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Chlorella vulgaris and Tetraselmis chuii are two microalgae species already marketed because of their richness in high-value and health-beneficial compounds. Previous studies have demonstrated the biological properties of compounds isolated from both microalgae, although data are not yet available on the impact that pre-treatment and gastrointestinal digestion could exert on these properties. The aim of the present study was to analyze the impact of the biomass pre-treatment (freeze/thaw cycles plus ultrasounds) and simulated gastrointestinal digestion in the bioaccessibility and in vitro antioxidant activity (ABTS, ORAC, Q-FRAP, Q-DPPH) of the released digests. The cell wall from microalgae were susceptible to the pre-treatment and the action of saliva and gastric enzymes, releasing bioactive peptides and phenolic compounds that contributed to the potent antioxidant activity of digests through their radical scavenging and iron reduction capacities. Our findings suggest the potential of these microalgae against oxidative stress-associated diseases at both, intestinal and systemic level., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Tetraselmis chuii is a microalgae marketed as ingredient meeting the acceptance criteria for novel foods established by the European Union and can be an important source of healthy fatty acids (FA). The aim of this research was to characterize the FA profile of T. chuii fractions obtained by supercritical carbon dioxide (SCCO 2 ) extraction operating with two sequential co-solvents and to evaluate the effect of biomass pretreatment (freeze/thaw cycles followed by ultrasounds). T. chuii biomass was confirmed to be an important source of omega-3 FA, mainly due to the abundance of α-linolenic acid, and pre-treatment significantly improved the lipid yield. Other omega-3 FA, such as 16:3, 16:4, 18:4, 18:5, 20:3 and 20:5, were also detected in different proportions. When SCCO 2 extraction of pretreated and un-pretreated T. chuii was compared with conventional solvent extraction, the nutritional quality indices of the extracts were improved by the use of SCCO 2 ., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

This work proposes a new data-driven model to estimate and predict pH dynamics in freshwater raceway photobioreactors. The resulting model is based purely on data measured from the reactor and divides the pH dynamics into two different behaviors. One behavior is described by the variation of pH due to the photosynthesis phenomena made by microalgae; and the other comes from the effect of CO 2 injections into the medium for control purposes. Moreover, it was observed that the model parameters vary throughout the day depending on the weather conditions and reactor status. Thus, a decision tree algorithm is also developed to capture the parameter variation based on measured variables of the system, such as solar radiation, medium temperature, and medium level. The proposed model has been validated for a data set of more than 100 days during 10 months in a semi-industrial raceway reactor, covering a wide range of weather and system scenarios. Additionally, the proposed model was used to design an adaptive control algorithm which was also experimentally tested and compared with a classical fixed parameter control approach., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Integrated aquaculture wastewater treatment systems (IAWTSs) are widely used in treating aquaculture wastewater with the aeration-microalgae unit serving as an important component. In this study, we artificially constructed an IAWTS and applied two aeration-microalgae methods: ordinary aeration or ozone nanobubbles (ONBs) with microalgae (Nannochloropsis oculata). The impact of N.oculata and ONBs on the removal performance of nutrients and the underlying micro-ecological mechanisms were investigated using 16S rRNA gene amplicon sequencing. The results demonstrated that the combined use of ONBs and N.oculata exhibited superior purification effects with 78.25%, 76.59% and 86.71% removal of COD Mn , TN and TP. N.oculata played a pivotal role as the primary element in wastewater purification, while ONBs influenced nutrient dynamics by affecting both N.oculata and bacterial communities. N.oculata actively shaped bacterial communities, with a specific focus on nitrogen and phosphorus cycling in the micro-environment remodeled by ONBs. Rare bacterial communities displayed heightened activity in response to the changes in N.oculata, ONBs, and nutrient levels. These findings provide a novel approach to improve the technological processes the IAWTS, contributing to the advancement of sustainable aquaculture practices by offering valuable insights into wastewater purification efficiency and micro-ecological mechanisms., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Oxidative stress is a universal interpretation for the toxicity mechanism of nanoplastics to microalgae. However, there is a lack of deeper insight into the regulation mechanism in microalgae response to oxidative stress, thus affecting the prevention and control for nanoplastics hazard. The integrated analysis of transcriptomics and metabolomics was employed to investigate the mechanism for the oxidative stress response of Chlorella pyrenoidosa to nanoplastics and subsequently lock the according core pathways and driver genes induced. Results indicated that the linoleic acid metabolism, glycine (Gly)-serine (Ser)-threonine (Thr) metabolism, and arginine and proline metabolism pathways of C. pyrenoidosa were collectively involved in oxidative stress. The analysis of linoleic acid metabolism suggested that nanoplastics prompted algal cells to secrete more allelochemicals, thereby leading to destroy the immune system of cells. Gly-Ser-Thr metabolism and arginine and proline metabolism pathways were core pathways involved in algal regulation of cell membrane function and antioxidant system. Key genes, such as LOX2.3, SHM1, TRPA1, and proC1, are drivers of regulating the oxidative stress of algae cells. This investigation lays the foundation for future applications of gene editing technology to limit the hazards of nanoplastics on aquatic organism., Competing Interests: Declaration of Competing interest This paper is our unpublished work and it has not been submitted to any other journal for reviews. Thus, it has not been previously published, in whole or in part, and it is not under consideration by any other journal. Additionally, I confirm that both authors are aware of, and accept responsibility for, the manuscript. There is no conflict of interest., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Algal-bacterial granular sludge (ABGS) composed of microalgae and aerobic granular sludge, is a sustainable and promising technology for wastewater treatment. However, the formation mechanism of ABGS has not been clearly defined, and the direct formation of ABGS in saline wastewater has rarely been investigated. This study proposed novel insights into the granulation process of ABGS by assembling the algal barrier, which was successfully cultivated directly in saline wastewater. The results concluded that ABGS with the algal barrier maintained a higher biomass (MLSS of 7046 ± 61 mg/L), larger particle sizes (1.21 ± 0.06 mm), and better settleability (SVI 30 of 46 ± 1 mL/g), enabling efficient pollutants removal. Soluble microbial products (SMP) were found to be closely related to the emergence of the algal barrier. In addition, under salinity stress, the high production of extracellular polymeric substances (EPS, 133.70 ± 1.40 mg/g VSS), specifically TB-EPS (90.29 ± 1.12 mg/g VSS), maintained a crucial role in the formation of ABGS. Further analysis indicated that biofilm producing bacteria Pseudofulvimonas and filamentous eukaryote Streptophyta were the key players in ABGS formation with the algal barrier. Furthermore, the enhancement of key genes and enzymes involved in nitrogen metabolism, TCA cycle, and polysaccharide metabolism suggested a more robust protective effect provided by the algal barrier. This study is expected to advance the application of simultaneous ABGS formation and pollutant removal in wastewater., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Field observations form the basis of the majority of studies on microphytobenthic algal communities in freshwater ecosystems. Controlled mesocosm experiments data are comparatively uncommon. The few experimental mesocosm studies that have been conducted provide valuable insights into how multiple stressors affect the community structures and photosynthesis-related traits of benthic microalgae. The recovery process after the stressors have subsided, however, has received less attention in mesocosm studies. To close this gap, here we present the results of a riparian mesocosm experiment designed to investigate the effects of reduced flow velocity, increased salinity and increased temperature on microphytobenthic communities. We used a full factorial design with a semi-randomised distribution of treatments consisting of two levels of each stressor (2 × 2 × 2 treatments), with eight replicates making a total of 64 circular mesocosms, allowing a nuanced examination of their individual and combined influences. We aimed to elucidate the responses of microalgae communities seeded from stream water to the applied environmental stressors. Our results showed significant effects of reduced flow velocity and increased temperature on microphytobenthic communities. Recovery after stressor treatment led to a convergence in community composition, with priority effects (hypothesized to reflect competition for substrate between resident and newly arriving immigrant taxa) slowing down community shifts and biomass increase. Our study contributes to the growing body of literature on the ecological dynamics of microphytobenthos and emphasises the importance of rigorous experiments to validate hypotheses. These results encourage further investigation into the nuanced interactions between microphytobenthos and their environment and shed light on the complexity of ecological responses in benthic systems., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Arthrospira (Limnospira) maxima (A. maxima) and Chlorella vulgaris (Ch. vulgaris) are among the approved microalgae and cyanobacteria (MaC) in the food industry that are known to be safe for consumption. However, both organisms are controversial regarding their vitamin B 12 content, due to the possible occurrence of pseudo-cobalamin. Concurrently, their nutrition profiles remain understudied. The main purpose of the present study was to identify their nutrition profiles, focusing mainly on vitamin B 12 , amino acids, and micronutrients under iron-induced hormesis (10 mg/L Fe in treated samples). Our findings indicate a higher B 12 content in A. maxima compared to Ch. vulgaris (both control and treated samples). Using liquid chromatography with tandem mass spectrometry (LC-MS/MS), the cyanocobalamin content was determined as 0.42 ± 0.09 μg/g dried weight (DW) in the A. maxima control and 0.55 ± 0.02 μg/g DW in treated A. maxima, resulting in an insignificant difference. In addition, the iron-enriched medium increased the amount of iron in both tested biomasses (p < 0.01). However, a more pronounced (approximately 100×) boost was observed in Ch. vulgaris, indicating a better absorption capacity (control Ch. vulgaris 0.16 ± 0.01 mg/g Fe, treated Ch. vulgaris 15.40 ± 0.34 mg/g Fe). Additionally, Ch. vulgaris also showed a higher micronutrient content. Using both tested microalgae, meeting the sufficient recommended daily mineral allowance for an adult is possible. By combining biomass from A. maxima and Ch. vulgaris in a ratio of 6:1, we can fulfill the recommended daily allowance of vitamin B 12 and iron by consuming 6 tablets/6 g. Importantly, iron hormesis stimulated amino acid composition in both organisms. The profile of amino acids may suggest these biomasses as promising potential nutrition sources., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

The utilization of heterologous 5' untranslated regions (5'UTRs) for expressing foreign proteins in the chloroplast of Chlamydomonas reinhardtii (C. reinhardtii) has posed a persistent challenge over the years. This challenge stems from the lack of a defined and comprehensive set of translational cis-elements responsible for stability, ribosome binding, and translation initiation, which are mediated by trans-acting factors native to C. reinhardtii. In the current study, we aimed to address this bottleneck by employing the 5'UTR from gene 10 of the T7 bacteriophage (T7g10 5'UTR), fused to the promoter of C. reinhardtii small subunit ribosomal RNA (rrnS), to facilitate the translation of a reporter gene, YFP. Using a chimeric construct, the YFP mRNA was efficiently translated utilizing the heterologous T7g10 5'UTR. Furthermore, the accumulation of YFP protein under the control of the T7g10 5'UTR was approximately one third of that observed under the control of the endogenous psaA promoter/5'UTR in the C. reinhardtii chloroplast. The results of computational analyses demonstrated that the T7g10 5'UTR sequence shares common elements with the endogenous 5'UTRs of the chloroplast genes. Moreover, the findings of the current study highlighted the potential of employing bacteriophage 5'UTRs for the foreign protein accumulation from the chloroplast genome of C. reinhardtii., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

The membrane fouling induced by algal extracellular organic matter (EOM) remain a bottleneck in restricting ultrafiltration (UF) application during harmful algal-water treatment. In current study, the application of heat-activated peroxydisulfate (PMS) and coagulation (Aluminum chlorohydrate, PACI) on membrane fouling behavior during Chlorella-laden water treatment was investigated. The membrane fouling mechanism was analyzed using the extended Derjaguin-Landau-Verwey-Over-beek (XDLVO) theory. The results revealed that separated heat-activated PMS could enhance the filtration flux of EOM at high PMS does > 0.2 mM, whereas the membrane fouling was further alleviated by combined heat-activated PMS (0.2 - 1.0 mM) and PACI (20 mg/L) treatment, especially at low PMS dose. Combined heat-activated PMS and PACI pretreatment could effectively increase the adhesive repulsion between membrane and foulants and reduce the cohesion free energies between organic foulants than those by separated heat-activated PMS treatment, making the initial filtration flux reduced and the cake layer looser. Moreover, the organic foulants of proteins, polysaccharides, and humic-like organics were removed. Cake formation was the major fouling mechanism when EOM was treated with/without separated heat-activated PMS treatment, whereas the membrane fouling mechanism was changed from cake layer formation to pore blocking after combined heat-activated PMS and PACI treatment. Overall, this research provided a feasible method in membrane fouling control during Chlorella -laden water treatment., Competing Interests: Declaration of Competing Interest ☒ The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. ☐ The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:, (Copyright © 2024. Published by Elsevier Inc.)

Reduced-fat labneh, while offering health benefits, often presents a challenge due to its diminished nutritional profile compared to full-fat varieties. Microalgae, such as Spirulina platensis and Chlorella vulgaris, are increasingly explored for their potential to fortify foods with essential nutrients. This study innovatively investigates the use of these microalgae to enhance the quality of reduced-fat labneh. The effect of incorporating different concentrations of both microalgae was investigated at different concentrations (0.25, 0.5, and 1%) on nutritional profile (including total solids, fat, protein, carbohydrates, essential amino acids, unsaturated fatty acids, pigments, and phenolic compounds), antioxidant activity, texture, sensory attributes, and viability of the starter culture. The findings revealed that 0.25 and 0.5% concentrations of both microalgae positively influenced the sensory characteristics of the labneh and significantly enhanced its nutritional profile. However, a 1% concentration negatively impacted sensory qualities. Chlorella vulgaris enrichment resulted in higher pH values but compromised texture attributes. Importantly, both microalgae varieties enhanced the viability of the starter culture during 21 days of refrigerated storage. The scanning electron microscope images provide visual evidence of the microstructural changes in labneh with varying concentrations of microalgae and over different storage periods. This research establishes the optimal concentrations for individual microalgae enrichment in reduced-fat labneh, offering valuable insights into their potential to improve both nutritional and sensory aspects. However, it's important to mention that while both microalgae have similar effects, they might differ in their specific impacts due to their unique nutritional profiles and physical properties. Therefore, further investigations could explore optimizing a microalgae mixture and its potential application in functional food development., (© 2024. The Author(s).)

This study investigates the postbiotic potential of extracellular products (ECPs) from Bacillus pumilus strains cultivated on microalgae-supplemented media. We assessed enzymatic and antimicrobial activities to select ECPs that enhance the digestive processes in gilthead seabream. Additionally, we explored the in vitro enzymatic capacity of the chosen postbiotics to hydrolyze macromolecules in microalgae. Finally, a feeding trial was conducted to determine the in vivo effects of the ECPs on Sparus aurata. In vitro enzymatic assays demonstrated diverse hydrolytic capacities among ECPs. All conditions exhibited antimicrobial activity against Photobacterium damselae subsp. piscicida, with variation in inhibitory effects against Vibrio harveyi and Tenacibaculum maritimum. Furthermore, in vitro assays revealed differences in protein hydrolysis and soluble protein concentration, influencing amino acid and reducing sugar release from microalgal biomass. These analyses facilitated a selection to test ECPs in vivo. Lastly, the in vivo experiment revealed no differences in the growth performance, nutrient utilization, and general metabolism of S. aurata fed the experimental diets. Dietary inclusion of postbiotics increased the activity of key digestive enzymes in fish compared to the control group, and particularly, values increased significantly when the fish were fed with the ECP-nanoparticulate-supplemented diet. In conclusion, the inclusion of microalgae in the culture media significantly influences the activity of extracellular products from B. pumilus strains, as evidenced in both in vitro and in vivo assays., (© 2024. The Author(s).)

The widespread use of non-ionic surfactant nonylphenol (NP) has led to significant water pollution, posing a threat to both ecological stability and human health. However, the efficient biodegradation method and system of NP-biodegradation remain complex scientific challenges. In this study, we isolated and characterized three Pseudomonas sp. strains SW-1 (Scenedesmus quadricauda-associated), ZL-2 (Ankistrodesmus acicularis-associated), XQ-3 (Chlorella vulgaris-associated), and one NP-degrading Cupriavidus sp. strain EB-4, which exhibited the ability to utilize NP as the sole carbon source. Furthermore, four consortiums of microalgae-bacterial, S. quadricauda and SW-1 (S-SW), A. acicularis and ZL-2 (A-ZL), C. vulgaris and XQ-3 (C-XQ), S. quadricauda and EB-4 (S-EB), were constructed to investigate their biodegradability and kinetic characteristics of NP degradation from water. The consortiums showed higher degradation efficiency compared to individual microalgae or bacteria. The C-XQ consortium exhibited the highest degradation rate, removing over 94% of NP within just seven days. The first-order model with the following order of degradation rate by consortiums was C-XQ (0.3960 d -1 ) > S-SW (0.3506 d -1 ) > A-ZL (0.1968 d -1 ) > S-EB (0.1776 d -1 ). Compared with the results of our previous study, the interaction between microalgae and bacteria is not a simple additive relationship. Our findings highlight the potential of an algal-bacterial consortium for the remediation of NP-contaminated environments., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Departing from the conventional axenic and heterotrophic cultures, our research ventures into unexplored territory by investigating the potential of photosynthetic microbiomes for polyhydroxybutyrate (PHB) synthesis, a biodegradable polyester that presents a sustainable alternative to conventional plastics. Our investigation focused on a cyanobacteria-enriched microbiome, dominated by Synechocystis sp. and Synechococcus sp., cultivated in a 3 L photobioreactor under non-sterile conditions, achieving significant PHB production-up to 28 % dry cell weight (dcw) over a span of 108 days through alternating cycles of biomass growth and PHB accumulation. Nile Blue staining and Transmission Electron Microscope visualization allowed to successfully confirm the presence of PHB granules within cyanobacteria cells. Furthermore, the overexpression of PHA synthase during the accumulation phase directly correlated with the increased PHB production. Also, gene expression changes revealed glycogen as the primary storage compound, but under prolonged macronutrient stress, there was a shift of the carbon flux towards favoring PHB synthesis. Finally, analysis through Raman, Fourier- transform infrared spectroscopy and proton Nuclear Magnetic Resonance further validated the extracted polymer as PHB. Overall, it was demonstrated for the first time the feasibility of using phototrophic microbiomes to continuous production of PHB in a non-sterile system. This study also offers valuable insights into the metabolic pathways involved., (Copyright © 2024. Published by Elsevier B.V.)

The environmental problems associated with the use of fossil fuels demand a transition to renewable sources for fuels and energy. A biorefinery approach has often been considered and microalgae as a feedstock has been pampered for its numerous possibilities to produce biofuels. Depending on the species and cultivation conditions, microalgae can produce fats, proteins and sugars. These raw materials can thus be utilized in the production of biofuels, bioenergy and biochemicals. For this reason, algal biofuels are considered as sustainable and renewable options for climate related challenges. However, there are many issues such as supply infrastructure, business and refinery opportunities, as well as their efficacy, tied to sustainable production of these energetic materials from algae. Thus, technical maturity, scalability, energy and material balance demands coupled with cost, nutrient resources demand, certification and legislation are needed to demonstrate the biorefinery opportunities of algal biomass valorisation. This paper therefore recommends that various consortiums tasked with algal biofuel projects should be chosen for a more holistic integrated multidisciplinary approach to address the advancement of algal biofuel technology., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Fishmeal and fish oil have been the main sources of protein and fatty acid for aquaculture fish. However, their increasing price and low sustainability have led the aquafeed industry to seek sustainable alternative feedstuffs to meet the nutritional requirements of fish and improve their health and performance. Plant proteins have been successfully used to replace fishery derivatives in aquafeeds, but the presence of anti-nutritional substances is a potential drawback of this approach. Thus, it has been reported that phytate breakdown can be caused by feed supplementation with exogenous phytase. The inclusion of microalgae has been proposed to improve gut functionality in fish fed diets with a high vegetable protein content. The aim of this study was to evaluate the effect on the growth and gut microbiota of European seabass (Dicentrarchus labrax) juveniles of a diet containing a blend of microalgae (Arthrospira platensis and Nannochloropsis gaditana) and different concentrations of phytase. An 83-day feeding trial was conducted, comprising four experimental diets with 2.5% microalgae and 500, 1,000, 2,000, or 10,000 phytase units (FTU)/kg feed and a microalgae- and phytase-free control diet. At the end of the trial, a significantly increased body weight was observed in fish fed the diet with the highest phytase concentration (10,000 FTU/kg) versus controls, although the gut bacterial composition did not differ from controls in alpha or beta diversity with either majority (Weighted UniFrac) or minority bacterial strains (Unweighted UniFrac). In comparison to the control group, the groups fed diets with 1,000 or 2,000 FTU/kg diets had a lower alpha diversity (Shannon's diversity index), while those fed diets with 500 FTU/kg or 1,000 FTU/kg showed distinct clusters in beta diversity (involving minority ASVs). According to these findings, the diet containing the 2.5% microalgae blend with 10,000 FTU/kg may be useful to increase the aquafeed quality and sustain the growth performance of juvenile European seabass., (© 2024. The Author(s).)

Phaeodactylum tricornutum ( PT ) is a microalgae extract that contains fucoxanthin and has been shown to enhance cognitive function in younger populations. The present study assessed if PT supplementation affects cognition in healthy, young-old, physically active adults with self-perceptions of cognitive and memory decline., Methods: Forty-three males and females (64.3 ± 6.0 years, 79.8 ± 16.0 kg, 27.0 ± 4.0 kg/m 2 ) with perceptions of cognitive and memory decline completed the double-blind, randomized, parallel-arm, placebo-controlled intervention clinical trial. Participants were counterbalanced by sex and BMI and randomly allocated to their respective 12-week supplementation interventions, which were either the placebo (PL) or 1100 mg/day of PT containing 8.8 mg of fucoxanthin (FX). Fasting blood samples were collected, and cognitive assessments were performed during the testing session at 0, 4, and 12 weeks of intervention. The data were analyzed by multivariate and univariate general linear model (GLM) analyses with repeated measures, pairwise comparisons, and mean changes from baseline analysis with 95% confidence intervals (CIs) to assess the clinical significance of the findings., Results: FX supplementation significantly affected ( p < 0.05) or exhibited tendencies toward significance ( p > 0.05 to p < 0.10 with effect sizes ranging from medium to large) for word recall, picture recognition reaction time, Stroop color-word test, choice reaction time, and digit vigilance test variables. Additionally, FX supplementation promoted a more consistent clinical improvement from baseline values when examining mean changes with 95% CIs, although most differences were seen over time rather than between groups., Conclusions: The results demonstrate some evidence that FX supplementation can improve working and secondary memory, vigilance, attention, accuracy, and executive function. There was also evidence that FX promoted more positive effects on insulin sensitivity and perceptions about sleep quality with no negative effects on clinical blood panels or perceived side effects. Additional research should investigate how FX may affect cognition in individuals perceiving memory and cognitive decline. Registered clinical trial #NCT05759910.

Food processing wastewater presents a considerable challenge for treatment owing to its elevated nitrogen and phosphorus levels. Nonetheless, it possesses inherent value attributed to its abundant nutrients and organic content. This study presents an innovative approach for treating food processing wastewater and reusing biomass. Initially, the secondary-treated wastewater undergoes flocculation and sedimentation, followed by reverse osmosis to ensure that the effluent meets reuse standards. Subsequently, reverse osmosis concentrates, generated at varying water recovery rates, are utilized for microalgae cultivation to recover nitrogen and phosphorus. Furthermore, this study highlights the potential of reverse osmosis concentrates in reducing the water demand for microalgae cultivation and in producing commercial-grade nutrients. The findings reveal that reverse osmosis achieves removal rates exceeding 90 % for both nitrogen and phosphorus and effluent meets reuse standards. Following seven days of cultivation, microalgae cultured in reverse osmosis concentrated water with an 80 % water recovery rate demonstrate denitrification and phosphorus removal rates of 73.88 % and 80.92 % respectively, with a biomass concentration of 563 mg/L and a protein yield of 128 mg/L. Moreover, a total volumetric energy yield of 10.08 kJ/L is obtained, facilitating energy valorization. In conclusion, this study offers practical solutions for wastewater treatment and resource recovery, enabling the attainment of zero discharge of pollutants while generating valuable resources through microalgae cultivation., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Microplastics (MPs) are emerging pollutants, causing potential threats to aquatic ecosystems and serious concern in aggregating with microalgae (critical primary producers). When entering water bodies, MPs are expected to sink below the water surface and disperse into varying water compartments with different light intensities. However, how light influences the aggregation processes of algal cells onto MPs and the associated molecular coupling mechanisms and derivative risks remain poorly understood. Herein, we investigated the aggregation behavior between polystyrene microplastics (mPS, 10 µm) and Chlorella pyrenoidosa under low (LL, 15 μmol·m -2 ·s -1 ), normal (NL, 55 μmol·m -2 ·s -1 ), and high light (HL, 150 μmol·m -2 ·s -1 ) conditions from integrated in vivo and in silico assays. The results indicated that under LL, the mPS particles primarily existed independently, whereas under NL and HL, C. pyrenoidosa tightly bounded to mPS by secreting more protein-rich extracellular polymeric substances. Infrared spectroscopy analysis and density functional theory calculation revealed that the aggregation formation was driven by non-covalent interaction involving van der Waals force and hydrogen bond. These processes subsequently enhanced the deposition and adherence capacity of mPS and relieved its phytotoxicity. Overall, our findings advance the practical and theoretical understanding of the ecological impacts of MPs in complex aquatic environments., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

To address two current issues in evaluating the toxicity of microplastics (MPs) namely, conflicting results due to species specificity and the ecological irrelevance of laboratory data, this study conducted a 10-day exposure experiment using a microalgal community comprising three symbiotic species. The experiment involved virgin and Benzo[a]pyrene-spiked micron-scale fibers and fragments made of polyethylene terephthalate (PET) and polypropylene (PP). The results showed that, from a physiological perspective, environmentally relevant concentrations of micron-scale MPs decreased saccharide accumulation in microalgal cells, as confirmed by ultrastructural observations. MPs may increase cellular energy consumption by obstructing cellular motility, interfering with nutrient uptake, and causing sustained oxidative stress. Additionally, MPs and adsorbed B[a]P induced DNA damage in microalgae, potentially further disrupting cellular energy metabolism. Ecologically, MPs altered the species abundance in microalgal communities, suggesting they could weaken the ecological functions of these communities as producers and affect ecosystem diversity and stability. This study marks a significant advancement from traditional single-species toxicity experiments to community-level assessments, providing essential insights for ecological risk assessment of microplastics and guiding future mechanistic studies utilizing multi-omics analysis., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Shuo Cheng reports financial support was provided by Japan Society for the Promotion of Science. Shuo Cheng reports a relationship with East China Normal University, Shanghai, China that includes: paid expert testimony. We with this apply for recusal. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Environmental remediation of heavy metals (HMs) is a crucial aspect of sustainable development, safeguarding natural resources, biodiversity, and the delicate balance of ecosystems, all of which are critical for sustaining life on our planet. The bioremediation of HMs by unicellular phototrophs harnesses their intrinsic detoxification mechanisms, including biosorption, bioaccumulation, and biotransformation. These processes can be remarkably effective in mitigating HMs, particularly at lower contaminant concentrations, surpassing the efficacy of conventional physicochemical methods and offering greater sustainability and cost-effectiveness. Here, we explore the potential of various engineered nanomaterials to further enhance the capacity and efficiency of HM bioremediation based on photosynthetic microorganisms. The critical assessment of the interactions between nanomaterials and unicellular phototrophs emphasised the ability of tailored nanomaterials to sustain photosynthetic metabolism and the defence system of microorganisms, thereby enhancing their growth, biomass accumulation, and overall bioremediation capacity. Key factors that could shape future research efforts toward sustainable nanobioremediation of HM are discussed, and knowledge gaps in the field have been identified. This study sheds light on the potential of nanobioremediation by unicellular phototrophs as an efficient, scalable, and cost-effective solution for HM removal., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Masson SAS.. All rights reserved.)

Bisphenols (BPs) are recognized as endocrine disrupting compounds and have garnered increasing attention due to their widespread utilization. However, the varying biological toxicities and underlying mechanisms of BPs with different functional groups remain unknown. In the present study, the toxic effects of four BPs (BPA, BPS, BPAF, and TBBPA) on a photosynthetic microalgae Chromochloris zofingiensis were compared. Results showed that halogen-containing BPs exhibited higher cellular uptake, leading to more severe oxidative stress, lower photosynthetic efficiency, and greater accumulation of starch and lipids. Specifically, TBBPA with bromine groups showed a greater toxicity than BPAF with fluorine groups, possibly due to the incomplete debromination in C. zofingiensis. Transcriptomic analysis revealed that halogen-containing BPs triggered greater number of differentially expressed genes (DEGs), and only 64 common DEGs were found among different BPs, indicating that the effects of BPs with different functional groups varied greatly. Genes involved in endocytosis, peroxisomes, and endoplasmic reticulum protein processing pathways were mostly upregulated across different BPs, while photosynthesis-related genes showed varied expression, possibly due to their distinct functional groups. Additionally, SIN3A, ZFP36L, CHMP, and ATF2 emerged as potential key regulatory genes. Overall, this study thoroughly explained how functional groups impact the toxicity and biodegradation of BPs in C. zofingiensis., Competing Interests: Declaration of Competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Chlorella vulgaris (CV) is a microalga with considerable nutritional value, containing high levels of protein, carotenoids, and polyunsaturated fatty acids, which have the potential to positively influence the productive performance and egg quality of laying hens. CV emerges as a more sustainable ingredient than soybean meal (SBM) as it can be produced locally and with fewer inputs. In this regard, a study was conducted with 48 H&N Brown Nick strain laying hens, at 19 weeks of age, over a period of 16 weeks. The hens were divided into four treatments, with 12 replicates each. The treatments consisted of providing four different diets: a control diet based on corn and SBM without the inclusion of CV, and three other diets with partial substitution of SBM by 2.5, 5, and 10% of CV. The results showed that the inclusion of CV in the diets did not significantly affect feed intake, feed conversion ratio, or egg production ( p > 0.05). In addition, moderate CV levels increased egg weight, while higher levels reduced it. Haugh units, yolk index, albumen index, egg surface area, specific density, and translucency were not affected ( p > 0.05), while shell index and shell thickness were lower in the groups that received the CV ( p < 0.0001). Yolk color improved significantly with increasing CV levels ( p < 0.0001), with darker, more intensely colored yolks at higher CV concentrations. The results of this study suggest that the incorporation of CV in the diet of laying hens had a limited impact on performance parameters. In addition, CV supplementation can positively influence egg quality and yolk color, although careful consideration of optimal levels is necessary to avoid negative effects on other parameters.

Microalgae are a promising feedstock with proven biostimulant activity that is enhanced by their biochemical components (e.g., amino acids and phytohormones), which turns them into an appealing feedstock to reduce the use of fertilisers in agriculture and improve crop productivity and resilience. Thus, this work aimed to isolate protein-rich microalgal mutants with increased biostimulant activity. Random mutagenesis was performed with Chlorella vulgaris, and a selection of protein-rich mutants were sorted through fluorescence-activated cell sorting (FACS), resulting in the isolation of 17 protein-rich mutant strains with protein contents 19-34% higher than that of the wildtype (WT). Furthermore, mutant F4 displayed a 38%, 22% and 62% higher biomass productivity, growth rate and chlorophyll content, respectively. This mutant was then scaled up to a 7 L benchtop reactor to produce biomass and evaluate the biostimulant potential of this novel strain towards garden cress seeds. Compared to water (control), the germination index and the relative total growth increased by 7% and 19%, respectively, after the application of 0.1 g L -1 of this bioproduct, which highlights its biostimulant potential.

A variety of shellfish toxin-producing Harmful Algal Blooms (HABs) occur every year in coastal temperate waters worldwide. These toxic HABs may cause lengthy (months) harvesting bans of mussels and other suspension feeding bivalves exposed to their blooms. To safeguard public health and the shellfish industry, European Union regulations request periodic monitoring of potentially toxic microalgae in seawater and phycotoxins in live bivalve molluscs from shellfish production areas. Monitoring of other toxic microalgae, e.g., fish killers, is based solely on cell counts. Morphological identification and quantification of microalgal cells with light microscopy is time-consuming, requires a good expertise, and accurate identification to species level (e.g., Pseudo-nitzschia species) may require electron microscopy. Toxicity varies among morphologically similar species; there are toxic and non-toxic strains of the same species. Molecular techniques using ribosomal DNA sequences offer a possibility to identify and detect precisely the potentially toxic genus/species. In an earlier project (MIDTAL), specific probes against rRNA sequences of all HAB taxa, known at the time of the project, affecting shellfish areas worldwide were designed, and those affecting Europe were tested and calibrated against rRNA extracts of clonal cultures and field samples. Microarray technology was adopted to relate to cell numbers the fluorescence signal from the reaction of all target species probes spotted in the microarray slides with those present in a single sample extract. The EMERTOX project aimed to develop a more automatic "Lab on a chip" (LOC) technology, including a non- (cell) disruptive water concentration system and biosensors for HAB cells detection. Here, calibration curves are presented against toxic microalgae (cultures and field samples) causing endemic and emerging toxicity events in Galicia (NW Spain) and Portugal. Results here relating cell numbers to electrochemical signals will be used in an early warning biosensor for toxic algae., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.)

The dinoflagellate Alexandrium pseudogonyaulax, a harmful algal bloom species, is currently appearing in increasing frequency and abundance across Northern European waters, displacing other Alexandrium species. This mixotrophic alga produces goniodomins (GDs) and bioactive extracellular substances (BECs) that may pose a threat to coastal ecosystems and other marine resources. This study demonstrated the adverse effects of A. pseudogonyaulax on four marine trophic levels, including microalgae (Rhodomonas salina), microzooplankton (Polykrikos kofoidii) and mesozooplankton (Acartia tonsa), as well as fish gill cells (RTgill-W1, Oncorhynchus mykiss), ultimately leading to enhanced mortality and cell lysis. Furthermore, cell-free supernatants collected from A. pseudogonyaulax cultures caused complete loss of metabolic activity in the RTgill-W1 cell line, indicating ichthyotoxic properties, while all tested GDs were much less toxic. In addition, cell-free supernatants of A. pseudogonyaulax led to cell lysis of R. salina, while all tested GDs were non-lytic. Finally, reduced egg hatching rates of A. tonsa eggs exposed to cell-free supernatants of A. pseudogonyaulax and impaired mobility of P. kofoidii and A. tonsa exposed to A. pseudogonyaulax were also observed. Altogether, bioassay results suggest that the toxicity of A. pseudogonyaulax is mainly driven by BECs and not by GDs, although further research into factors modulating the lytic activity of Alexandrium spp. are needed., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

This study evaluates the effectiveness of microalgal-based carbon-encapsulated iron nanoparticles (ME-nFe) in the removal of pharmaceutical compounds (PhACs) from water solutions and real municipal effluent at a laboratory scale. The investigated PhACs were chosen to represent different classes of synthetic drugs: antibiotics, anti-inflammatory drugs, antihypertensives, antiepileptics, neuroprotectors, and antidepressants. The adsorbent material was produced through hydrothermal carbonization (225 °C for 3 h), using microalgae grown on wastewater as the carbon source. ME-nFe showed heterogeneity in terms of porosity (with both abundance of macro and mesopores), a total pore volume of 0.65 mL g -1 , a specific surface area of 117 m 2  g -1 and a total iron content of 40%. Laboratory scale adsorption tests (1 g L -1 of nanoparticles with 2 min contact time) showed high removal for the most hydrophobic compounds. Removal efficiencies were high (over 98%) for Irbesartan, Ofloxacin and Diclofenac, promising (over 65-80%) for Clarithromycin, Fluoxetine, Lamotrigine and Metoprolol, but low for Gabapentin-Lactam and Propyphenazone (<20%). Electrostatic interactions between the drugs and the surface of the nanoparticles may account for the observed data, although additional removal mechanisms cannot be ruled out., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

This study investigated the bioenergy potential of Chlorella pyrenoidosa (CP) for use as fuel and carbon material through chemical and thermal characterization. The thermo-kinetic characteristics of Chlorella pyrenoidosa were assessed using isoconversional, linear regression, and non-linear regression approaches. The physicochemical analysis revealed high carbon (53.1 %), volatile (69.35 %), and low moisture (2.19 %), ash content (3.42 %). The results indicated that the non-linear model fitting method was the most accurate with the approximated activation energy (E α ) and pre-exponential Arrhenius constant (Ln A) were 124.92 ± 2.74 kJ/mol and 23.38 ± 4.63 min -1 , respectively. Additionally, the inclusion of sodium bicarbonate resulted in a significant increase in BET surface area. FTIR analysis revealed several functional groups beneficial for carbon material, while XRD analysis showed a broad peak correlated with an amorphous structure. This study highlighted the potential of Chlorella pyrenoidosa biomass for various applications, including carbon material and renewable fuel., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

Microalgal biomass is gaining increasing attention to produce high-value co-products. This study proposes integrating Chlorella microalgal biomass into a zero-waste biorefining system, aiming to produce biodiesel and biofertilizer. It investigates optimal conditions for ultrasound-assisted deep eutectic solvent (DES) pretreatment and lipid recovery to enhance the extraction of lipids. Optimal DES pretreatment was identified as a 1.6:1 acetic acid-to-choline chloride molar ratio, 0.36 g biomass loading, and 2.50 min of pretreatment. Lipid recovery succeeded with a 10-minute extraction time and a 1:3 methanol-to-butanol volume ratio. These conditions yielded biodiesel-quality lipids at 139.52 mg/g microalgal biomass with superior fuel characteristics. The de-oiled microalgal biomass residue exhibited promise as a lettuce biofertilizer, enhancing photosynthetic pigments but potentially reducing yields by 40 %. The study also notes changes in rhizosphere microbial communities, indicating both stimulatory and inhibitory effects on beneficial microbes. This study has the potential to enhance sustainability in energy, agriculture, and the environment., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Microalgae are the richest source of natural carotenoids-accessory photosynthetic pigments used as natural antioxidants, safe colorants, and nutraceuticals. Microalga Bracteacoccus aggregatus IPPAS C-2045 responds to stresses, including high light, with carotenogenesis-gross accumulation of secondary carotenoids (the carotenoids structurally and energetically uncoupled from photosynthesis). Precise mechanisms of cytoplasmic transport and subcellular distribution of the secondary carotenoids under stress are still unknown. Using multimodal imaging combining micro-Raman imaging (MRI), fluorescent lifetime (τ) imaging (FLIM), and transmission electron microscopy (TEM), we monitored ultrastructural and biochemical rearrangements of B. aggregatus cells during the stress-induced carotenogenesis. MRI revealed a decline in the diversity of molecular surrounding of the carotenoids in the cells compatible with the relocation of the bulk of the carotenoids in the cell from functionally and structurally heterogeneous photosynthetic apparatus to the more homogenous lipid matrix of the oleosomes. Two-photon FLIM highlighted the pigment transformation in the cell during the stress-induced carotenogenesis. The structures co-localized with the carotenoids with shorter τ (mainly chloroplast) shrunk, whereas the structures harboring secondary carotenoids with longer τ (mainly oleosomes) expanded. These changes were in line with the ultrastructural data (TEM). Fluorescence of B. aggregatus carotenoids, either in situ or in acetone extracts, possessed a surprisingly long lifetime. We hypothesize that the extension of τ of the carotenoids is due to their aggregation and/or association with lipids and proteins. The propagation of the carotenoids with prolonged τ is considered to be a manifestation of the secondary carotenogenesis suitable for its non-invasive monitoring with multimodal imaging., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

Microalgae growth-promoting bacteria (MGPB), both actinobacteria and non-actinobacteria, have received considerable attention recently because of their potential to develop microalgae-bacteria co-culture strategies for improved efficiency and sustainability of the water-energy-environment nexus. Owing to their diverse metabolic pathways and ability to adapt to diverse conditions, microalgal-MGPB co-cultures could be promising biological systems under uncertain environmental and nutrient conditions. This review proposes the recent updates and progress on MGPB for microalgae cultivation through co-culture strategies. Firstly, potential MGPB strains for microalgae cultivation are introduced. Following, microalgal-MGPB interaction mechanisms and applications of their co-cultures for biomass production and wastewater treatment are reviewed. Moreover, state-of-the-art studies on synthetic biology and metabolic network analysis, along with the challenges and prospects of opting these approaches for microalgal-MGPB co-cultures are presented. It is anticipated that these strategies may significantly improve the sustainability of microalgal-MGPB co-cultures for wastewater treatment, biomass valorization, and bioproducts synthesis in a circular bioeconomy paradigm., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier GmbH. All rights reserved.)

Microalgae are a promising bio-fertilizer that can be cultivated in municipal wastewater, where the organisms perform water purification by incorporation of nutrients and contaminants. Before bio-fertilization with wastewater-grown microalgae can be put into practice, its impact on the leaching of macronutrients and trace elements needs to be evaluated. Here, we studied the leaching behavior of a microalgae-fertilized soil against a control in column percolation setup. Microalgae were grown in real municipal wastewater supplemented with bromide for the analysis of within-cell Br - accumulation by time-of-flight secondary ion mass spectrometry. Dry biomass (45.0 g N kg -1 and 28.9 g P kg -1 ) was added to the topmost layer of the fertilized column at a level of 3 g biomass kg -1 on a whole soil basis. Column irrigation was equivalent to 3 years of precipitation in central Germany. The leaching of macronutrients and trace elements from the fertilized and control columns was largely identical. Except for P, depth profiles confirmed very low vertical translocation within the soil. This is held for total element contents as well as for operationally defined pools, suggesting that microalgae cultivated in municipal wastewater provide a slow-release fertilizer largely resistant to leaching. Mass spectrometric imaging gave clear evidence for bromide uptake by the microalgae, and pure cultures of the genus Scenedesmus showed that it was preferentially located in the cell membrane. Therefore, bromide could potentially be employed as a mineralization tracer in future studies on the use of microalgae as a bio-fertilizer., (© 2024 The Author(s). Journal of Environmental Quality published by Wiley Periodicals LLC on behalf of American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America.)

Eukaryotic microalgae are a diverse group of organisms that can be used for the sustainable production of a wide range of high value compounds, including lipids, flavours and dyes, bioplastics, and cosmetics. Optimising total biomass production often does not lead to optimal product yield and more sophisticated biphasic growth strategies are needed, introducing specific stresses to induce product synthesis. Genetic tools have been used to increase yields of natural products or to introduce new pathways to algae, and wider deployment of these tools offers promising routes for commercial production of high value compounds utilising minimal inputs., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Michael H. Cagney reports financial support was provided by Biotechnology and Biological Sciences Research Council. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Masson SAS.. All rights reserved.)

In this study, laboratory-scale cultivation of T. chuii and D. tertiolecta was conducted using Conway, F/2, and TMRL media to evaluate their biochemical composition and economic costs. The highest cell density (30.36 × 10 6  cells/mL) and dry weight (0.65 g/L) for T. chuii were achieved with Conway medium. This medium also produced biomass with maximum lipid content (25.65%), proteins (27.84%), and total carbohydrates (8.45%) compared with F/2 and TMRL media. D. tertiolecta reached a maximum cell density of 17.50 × 10 6  cells/mL in F/2 medium, which was notably lower than that of T. chuii. Furthermore, the media cost varied from US$0.23 to US$0.74 for each 1 L of media, primarily due to the addition of Na 3 PO 4 , KNO 3 , and cyanocobalamin. Thus, biomass production rates varied between US$38.81 and US$128.80 per kg on a dry weight basis. These findings comprehensively compare laboratory conditions and the costs associated with biomass production in different media. Additionally, this study explored the potential of T. chuii and D. tertiolecta strains, as well as their consortia with bacteria, for the degradation of various emerging pollutants (EPs), including caffeine, salicylic acid, DEET, imidacloprid, MBT, cimetidine, venlafaxine, methylparaben, thiabendazole, and paracetamol. Both microalgal strains demonstrated effective degradation of EPs, with enhanced degradation observed in microalgae-bacterial consortia. These results suggest that the symbiotic relationship between microalgae and bacteria can be harnessed for the bioremediation of EPs, thereby offering valuable insights into the environmental applications of microalgal cultivation., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Photobioreactors (PBRs) are used to grow the light-requiring microalgae in diverse commercial processes. Often, they are operated as continuous culture over months period. However, with time, biofouling layer develops on the inner surfaces of their walls. The fouling layer formation deteriorates the PBR performance as foulants reduce light penetration in it. Light is essential for photosynthetic cultures, and a deterioration in lighting adversely impacts algae growth and biomass productivity. Fouling requires a frequent shutdown to clean the PBR and add to the environmental impact of the operation by generating many wastewaters contaminated with the cleaning chemicals. Antibiofouling coatings could be used to modify the surfaces of existing and future PBRs. Therefore, transparent and non-toxic fouling-release coatings, produced using hydrogel technology, could transform the existing PBRs into efficient and enduring microalgae culture systems, requiring only the application of the coating to the inner walls, without additional investments in new PBRs., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

This study evaluated pulsed electric fields (PEF) and ultrasonication (US) combined with incubation to enhance cell disruption and protein extraction from Auxenochlorella protothecoides, comparing them to conventional high-pressure homogenization (HPH). A 5 h incubation enhanced protein yield by 79.4 % for PEF- and 27.2 % for US-treated samples. Extending the incubation to 24 h resulted in a total yield increase of 122 % for PEF (0.25 ± 0.03 kg EP  kg TP -1 ) and 51.9 % for US (0.20 ± 0.02 kg EP -1 kg TP -1 ). Autofermentation in untreated cells after 24 h resulted in protein release with lower yields than all other treated and incubated samples. While HPH had the highest protein yield (0.58 ± 0.04 kg EP  kg TP -1 ), PEF-incubation after 5 h (56.6 ± 5.3 MJ kg EP -1 ) and 24 h (49.5 ± 3.7 MJ kg EP -1 ) were 1.5 and 1.7-times more energy-efficient than HPH (82.9 ± 7.8 MJ kg EP -1 ). PEF combined incubation is an energy-efficient and targeted protein extraction method in heterotrophic A. protothecoides biorefinery., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

In this study, Chlorella and Scenedesmus were inoculated in biogas slurry medium with initial inoculum (OD 680 ) of 0.05, 0.1, 0.2, and 0.3, respectively, and 5% CO 2 was continuously injected. The study aimed to examine the carbon sequestration capacity of Chlorella and Scenedesmus , as well as the effectiveness of removing pollutants such as TN, TP, and COD in biogas slurry medium. Additionally, an economic efficiency analysis of energy consumption was conducted. The group with an initial inoculum (OD 680 ) of 0.3 for both types of microalgae exhibited better tolerance to pollutants, entered the logarithmic growth stage earlier, promoted nutrient removal, achieved higher energy efficiency, and reduced carbon emissions compared to the other groups. The highest carbon sequestration rates were 18.03% for Chlorella and 11.05% for Scenedesmus . Furthermore, Chlorella demonstrated corresponding nutrient removal efficiencies of 83.03% for TN, 99.84% for TP, and 90.06% for COD, while Scenedesmus exhibited removal efficiencies of 66.35% for TN, 98.74% for TP, and 77.71% for COD. The highest energy efficiency for pollutants and CO 2 removal rates for Chlorella were 49.51 ± 2.20 and 9.91 ± 0.44 USD -1 , respectively. In conclusion, the findings demonstrate the feasibility of using microalgae for simultaneous purification of biogas and biogas slurry.

Quantum dots (QDs) are widely utilized semiconductor nanocrystal materials with both nanotoxicity and composition-related toxicity. To determine the toxicological impacts and underlying mechanisms of QDs with different compositions on microalgae, carbon QDs (CQDs) and CdSe QDs were used in the present study. Results showed that QDs composed of CdSe were more toxic than QDs composed of carbon, which inhibited cell growth, with reductions in chl b content, chlorophyll fluorescence parameters, and increases in lipids and starch (two major storage substances). In addition, CdSe QDs elevated reactive oxygen species (ROS), resulting in oxidative damage, while CQDs had little effect on antioxidants. Comparative transcriptome analysis showed that gene expression was accelerated by CdSe QDs, and there was a compensatory upregulation of porphyrin metabolism, potentially to support chlorophyll synthesis. In addition, an MYB transcription factor was predicted by weighted gene co-expression network analysis (WGCNA) to serve as regulator in nanoparticle toxicity, while glutathione peroxidase (GPX) and dual-specificity tyrosine phosphorylation regulated kinases 2/3/4 (DYRK2/3/4) may be key mediators of the composition-related toxicity of CdSe QDs. This study highlights the critical role of QDs' composition in determining their impacts on aquatic microalgae, providing a theoretical reference for selecting appropriate QDs materials for various industrial applications., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Sulfadiazine (SDZ) is a kind of anti-degradable antibiotics that is commonly found in wastewater, but its removal mechanism and transformation pathway remain unclear in microalgal systems. This study investigated the effects of initial algae concentration and SDZ-induced stress on microalgal growth metabolism, SDZ removal efficiency, and transformation pathways during Chlorella sp. cultivation. Results showed that SDZ had an inhibitory effect on the growth of microalgae, and increasing the initial algal biomass could alleviate the inhibitory effect of SDZ. When the initial algal biomass of Chlorella sp. was increased to 0.25 g L -1 , the SDZ removal rate could reach 53.27%-89.07%. The higher the initial algal biomass, the higher the SOD activity of microalgae, and the better the protective effect on microalgae, which was one of the reasons for the increase in SDZ removal efficiency. Meanwhile, SDZ stress causes changes in photosynthetic pigments, lipids, total sugars and protein content of Chlorella sp. in response to environmental changes. The main degradation mechanisms of SDZ by Chlorella sp. were biodegradation (37.82%) and photodegradation (23%). Most of the degradation products of SDZ were less toxic than the parent compound, and the green algae were highly susceptible to SDZ and its degradation products. The findings from this study offered valuable insights into the tradeoffs between accumulating microalgal biomass and antibiotic toxic risks during wastewater treatment, providing essential direction for the advancement in future research and full-scale application., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:SHAN LIU reports financial support was provided by Shandong Provincial Natural Science Foundation. SHAN LIU reports financial support was provided by Yantai Educational-Local Synthetic Development Project. SHAN LIU reports financial support was provided by Key Laboratory for Crop and Animal Integrated Farming, Ministry of Agriculture and Rural Affairs. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Solid-state cultivation is a promising technology for algal biomass production, achieving high productivities without the need for dewatering. However, such systems have suffered from high evaporation, and capital costs. Here is described a hydrogel photobioreactor (hPBR) with the aim of reducing water demand in solid-state cultivations. Two designs are described with "Design A" offering better humidity control overgrowth conditions. A biomass productivity of 2.41gm -2 d -1 , and 2.87gm -2 d -1 when using physically crosslinked poly(vinyl alcohol) (pPVA) and chemically crosslinked PVA (cPVA) respectively were achieved with Chlorella vulgaris with a water demand around 0.44 kg g -1 of biomass. Over the 23 days of growth, the lipid content increased from 18.9 % to 56.6 % and 13.8 % to 43.2 % for pPVA and cPVA respectively, and the chlorophyll content decreased by more than 81 %. However, cell viability stayed high at over 98 % and surface coverage analysis showed good coverage of the gel surface., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Algal-based waste stabilisation ponds (WSP) are a common wastewater treatment system for small communities but have poor phosphorus removal. Under certain conditions algae in WSPs will perform 'luxury uptake' increasing their phosphorus content to over 3% (gP/gSS) by storing polyphosphate. For the first time in the literature this paper presents a systematic study which determines the conditions needed to maximise phosphorus accumulation within WSP biomass taking into account the interactions between key variables. The key variables of temperature, phosphorus concentration, light intensity, mixing intensity, organic load, and pH were evaluated in 40 batch factorial experiments using a WSP algal culture. All six variables examined had significant main effects or interactions on the phosphorus content of the biomass. These were incorporated into a regression equation which was successfully validated against independent data sets from the literature. The conditions required to maximise the phosphorus content of the biomass were predicted for both summer (high light and high temperature) and winter (low light and low temperature) scenarios. The required conditions were revealed to be high phosphorus concentration, high mixing intensity, no supplementary CO 2 addition, and low organic load. Interestingly, these conditions were consistent for both summer and winter suggesting that year-round treatment is possible. Practical methods of achieving these conditions were proposed. While further work will be needed to evaluate the effect of growth and potential influence of algal species, the findings presented provide a vital step towards developing a new phosphorus removal treatment process based on an enhanced understanding of environmental biotechnology.

Microalgae biotechnology holds great potential for mitigating CO 2 emissions, yet faces challenges in commercialization due to suboptimal photosynthetic efficiency. This study presents an innovative approach to improve CO 2 mass transfer efficiency in microalgae using carbonic anhydrase (CA) in an internal LED flexible air-lift photobioreactor. Optimal conditions initial inoculation with 3.55 × 10 6 cells/mL and 20 % CO 2 concentration, complemented by white LED lighting in Chlorella sp. CA regulated intracellular composition, enhancing chlorophyll, lipid, and protein contents. Metabolomics revealed elevated malic and succinic acids, associated with increased Ribulose 1,5-bisphosphate carboxylase oxygenase (RuBisCO) and Acetoacetyl coenzyme A (Acetyl-CoA) activities, facilitating efficient carbon fixation. CA also mitigated cellular oxidative stress by reducing reactive oxygen species (ROS). Furthermore, CA improved extracellular electron acceptor with currents surpassed CK. This CA-based microalgae biotechnology provides a foundation for future commercial applications, addressing CO 2 emissions., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Yun Liu reports financial support was provided by Science and Technology Innovation Special Foundation for Carbon Peak and Carbon Neutrality of Jiangsu Province. Yun Liu reports financial support was provided by National Natural Science Foundation of China. Liu, Y., Yao, D.D., Wu, L.Y., Tan, D., K. Tian., Zhang Y. has patent The invention relates to an airlift photobioreactor with built-in LED light source for microalgae culture issued to Yun Liu. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Nanophycology is recognized as one of the most important and widely used interdisciplinary sciences by creating a connection between nanotechnology on the one hand and phycology on the other hand. Algal nanoparticle biosynthesis is a starting point in studies and research related to nanophycology. Nanophycology consists of two parts, nano and phycology, and by taking advantage of the high potential of algae such as high biological safety, easy production, fast growth, and high stability in the phycology part of this science, which is also known as algology, algae nanoparticles synthesis and make this section related to nanotechnology. In this way, algae are known as factories of biological nanomaterials and cause the production of bio-stable nanotechnology and the removal of environmental pollutants released due to nanochemistry. Nanotechnology produced by algae in the science of nanophycology, due to algae's unique physical and chemical properties compared to other biological entities such as plants, fungi, and bacteria, is used in various fields including medicine, biorefining, purification Water, etc. In this review article, the most important goals of the science of nanophycology, including the biosynthesis of algal nanoparticles and the potential of these compounds in various fields of application, have been examined and discussed., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Inc.)

Contributing to the assessment of potential physiological changes in microalgae subjected to different concentrations and types of cyanotoxins, this study investigated the inhibitory effects of cyanotoxins on the growth, density, biomass, and ecotoxicity of Chlorella vulgaris. Chlorella vulgaris was exposed to crude extracts of cyanobacteria producing microcystin-LR (MC-LR), saxitoxin (SXT), anatoxin-a (ATX-A), and cylindrospermopsin (CYN) with initial concentrations of 5.0, 2.05, 0.61, and 1.42 μg.L -1 , respectively. The experiments were conducted under controlled conditions, and monitoring of growth and cell inhibition occurred at 24h, 48h, 72h, and 96h. Chlorophyll-a content and ecotoxicity assessment were conducted with samples collected after 96h of exposure to cyanotoxins. The growth assays of Chlorella vulgaris, with results expressed in terms of average growth rates (doublings/day), indicated the following order for cyanotoxins: SXT (2.03) > CYN (1.66) > MC-LR (1.56) > ATX-A (0.18). This assay revealed the prominent inhibitory potential of ATX-A on Chlorella vulgaris growth compared to the other toxins evaluated. Regarding the inhibition of the photosynthetic process, expressed in terms of the percentage inhibition of Chlorophyll-a, the following order for cyanotoxins was obtained: ATX-A (82%) > MC-LR (76%) > STX (46%) > CYN (16%). These results also indicated that among the cyanotoxins, ATX-A was the most detrimental to the photosynthetic process. However, contrary to the observations in the growth study, SXT proved to be more harmful than CYN in terms of Chlorophyll-a inhibition. Finally, the results of the toxicity assay revealed that only ATX-A and MC-LR exerted a chronic influence on Chlorella vulgaris under the investigated conditions., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

The production of renewable biofuel through microalgae and green technology can be a promising solution to meet future energy demands whilst reducing greenhouse gases (GHG) emissions and recovering energy for a carbon-neutral bio-economy and environmental sustainability. Recently, the integration of Energy Informatics (EI) technology as an emerging approach has ensured the feasibility and enhancement of microalgal biotechnology and bioenergy applications. Integrating EI technology such as artificial intelligence (AI), predictive modelling systems and life cycle analysis (LCA) in microalgae field applications can improve cost, efficiency, productivity and sustainability. With the approach of EI technology, data-driven insights and decision-making, resource optimization and a better understanding of the environmental impact of microalgae cultivation could be achieved, making it a crucial step in advancing this field and its applications. This review presents the conventional technologies in the microalgae-based system for wastewater treatment and bioenergy production. Furthermore, the recent integration of EI in microalgal technology from the AI application to the modelling and optimization using predictive control systems has been discussed. The LCA and techno-economic assessment (TEA) in the environmental sustainability and economic point of view are also presented. Future challenges and perspectives in the microalgae-based wastewater treatment to bioenergy production integrated with the EI approach, are also discussed in relation to the development of microalgae as the future energy source., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

With the growth of the aquaculture industry, antibiotic residues in treated wastewater have become a serious ecological threat. The effects of supplementation with diethyl aminoethyl hexanoate (DA-6) on the removal of tetracycline (TC), ciprofloxacin (CPFX), and sulfamonomethoxine (SMM) from aquaculture wastewater by different microalgae-based systems were examined and systematically analyzed. The results demonstrated that C. vulgaris -S395-2-C. rosea symbiont performed best under 0.2 mg L -1 antibiotic treatment for antibiotic removal. At 10 -7 M, DA-6 significantly enhanced C. vulgaris-S395-2-C. rosea symbiont removal of CPFX and SMM at 0.20 mg L -1 . The removal of TC, CPFX and SMM by this strain under optimal conditions was 99.2 ± 0.4 %, 86.3 ± 6.3 %, and 91.3 ± 5.7 %, respectively. These results suggest that DA-6 may act on microalgae-bacteria-fungi three-phase symbionts for the removal of multiple antibiotics from aquaculture wastewater., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Carbon supplementation strategies still have certain practical application constraints. Zn/Fe-based metal-organic frameworks (MOFs) nanoparticles that which are not toxic to Scenedesmus obliquus were successfully introduced into microalgal solutions to overcome low CO 2 solubility. The maximum specific surface area of MOFs reached 342.94 m 2 ·g -1 at a Zn/Fe molar ratio of 10/1. Under the optimal MOFs concentrations of 2.5 mg·L -1 , the conversion of inorganic carbon increased by 2.6-fold. When S. obliquuswas cultured in a MOFs-modified medium with 1.50 % CO 2 at 25 °C, the CO 2 mass transfer coefficient and mixing time reached 9.01 × 10 -3 min -1 and 55 s, respectively. The maximum chlorophyll-a content, biomass productivity, and CO 2 fixation efficiency reached 32.57 mg·L -1 , 0.240 g·L -1 ·d -1 and 21.6 %, respectively. Enriching CO 2 for ribulose-1,5-bisphosphate carboxylase/oxygenase carboxylation by MOFs may be the key to improving the photosynthetic efficiency of microalgae. This strategy could serve as a reference for improving the microalgal CO 2 fixation efficiency., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

Microalgae are a group of microorganisms, mostly photoautotrophs with high CO 2 fixation capacity, that have gained increased attention in the last decades due to their ability to produce a wide range of valuable metabolites, such as carotenoids and polyunsaturated fatty acids, for application in food/feed, pharmaceutical, and cosmeceutical industries. Their increasing relevance has highlighted the importance of identifying and culturing new bioactive-rich microalgae species, as well as of a thorough understanding of the growth conditions to optimize the biomass production and master the biochemical composition according to the desired application. Thus, this review intends to describe the main cell processes behind the production of carotenoids and polyunsaturated fatty acids, in order to understand the possible main triggers responsible for the accumulation of those biocompounds. Their economic value and the biological relevance for human consumption are also summarized. In addition, an extensive review of the impact of culture conditions on microalgae growth performance and their biochemical composition is presented, focusing mainly on the studies involving Pavlovophyceae species. A complementary description of the biochemical composition of these microalgae is also presented, highlighting their potential applications as a promising bioresource of compounds for large-scale production and human and animal consumption., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier Inc.)

This study aimed to investigate the recovery of agricultural biostimulants and biogas from microalgae treating wastewater, in the framework of a circular bioeconomy. To this end, municipal wastewater was treated in demonstrative raceway ponds, and microalgal biomass (Scenedesmus sp.) was then harvested and downstream processed to recover biostimulants and biogas in a biorefinery approach. The effect of microalgal biostimulants on plants was evaluated by means of bioassays, while the biogas produced was quantified in biochemical methane potential (BMP) tests. Furthermore, the fate of contaminants of emerging concern (CECs) over the process was also assessed. Bioassays confirmed the biostimulant effect of microalgae, which showed gibberellin-, auxin- and cytokinin-like activity in watercress seed germination, mung bean rooting, and wheat leaf chlorophyll retention. In addition, the downstream process applied to raw biomass acted as a pre-treatment to enhance anaerobic digestion performance. After biostimulant extraction, the residual biomass represented 91% of the methane yield from the raw biomass (276 mLCH 4 ·g -1 VS). The kinetic profile of the residual biomass was 43% higher than that of the unprocessed biomass. Co-digestion with primary sludge further increased biogas production by 24%. Finally, the concentration of CECs in wastewater was reduced by more than 80%, and only 6 out of 22 CECs analyzed were present in the biostimulant obtained. Most importantly, the concentration of those contaminants was lower than in biosolids that are commonly used in agriculture, ensuring environmental safety., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Microalgae is considered as sustainable and viable feedstock for biofuel production due to its significant advantages over terrestrial plants. Algal biofuels have received significant attention among researchers and energy experts owing to an upsurge in global energy issues emanating from depletion in fossil fuel reserves increasing greenhouse gases emission conflict among agricultural crops, traditional biomass feedstock, and potential futuristic energy security. Further, the exploration of value-added microalgae as sustainable and viable feedstock for the production of variety of biofuels such as biogas, bio-hydrogen, bioethanol, and biodiesel are addressed. Moreover, the assessment of life-cycle, energy balance, and environmental impacts of biofuel production from microalgae are briefly discussed. The present study focused on recent advancements in synthetic biology, metabolic engineering tools, algal bio refinery, and the optimization of algae growth conditions. This paper also elucidates the function of microalgae as bio refineries, the conditions of algae-based cultures, and other operational factors that must be adjusted to produce biofuels that are price-competitive with fossil fuels., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)