrochemical pretreatment with microalgae treatment for nitrogen and phosphorus removal and resource recovery from swine wastewater.

This study integrates electrochemical pretreatment with microalgae (Scenedesmus obliquus) treatment to enhance nitrogen and phosphorus removal and resource recovery from swine wastewater. By optimizing electrochemical and microalgae treatment conditions, the dilution factor and the hydraulic retention time for microalgae treatment were reduced to 5 times and 7 days, respectively. Under the optimized operational conditions, removal efficiencies of total nitrogen and ammonia could reach over 89 %and 96 %,respectively, and the removal efficiency of total phosphorus was over 99 %. The study also found that aluminum was more suitable than iron for anode as it produced fewer residues. Additionally, the electrochemical pretreatment reduced Cu2+ and Zn2+ concentrations, mitigating negative impacts on microalgal growth. The microalgae biomass harvested from developed processes was rich in saturated fatty acids, which was desirable for biodiesel production. This approach addresses the challenges of nutrient removal for swine wastewater treatment with high quality biomass recovery.

Enhanced emulsification properties of microalgae protein through gellan gum conjugation: Mechanistic insights and applications in curcumin encapsulation and delivery.

The emulsification properties of microalgae protein (MP) are poor, especially under acidic and neutral conditions, which may limit the broad applications of MP in food processing. This study aims to explore the effects of gellan gum (GG) on the emulsification properties of MP. Firstly, MP-GG complexes were prepared and their structures characterized. Subsequently, MP-GG complexes stabilized emulsions were prepared and their stability evaluated. Finally, these emulsions were employed for the encapsulation and delivery of curcumin to evaluate their potential as an efficient nutrient delivery medium. Results indicated that MP-GG complexes were formed under various pH conditions, with pH 6 identified as optimal for complexes stability (zeta-potential value was -31 mV). UV-vis and fluorescence spectroscopy demonstrated that GG did not significantly alter the MP's structure but induced slight conformational changes, leading to the burial of some amino acid residues. Zeta potential measurements confirmed that MP-GG complexes were stabilized by strong electrostatic repulsions. The increase of GG content was conducive to providing more negative charge and promoting the dissolution and dispersion of the MP-GG complexes (MP: GG = 1: 1). Emulsions stabilized by MP-GG complexes exhibited smaller droplet sizes and improved stability compared to those stabilized by MP alone, especially at oil phase volume fractions of 60 % and 70 %. Rheological analysis indicated that GG enhanced emulsion stability by increasing viscosity, and higher oil phase volume fractions facilitated better MP-GG complexes adsorption on oil droplets, strengthening network structures of emulsions. During in vitro simulated gastrointestinal digestion, emulsions with a 70 % oil phase exhibited higher curcumin retention rate (31.09 %) and lower curcumin bioaccessibility (13.23 %) compared to those with a 60 % oil phase. This suggests that emulsions with higher oil phase volume fractions may be more suitable for colon-targeted curcumin delivery, with potential applications in promoting colon health. These findings confirm that the complexation of MP and GG was an effective way to improve the emulsification properties of MP. Emulsions stabilized by MP-GG complexes can serve as stable nutritional delivery systems for fat-soluble bioactive compounds.

Neutrophil-Mimetic Upconversion Photosynthetic Nanosystem Derived from Microalgae for Targeted Treatment of Thromboembolic Stroke.

Thromboembolic stroke constitutes the majority of brain strokes, resulting in elevated mortality and morbidity rates, as well as significant societal and economic burdens. Although intravenous thrombolysis serves as the standard clinical treatment, its narrow therapeutic window and the inflammatory response induced by tissue plasminogen activator (tPA) administration limit its efficacy. In the initial stages of stroke, the abrupt cessation of blood flow leads to an energy metabolism disorder, marked by a substantial decrease in adenosine triphosphate (ATP) and nicotinamide adenine dinucleotide phosphate (NADPH) levels, causing irreversible damage to neural cells. In this study, we introduce a neutrophil-mimetic, microalgae-derived upconversion photosynthetic nanosystem designed for targeted treatment of thromboembolic stroke. This system features upconversion nanoparticles coated with a thylakoid membrane and wrapped in an activated neutrophil membrane, further decorated with ROS-responsive thrombolytic tPA on its surface. The neutrophil-mimetic design facilitates high targeting specificity and accumulation at the thrombus site after intravenous administration. Upon exposure to elevated levels of reactive oxygen species (ROS) at the thrombus location, the nanosystem promptly demonstrated potent thrombolytic efficacy through the surface-modified tPA. Furthermore, near-infrared II (NIR-II) laser irradiation activated the generation of ATP and NADPH, which inhibited inflammatory cell infiltration, platelet activation, oxidative stress, and neuronal injury. This constructed nanoplatform not only showcases exceptional targeting efficiency at the stroke site and controllable release of the thrombolytic agent but also facilitates ATP/NADPH-mediated thrombolytic, anti-inflammatory, antioxidative stress, and neuroprotective effects. Additionally, it offers valuable insights into the potential therapeutic applications of microalgae-based derivatives in managing thromboembolic stroke.

Co-culture systems of microalgae and heterotrophic microorganisms: applications in bioproduction and wastewater treatment and elucidation of mutualistic interactions.

In recent years, reducing the concentration of carbon dioxide in the atmosphere has become an important issue. Microalgae have a higher photosynthetic efficiency and growth rate than higher plants; thus, biological carbon dioxide fixation using microalgae is attracting particular attention as an efficient carbon dioxide fixation method. However, under dilute atmospheric conditions, microalgae exhibit lower growth rates and reduced carbon dioxide fixation efficiency. In recent years, technology that can efficiently fix carbon dioxide, even in the atmosphere, using a microalgae co-culture system that co-cultivates microalgae and heterotrophic microorganisms has attracted attention. In such a co-culture system, it is believed that a mutualistic relationship is established between microorganisms through the exchange of various compounds. This review focuses on the application of a co-culture system of microalgae and heterotrophic microorganisms for bioproduction and wastewater treatment. In addition, research to elucidate the mutualistic relationships in microalgal co-culture systems using analytical methods that have been widely used in recent years, such as next-generation sequencing technology, is also discussed. In the future, it is expected that the use of microalgae co-culture systems will expand on an industrial scale through the development of key technologies, such as efficient genetic modification techniques for microalgae and their heterotrophic microorganism partners, large-scale cultivation facilities that can efficiently cultivate microalgae, and stable control techniques for co-culture systems using advanced technology.

DNA-metabarcoding of cyanobacteria and microalgae in chernozem soils of temperate continental climate of the forest-steppe zone of Eurasia under different degrees of agrotechnology intensification.

Chernozem soil is a valuable resource and contains a great diversity of microorganisms that play a global role in the process of soil formation, the species diversity of which has changed over the last five years under the influence of different agrotechnologies. For the first time, under the conditions of the Central Chernozem region, grain and fallow crop rotation, studies using the DNA-metabarcoding method were carried out to study the taxonomic structure of bacteria, fungi, cyanobacteria, and microalgae communities in the arable horizon of typical medium loamy chernozem under winter wheat cultivation. A comparative analysis of the composition of the genotypes showed significant differences in the presented level of mineral nutrition of the soil NPK (60) and NPK (100) compared with the control variant. After processing the 16S and 18S rRNA datasets, a similar trend of decreasing numbers of pro- and eukaryotic species was found from 6296 (control without MF) to 5310 with NPK (60) and to 4643 with NPK (100), respectively. The Chao1 index indicated that the expected diversity within the prokaryotic group was higher in the control without MF at 211, but decreased to 182 and 193 with NPK (60) and NPK (100) fertilizers, respectively. Analysis of the eukaryotic group revealed a 2.6- and 2.9-fold decrease in diversity by class and genus, respectively, depending on the nutritional levels in agrotechnologies, owing to the use of MF. In the prokaryotic community, Alphaproteobacteria microorganisms predominated at an amount of 14.20-14.46%, with Cyanophyceae accounting for 5.2-9.9%. The diversity of eukaryotes was smaller than the number of classes of prokaryotes; the main dominant were Zygnematophyceae 19.5-41%, Chlorophyceae occupied 10.4-15.8%. On the other hand, the doses of fertilizers used contributed to the emergence of dominant species adapted to high doses of mineral nutrients for plants.

Harmful Microalgae Exhibit Broad Environmental Adaptability in High-Salinity Area Across the Dafengjiang River Estuary.

Harmful algal blooms (HABs) often occur in estuaries due to their unique environmental heterogeneity, posing significant environmental and human health risks. However, there is limited understanding of the community composition and community-level change points (thresholds) of harmful microalgae in subtropical estuaries. This study explored harmful microalgae community structure and thresholds in the Dafengjiang River estuary using a metabarcoding approach. The results revealed 63 harmful microalgae species, and major species included Guinardia flaccida, Prorocentrum cordatum, Thalassiosira punctigera, Pseudo-nitzschia galaxiae and T. gravida. Nonparametric change-point analysis and threshold indicator taxa analysis (TITAN) showed threshold responses of harmful microalgae community structure to ammonium (57.5-60 µg·L-1), total phosphorus (27.8-28.5 µg·L-1) and dissolved inorganic phosphorus (14.5-28 µg·L-1) along the salinity gradient. Wider environmental thresholds were also found in hypersaline areas. Additionally, Pyrodinium bahamense, Pfiesteria piscicida, Skeletonema tropicum and T. punctigera were sensitive to environmental changes and thus could be used as bioindicators. Overall, our study unveiled diverse abrupt transitions of harmful microalgal communities, providing a risk assessment for human health and ecological safety in subtropical estuary ecosystems.

Adaptation of Chlorella vulgaris immobilization on rice straw with liquid manure to create a sustainable feedstock for biogas production and potential feed applications.

Rice straw (RS) is a widely available agricultural residue with significant potential for biogas production and feed applications; however, its poor digestibility and nutritional value limit its utilization. This study explores an innovative approach to enhance the digestibility and nutritional value of RS by cultivating Chlorella vulgaris through immobilization technology on RS, using liquid manure (LM) as an alternative to the traditional BG11 medium. The results showed an increase in chlorophyll a (Chl a) after 12 days for both the BG11 medium and LM-based treatments, from 0.13 to 0.34 and 0.24 mg Chl a/g product (DM), respectively. Additionally, the immobilized microalgal biomass increased to 284.18 and 170.14 mg algal biomass/g product (DM), respectively. Soaking under microaerobic conditions during cultivation led to the partial degradation of RS. This, combined with the formed microalgal biofilm, contributed to an improved digestibility of the dry matter, reaching 69.1% and 65.9% for the final products based on the BG11 medium and LM mediums, respectively, compared to 52.1% for the raw RS. Furthermore, the crude protein and lipids contents were significantly improved with the potential for applications in feed, reaching 21.4% and 4.1% for the BG11 medium-based product, while they were observed to be 12.8% and 3.0%, respectively, for the LM-based product. Additionally, carbon-to-nitrogen ratio was significantly reduced compared to the raw RS. The higher digestibility and improved nutritional value contributed to increased biogas production, reaching 129.3 and 118.7 mL/g (TS) for the products based on the traditional medium and LM medium, respectively, compared to 86.7 mL/g (TS) for the raw RS. The immobilization mechanism and biofilm development could be attributed to the roughness of the RS and extracellular polymer substances. This study demonstrates that integrating C. vulgaris cultivation on RS with LM as a nutrient source not only enhances the digestibility and nutritional value of RS but also offers a sustainable waste management solution with potential applications in biogas production and animal feed.

Mapping intertidal microphytobenthic biomass with very high-resolution remote sensing imagery in an estuarine system.

Microphytobenthos (MPB) contributes significantly to estuarine primary production, so that quantifying its biomass is crucial for assessing their ecosystem functioning. Conventional sampling methods are labour-intensive, logistically challenging, and cannot provide a comprehensive spatial distribution map of MPB biomass. Satellite imagery has offered a feasible alternative for mapping large areas at various temporal and spatial resolutions. However, no imaging device with a spatial resolution consistent with the few square centimetres sampled in-situ has been used in the field. This makes it challenging to accurately relate field biomass measurements with remotely sensed radiometric observations. In this study, two similar multispectral sensors were mounted on an unmanned aerial vehicle (UAV) at different altitudes, as well as on a custom-built device specifically designed to acquire images at ∼1 m altitude, in order to collect very-high spatial resolution reflectance data of MPB biofilms at the Guadalquivir Estuary (Spain) mudflats. In addition, a hyperspectral spectroradiometer acquiring in-situ field reflectance was used for validation. Simultaneously, MPB samples were collected using a 2 mm depth contact corer method, which were analysed through high-performance liquid chromatography (HPLC) to measure the concentrations of major MPB pigments. To assess the relationship between the MPB pigments and different reflectance-based spectral indices, generalised linear mixed effects models (GLMMs) were used, achieving a significant positive relationship between chlorophylls and all spectral indices tested. These models were used to map microphytobenthic biomass, yielding a mean biomass in the range of 30-50 mg Chl-a m-2 in the Guadalquivir estuary during late winter. This study demonstrates the potential of low-altitude/high spatial resolution radiometric imaging as an efficient, rapid, and non-destructive addition to in-situ measurements of MPB biomass, providing exciting perspectives for the monitoring of estuarine systems on a millimetric scale of variability.

Exploring the versatility of Porphyridium sp.: A comprehensive review of cultivation, bio-product extraction, purification, and characterization techniques.

Interest in red microalgae of the Porphyridium genus has surged due to their richness in phycobiliproteins, polyunsaturated fatty acids, and sulfated polysaccharides. These biomasses and their derivatives find applications across food, feed, nutraceutical, pharmaceutical, and cosmetic industries. A deeper understanding of their properties and extraction methods is essential to optimize downstream processing. This paper comprehensively reviews Porphyridium sp., focusing on cultivation techniques, bioproduct extraction, purification, and characterization. It delves into protein, lipid, and polysaccharide extraction, considering the influence of culture conditions on biomass yield. Various methods like chromatography, electrophoresis, and membrane-based techniques for cell lysis and bioproduct recovery are explored, highlighting their pros and cons. By offering diverse insights, this review aims to inspire innovative research and industry progress in red microalgae biotechnology, contributing to sustainable solutions across sectors.

Navigating the microalgal maze: a comprehensive review of recent advances and future perspectives in biological networks.

MAIN CONCLUSION: PPI analysis deepens our knowledge in critical processes like carbon fixation and nutrient sensing. Moreover, signaling networks, including pathways like MAPK/ERK and TOR, provide valuable information in how microalgae respond to environmental changes and stress. Additionally, species-species interaction networks for microalgae provide a comprehensive understanding of how different species interact within their environments. This review examines recent advancements in the study of biological networks within microalgae, with a focus on the intricate interactions that define these organisms. It emphasizes how network biology, an interdisciplinary field, offers valuable insights into microalgae functions through various methodologies. Crucial approaches, such as protein-protein interaction (PPI) mapping utilizing yeast two-hybrid screening and mass spectrometry, are essential for comprehending cellular processes and optimizing functions, such as photosynthesis and fatty acid biosynthesis. The application of advanced computational methods and information mining has significantly improved PPI analysis, revealing networks involved in critical processes like carbon fixation and nutrient sensing. The review also encompasses transcriptional networks, which play a role in gene regulation and stress responses, as well as metabolic networks represented by genome-scale metabolic models (GEMs), which aid in strain optimization and the prediction of metabolic outcomes. Furthermore, signaling networks, including pathways like MAPK/ERK and TOR, are crucial for understanding how microalgae respond to environmental changes and stress. Additionally, species-species interaction networks for microalgae provide a comprehensive understanding of how different species interact within their environments. The integration of these network biology approaches has deepened our understanding of microalgal interactions, paving the way for more efficient cultivation and new industrial applications.

Bioactive Lipids in Dunaliella salina: Implications for Functional Foods and Health.

Dunaliella salina is a green microalga extensively explored for ß-carotene production, while knowledge of its lipid composition is still limited and poorly investigated. Among lipids, polar lipids have been highlighted as bioactive phytochemicals with health-promoting properties. This research aimed to provide an in-depth lipidome profiling of D. salina using liquid and gas chromatography coupled with mass spectrometry. The lipid content was 6.8%, including phospholipids, glycolipids, betaine lipids, sphingolipids, triglycerides, diglycerides, and pigments. Among the total esterified fatty acids, 13.6% were 18:3 omega-3 and 14.7% were 18:1 omega-9. The lipid extract of D. salina showed anti-inflammatory activity by inhibiting cyclooxygenase-2 activity at 100 µg/mL, dose-dependent antioxidant scavenging activity, and antidiabetic activity by inhibiting α-glucosidase activity at 25 and 125 µg/mL. In conclusion, the lipid extract of D. salina has the potential to be used as a functional food ingredient or in the nutraceutical and cosmeceutical industries.

Nannochloropsis oceanica Lipid Extract Moderates UVB-Irradiated Psoriatic Keratinocytes: Impact on Protein Expression and Protein Adducts.

Psoriasis is characterized by excessive exfoliation of the epidermal layer due to enhanced pro-inflammatory signaling and hyperproliferation of keratinocytes, further modulated by UV-based anti-psoriatic treatments. Consequently, this study aimed to evaluate the impact of a lipid extract derived from the microalgae Nannochloropsis oceanica on the proteomic alterations induced by lipid derivatives in non-irradiated and UVB-irradiated keratinocytes from psoriatic skin lesions compared to keratinocytes from healthy individuals. The findings revealed that the microalgae extract diminished the viability of psoriatic keratinocytes without affecting the viability of these cells following UVB exposure. Notably, the microalgae extract led to an increased level of 4-HNE-protein adducts in non-irradiated cells and a reduction in 4-hydroxynonenal (4-HNE)-protein and 15-deoxy-12,14-prostaglandin J2 (15d-PGJ2)-protein adducts in UVB-exposed keratinocytes from psoriasis patients. In healthy skin cells, the extract decreased the UV-induced elevation of 4-HNE-protein and 15d-PGJ2-protein adducts. The antioxidant/anti-inflammatory attributes of the lipid extract from the Nannochloropsis oceanica suggest its potential as a protective agent for keratinocytes in healthy skin against UVB radiation's detrimental effects. Moreover, it could offer therapeutic benefits to skin cells afflicted with psoriatic lesions by mitigating their proliferation and inflammatory responses during UV radiation treatment.

Strain selection and adaptation of a fungal-yeast-microalgae consortium for sustainable bioethanol production and wastewater treatment from livestock wastewater.

This study explores the potential of strain selection and adaptation for developing a fungi-yeast-microalgae consortium capable of integrated bioethanol production and livestock wastewater treatment. We employed a multi-stage approach involving isolation and strain selection/adaptation of these consortiums. The study started with screening some isolated fungi to grow on the cellulosic biomass of the livestock wastewater (saccharification) followed by a fermentation process using yeast for bioethanol production. The results revealed that Penicillium chrysogenum (Cla) and Saccharomyces cerevisiae (Sc) produced a remarkable 99.32 ppm of bioethanol and a concentration of glucose measuring 0.56 mg ml- 1. Following the impact of fungi and yeast, we diluted the livestock wastewater using distilled water and subsequently inoculated Nile River microalgae into the wastewater. The findings demonstrated that Chlorella vulgaris emerged as the dominant species in the microalgal community. Particularly, the growth rate reached its peak at a 5% organic load (0.105385), indicating that this concentration provided the most favorable conditions for the flourishing of microalgae. The results demonstrated the effectiveness of the microalgal treatment in removing the remaining nutrients and organic load, achieving a 92.5% reduction in ammonia, a 94.1% reduction in nitrate, and complete removal of phosphate (100%). The algal treatment also showed remarkable reductions in COD (96.5%) and BOD (96.1%). These findings underscore the potential of fungi, yeast, and Nile River microalgae in the growth and impact on livestock wastewater, with the additional benefit of bioethanol production.

Unveiling significant roles of phytohormone 6-benzylaminopurine in empowering Phaeodactylum tricornutum for high-salinity wastewater treatment and bioresource recovery.

High-salinity presents significant challenges in microalgal wastewater treatment and bioresource recovery due to salinity stress. This study explored the use of salt-tolerant microalgae in conjunction with phytohormone regulation. 1 µM 6-benzylaminopurine increased the biomass of Phaeodactylum tricornutum by 38.3 % and enhanced lipid production by 36.8 %. 6-benzylaminopurine significantly improved the removal of inorganic carbon, total nitrogen, and total phosphorus by 85.2 %, 27.4 %, and 31.9 %. Specifically, 6-benzylaminopurine improved K+ transportation by 71.0 %, increased the activity of Ca2+ transport ATPase and Ca2+ sensors by 49.0 %-83.0 %, optimized osmotic balance, and alleviated salt-induced damage. The contents of proline and extracellular polymers increased by 34.8 % and 35.5 %. A 38.4 % reduction in reactive oxygen species indicated that high-salinity stress was mitigated. The analysis of Sustainable Development Goals showed a 56.2 % improvement in Affordable and Clean Energy. Overall, these findings further highlighted the promising application of the phytohormone 6-benzylaminopurine in microalgal high-salinity wastewater treatment and lipid production.

Chlorella-enriched hydrogels protect against myocardial damage and reactive oxygen species production in anin vitroischemia/reperfusion model using cardiac spheroids.

Microalgae have emerged as promising photosynthetic microorganisms for biofabricating advanced tissue constructs, with improved oxygenation and reduced reactive oxygen species (ROS) production. However, their use in the engineering of human tissues has been limited due to their intrinsic growth requirements, which are not compatible with human cells. In this study, we first formulated alginate-gelatin (AlgGel) hydrogels with increasing densities ofChlorella vulgaris. Then, we characterised their mechanical properties and pore size. Finally, we evaluated their effects on cardiac spheroid (CS) pathophysiological response under control and ischemia/reperfusion (I/R) conditions. Our results showed that the addition ofChlorelladid not affect AlgGel mechanical properties, while the mean pore size significantly decreased by 35% in the presence of the 107cells ml-1microalgae density. Under normoxic conditions, the addition of 107Chlorellacells ml-1significantly reduced CS viability starting from 14 d in. No changes in pore size nor CS viability were measured for hydrogels containing 105and 106Chlorellacells ml-1. In our I/R model, allChlorella-enriched hydrogels reduced cardiac cell sensitivity to hypoxic conditions with a corresponding reduction in ROS production, as well as protected against I/R-induced reduction in cell viability. Altogether, our results support a promising use ofChlorella-enriched Alg-Gel hydrogels for cardiovascular tissue engineering.

Removal of Nitrogen, Phosphorus, Organic Matter, and Heavy Metals from Pig-Farming Wastewater Using a Microalgae-Bacteria Consortium.

Wastewater generated by the pork industry urgently requires the implementation of low-cost, high-benefit, and efficient treatment systems. Accordingly, a microalgae-bacteria consortia-based treatment system is proposed for the removal of contaminants released, by the pork-producing industry, in swine wastewater. In this study, different inoculum concentrations of the microalgae-bacteria consortium were tested to document variation in the removal of nutrients from the wastewater. At varying concentrations, it was efficient and did not present a significant difference in the removal kinetics. The treatment with the greatest amount of inoculum removed close to 87% of total nitrogen, approximately 70% of orthophosphate, and 77% of chemical oxygen demand. Removals of 84% iron, 44% copper, and 48% manganese were also obtained. These results demonstrate that microalgae-bacteria consortia are an economically viable and environmentally desirable option for the efficient treatment of wastewater from the pork industry.

The Cultivation of Halophilic Microalgae Shapes the Structure of Their Prokaryotic Assemblages.

The influence of microalgae on the formation of associated prokaryotic assemblages in halophilic microbial communities is currently underestimated. The aim of this study was to characterize shifts in prokaryotic assemblages of halophilic microalgae upon their transition to laboratory cultivation. Monoalgal cultures belonging to the classes Chlorodendrophyceae, Bacillariophyceae, Trebouxiophyceae, and Chlorophyceae were isolated from habitats with intermediate salinity, about 100 g/L, nearby Elton Lake (Russia). Significant changes were revealed in the structure of algae-associated prokaryotic assemblages, indicating that microalgae supported sufficiently diverse and even communities of prokaryotes. Despite some similarities in their prokaryotic assemblages, taxon-specific complexes of dominant genera were identified for each microalga species. These complexes were most different among Alphaproteobacteria, likely due to their close association with microalgae. Other taxon-specific bacteria included members of phylum Verrucomicrobiota (Coraliomargarita in assemblages of Navicula sp.) and class Gammaproteobacteria (Salinispirillum in microbiomes of A. gracilis). After numerous washings of algal cells, only alphaproteobacteria Marivibrio remained in all assemblages of T. indica, likely due to a firm attachment to the microalgae cells. Our results may be useful for further efforts to develop technologies applied for industrial cultivation of halophilic microalgae and for developing approaches to obtain new prokaryotes with a microalgae-associated lifestyle.