Search

The rapid increase in aquaculture over the last several decades has led to concerns about the environmental impact of fish feeds relying on marine resources for fishmeal (FM). We aim to assess Nannochloropsis sp. QH25 co-product as a viable and sustainable replacement for FM in juvenile rainbow trout, Oncorhynchus mykiss, feeds. We formulated four experimental diets: a reference (FM based), 33N, 66N, and 100N diet (33%, 66%, and 100% co-product replacement). Rainbow trout were randomly assigned to one of 16 tanks and randomly assigned an experimental diet to consume throughout the experiment (64 days total), with four replicate tanks per diet. We compared the phosphorus (P) and nitrogen (N) digestibility, emissions, and growth between diets and, compared six environmental impacts (biotic resource use (BRU), global warming potential (GWP), water use, land use, marine eutrophication potential (MEP), and freshwater eutrophication potential (FEP)) of each diet. Our results indicate that replacing FM with co-product did not significantly alter growth. P digestibility of the experimental and reference diets was comparable. BRU conversion ratio was significantly lower in the experimental diets. However, there were significantly higher water and land use conversion ratios but insignificantly higher results in GWP, MEP, and FEP between the reference and 100N diet.

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. • Simple regression tree model able to adapt to a wide variety of conditions. • The model is capable of successfully predicting pH under a different system conditions. • The simple structure of the model facilitates the adaptive tuning of control algorithms. • More than 100 days for 10 months for calibration and validation purposes. [ABSTRACT FROM AUTHOR]

Global increase in aquaculture production has created a need to reduce its environmental impacts. Nutrients could be recycled especially at land-based recirculating aquaculture systems (RAS) by cultivating green microalgae in aquaculture effluent. However, microalgae are difficult to harvest. As a multi-trophic solution, mussels could be used in harvesting microalgae. We tested three European freshwater mussels (duck mussel Anodonta anatina, swan mussel A. cygnea, and swollen river mussel Unio tumidus) for filtering two common green microalgae (Monoraphidium griffithii and Selenastrum sp.) grown in RAS effluent. Mussels decreased microalgal concentrations in the tanks 42–83% over three consecutive trials. Algal concentrations at the end of each trial were lowest for both microalgae in tanks containing Anodonta mussels. Clearance rates were higher for Anodonta mussels than for U. tumidus. Mussels biodeposited more microalgae to tank bottoms when M. griffithii was filtered. Ammonium concentration decreased or did not change in tanks with M. griffithii, but increased in tanks containing Selenastrum sp. These results suggest that of the tested species Anodonta mussels and M. griffithii show best potential for RAS effluent bioremediation application. We conclude that a co-culture of microalgae and unionid mussels could be used for recycling nutrients in aquaculture. [ABSTRACT FROM AUTHOR]

Thorium biosorption by a green microalga, Chlorella Vulgaris, was studied in a stirred batch reactor to investigate the effect of initial solution pH, metal ion concentration, biomass dosage, contact time, kinetics, equilibrium and thermodynamics of uptake. The green microalgae showed the highest Th adsorption capacity at 45 °C for the solution with a thorium concentration of 350 mg L−1 and initial pH of 4. The amount of uptake raised from 84 to 104 mg g−1 as the temperature increased from 15 to 45 °C for an initial metal concentration of 75 mg L−1 at pH 4. Transformation Infrared Spectroscopy (FTIR) was employed to characterize the vibrational frequency changes for peaks related to surface functional groups. Also, the scanning electron microscope (SEM) and energy-dispersive X-ray spectroscopy (EDX) were used to determine the morphological changes and elemental analysis of the biosorbent before and after the sorption process. The Langmuir isotherm was in perfect agreement with the equilibrium empirical data of thorium biosorption and the highest sorption capacity of the Chlorella Vulgaris microalgae was determined as 185.19 mg g−1. Also, the results of kinetic studies show that the thorium biosorption process follows a pseudo-second-order kinetic model. The negative value of ΔG0 indicates spontaneity and the positive values of ΔH0 indicate the endothermic nature of the adsorption process. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Over decades of development, the modern drug delivery system continues to grapple with numerous challenges, including drug loading inefficiencies, issues of immunogenicity, and cytotoxicity. These limitations restrict its application across various systems. Microalgae, as a natural resource, are not only abundant in bioactive compounds but also possess multiple biological properties, including active surface, photosynthesis capabilities, and excellent biocompatibility. These attributes make microalgae highly promising as carriers for targeted drug delivery, offering significant potential for the diagnosis and treatment of various diseases. Therefore, leveraging the exceptional properties of microalgae for drug delivery and optimizing their qualities is of paramount importance. This article focuses on elucidating the biological characteristics of microalgae and their applications in drug delivery, with a particular emphasis on emerging strategies for efficient drug loading and precise targeted delivery. Microalgae, as a natural biomaterial, hold immense potential for both commercial and clinical applications. [ABSTRACT FROM AUTHOR]

The human body can easily convert β‐carotene into retinol (a precursor of vitamin A), a significant ingredient in dietary supplements. The need for commercial natural pigment production, including β‐carotene, has led to intensive research in this area. Processing after biosynthesis is a vital stage that involves the use of nontoxic solvents, efficient mechanical disruption of cells, and the isolation of the required compounds. With the growing popularity of green extraction methods and the increasing market demand for carotenoids due to their health benefits, the use of clean, nontoxic, flash‐hydrolyzed biomass for carotenoid production presents a significant advantage. Furthermore, the remaining biomass can serve as a protein source for animal feed, thereby aligning with the principles of the biorefinery concept. In this study, our aim was to optimize the disruption of cells in two microalgal species using flash hydrolysis (FH). We applied two distinct levels of pressure and four separate temperature conditions over a brief residence time. Following this, we employed an ethanol extraction method to assess the efficiency of carotenoid pigment extraction. Flash hydrolysis is a chemical‐free subcritical water‐based continuous‐flow process, injected with wet biomass slurry at a high temperature (150–250 °C) for a very short time (8–12 s) to obtain bioproducts. In this study, we discovered that the pigment β‐carotene constituted 0.04 to 0.3% of the dry biomass in the case of Chlorella vulgaris. Bands of lutein and zeaxanthin were also observed in the thin layer chromatography (TLC) analysis of the treated slurry. This was achieved under conditions of an effective temperature of 200 °C and a pressure of 1700 psi. The Arthrospira platensis (1Tex), β‐carotene yield was 0.014 to 0.021% of dry biomass. Some lutein and zeaxanthin bands were also found in the treated slurry with an effective temperature of 150 °C and 1000 psi pressure. This study reports pigment extraction by FH for the first time. It is a viable process to scale up high‐value natural products like carotenoids from microalgae at the industrial level without adverse environmental impacts. Due to low residence time, the temperature does not have a negative effect on pigments; cell rupture was accomplished effectively using water as a solvent. A considerable amount of pigment could be recovered from microalgae at specific combinations of temperature and pressure depending on the type of cell wall that microalgae possess. [ABSTRACT FROM AUTHOR]

This research aimed to model and optimize the growth factors and enhance the lipid yield from Botryococcus braunii microalgae, and to design a system for obtaining biodiesel from these lipids as this does not compromise food security. Botryococcus braunii, grown on a modified Chu‐13 medium, reached the stationary phase after 27 days with a maximum cell count of 265 × 104 cells mL−1 after 27 days and maximum biomass yield of 725 mg L−1 after 30 days on modified Chu‐13 medium, which was higher than growth on Basal SAG medium. The maximum lipid content (18.47%) and lipid yield (4.46 mg L−1day) were obtained when B. braunii was cultivated on modified Chu‐13 medium after 30 days. Gas chromatography (GC) analysis for the lipids indicated that the highest percentages of SFAs (51.03%) and lowest percentages of monounsaturated fatty acids (MUFAs) (36.47%) and polyunsaturated fatty acids (PUFAs) (12.49%) were obtained by culturing B. braunii on modified Chu‐13 medium. The effect of different growth parameters (N2 level, NaHCO3, and CO2 concentrations) on growth yield was modeled by using D‐optimal design response surface methodology (RSM). [ABSTRACT FROM AUTHOR]

Growing environmental constraints on resources necessitates finding renewable and sustainable means of production. Microalgae provides a promising resource for feedstock in many bio-products and for waste utilization. Microalgae contain a variety of high-value products and are known for their bio-synthesis from waste sources. Increased industrial operations become a sustainable source of wastewater containing nutrient loads; in parallel, energy expenditures imparted to wastewater reclamation deteriorate the environment. To balance this, a circular economy that creates benefits to the environment and increases industrial productivity through planning out pollution/waste and recycling waste and materials back into use is essential. For example, various chemicals in wastewater can be used as sources of nutrient and bio-synthetic inducers in algal biorefining. This review discusses the required technical developments and knowledge gaps across multiple reuse methods for wastewater resources that support public health, industry, and environmental regulatory policies. Furthermore, this review surveys how industrial wastewater can serve as a sustainable resource, with chemical contents as a source of nutrient and substrate for algal cultivation and strategies necessary for biorefinery methods. Wastewaters have noxious contents, but various algal traits are relatively tolerant towards mixed chemicals, in some cases influencing biosynthetic pathways. The chemistry of wastewater varies depending on the stages and processes involved in product manufacturing, this variation require careful planning to ensure that the contents of the wastewater align with the specific targeted uses as a source of micro and macronutrients. [ABSTRACT FROM AUTHOR]

The three-chamber septic tank has become essential in the middle rural areas of China, although its drainage serves as a potential source of groundwater contamination. A photosynthetic electrochemical system using Chlorella vulgaris was developed to treat synthetic sewage, and the impact of environmental factors on treatment performance was investigated. The results showed that the removal efficiencies of chemical oxygen demand (COD), NH4+-N and PO43−-P reached maximum value under 1.00 times/day−1 hydraulic circulation, 0.3·g L−1 initial algae dosage and 4,350 Lux light intensity. When the optimal condition were applied to treat the effluent of three-chamber septic tank, the removal efficiencies of COD, NH4+-N , and PO43−-P were 61.95%, 88.32%, and 95.36%, respectively. This study provided an optional treatment technology of rural sewage, and future research should focus on the algae separation and recovery in practical applications. [ABSTRACT FROM AUTHOR]

There are no reports of production and characterization of polysaccharides in the genera Chlorella and Spirulina cultivated in seawater (SW) and brackish groundwater (BGW). Furthermore, there are few studies on the cultivation of these microalgae in seawater for this purpose. Therefore, the aim of the study was to evaluate the production and composition of polysaccharides in Spirulina sp. LEB 18 and Chlorella fusca LEB 111 grown in seawater and brackish groundwater, with and without nutrient supplementation. In this study, 100% SW and 100% BGW were used as nutrient sources and supplemented with different concentrations of nitrogen, phosphorus, iron, and EDTA sources that make up the Zarrouk/BG-11 culture media. Cultivating Chlorella fusca LEB 111 in SW, without the addition of nutrients, resulted in an approximately 23% increase in starch production (g/g). The cultivation of Spirulina sp. LEB 18 in SW and BGW, without the addition of nutrients, showed an increase in glycogen concentrations (50.5 and 40.75 g/100 gbiomass, respectively) and highest levels of exopolysaccharides (0.34 and 0.50 g/100 gbiomass, respectively) compared to the control. Moreover, exopolysaccharides compositional analysis has shown an increase in glucose content with salinity, and a decrease in xylose and glucuronic acid. This cultivation strategy demonstrates the viability of utilizing SW and BGW as alternatives to freshwater culture medium for microalgae that have high nutritional requirements, with the potential to produce exopolysaccharides. [ABSTRACT FROM AUTHOR]

The present study aims to investigate the potential for producing an aromatic hydrocarbon-enriched fuel from Scenedesmus sp. microalgae using low-cost zeolite in catalytic flash pyrolysis. The methodology adopted in this study involved the use of an analytical micropyrolyzer coupled with a gas chromatograph/mass spectrometer at 500 ºC to assess the effectiveness of the low-cost HZSM − 5 catalyst in deoxygenation, denitrogenation, and aromatization activities of volatile reaction products. The HZSM − 5 catalyst was synthesized using the hydrothermal method, employing low-cost precursor materials, rice husk ash, and diatomite residue as alternative silicon and aluminum sources. The oxygenated and nitrogenated volatile products in non-catalytic flash pyrolysis constituted 51.7% and 15.3%, respectively. Catalytic upgrading of pyrolysis vapors from Scenedesmus sp. microalgae was demonstrated by significant deoxygenation and denitrogenation activity, reaching up to 99%, while chemical industry-relevant classes experienced increased proportions: aromatic hydrocarbons by 5.8-fold, and aliphatic hydrocarbons by 1.7-fold. Around 78% selectivity for aromatic hydrocarbons was achieved, predominantly yielding BTEX (benzene, toluene, ethylbenzene, and xylene). Another significant finding is that 89.8% of the renewable hydrocarbons produced fall within the gasoline range (C5 − C12). This study conclusively indicates that the low-cost HZSM − 5 catalyst shows significant promise for producing high-quality bio-oil through the flash pyrolysis of Scenedesmus sp. microalgae. [ABSTRACT FROM AUTHOR]

The current study examines the phycoremediation potential cum biomass productivity and biomass quality of hitherto uninvestigated five algae in Bold's Basal Medium (BBM) of varying nitrogen (½ to 4 × N), phosphorus (½ to 4 × P), and both together (½ to 2 × NP) with varying N:P. All five algae displayed unique responses in biomass productivity, lipid yield and productivity, and nitrogen (N) and phosphorous (P) removal efficiency. Chlorolobion braunii exhibited the highest biomass productivity (107 to 109.23 mg/L/ day) in N-rich media (3 to 4 × N in BBM), and Monoraphidium contortum exhibited the highest biomass productivity (103.66 mg/L/day) in P-rich media (2 to 4 × P in BBM). All the algae exhibited a higher lipid yield and productivity in BBM with a reduced ratio of N:P (0.85 to 1.47) from a lesser addition of N (½ × N or NP in BBM). Monoraphidium contortum exhibited significantly higher lipid yield (44.38%) and productivity (35.94 mg/L/day) than other species. The lipid content of four species demonstrated high-quality biofuel properties. Halochlorella rubescens exhibited the maximum nitrogen removal efficiency of 96% (in BBM), and Monoraphidium contortum exhibited the maximum phosphorus removal efficiency of 94.4% (2 × NP in BBM). Overall, the experiments stand as a model for understanding the influence of variations in N and P concerning N:P on biomass productivity, lipid content, lipid productivity, and N and P removal rate and efficiency of algae for initial standardization of the culture protocols for further industrial trials. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Microalgae are a source of a wide variety of commodities, including particularly valuable pigments. The typical pigments present in microalgae are the chlorophylls, carotenoids, and phycobiliproteins. However, other types of pigments, of the family of water-soluble polyphenols, usually encountered in terrestrial plants, have been recently reported in microalgae. Among such microalgal polyphenols, many flavonoids have a yellowish hue, and are used as natural textile dyes. Besides being used as natural colorants, for example in the food or cosmetic industry, microalgal pigments also possess many bioactive properties, making them functional as nutraceutical or pharmaceutical agents. Each type of pigment, with its own chemical structure, fulfills particular biological functions. Considering both eukaryotes and prokaryotes, some species within the four most promising microalgae groups (Cyanobacteria, Rhodophyta, Chlorophyta and Heterokontophyta) are distinguished by their high contents of specific added-value pigments. To further enhance microalgae pigment contents during autotrophic cultivation, a review is made of the main related strategies adopted during the last decade, including light adjustments (quantity and quality, and the duration of the photoperiod cycle), and regard to mineral medium characteristics (salinity, nutrients concentrations, presence of inductive chemicals). In contrast to what is usually observed for growth-related pigments, accumulation of non-photosynthetic pigments (polyphenols and secondary carotenoids) requires particularly stressful conditions. Finally, pigment enrichment is also made possible with two new cutting-edge technologies, via the application of metallic nanoparticles or magnetic fields. [ABSTRACT FROM AUTHOR]

Microalgae are naturally rich in carbohydrates, lipids, proteins, pigments, minerals, and vitamins. These metabolites make them a renewable and sustainable source of bioactive compounds in nutraceuticals, food, feed for aquaculture, and biofuels. Genetic engineering of the existing strains remains crucial in utilising and upscaling microalgae-based biorefineries. CRISPR/Cas9, TALENs, ZFNs, and genetic transformation are the established tools utilised in microalgae genetic engineering. The common genetic transformation methods include electroporation, particle bombardment (biolistics), glass-bead agitation, and Agrobacterium-mediated transformation. Expression vectors and promoters are the prerequisites in genetic engineering. The present accessibility of genome sequences and omics datasets from a diverse array of microalgae species holds promise for catalyzing strategic progress in developing a superior microalgae strain suitable for numerous applications. This paper describes the genetic engineering to enhance microalgae biomass and metabolite production, particularly lipids. The advantages and precautions to fulfil the future application of genetically engineered microalgae are also reviewed and addressed.Article highlights: Strategic genetic engineering optimises microalgae strains for enhanced lipid synthesis and biomolecule production. CRISPR/Cas9 enables precise genome modifications in microalgae, enhancing their potential for various applications. Establishing regulatory frameworks for genetically modified (GM) microalgae is crucial for safe deployment. [ABSTRACT FROM AUTHOR]

Alternative aviation fuel is a crucial strategy to realize CO2 reduction for airline industry and catalytic pyrolysis is one of important processes to produce alternative aviation fuels. However, catalytic pyrolysis is still hindered by high production cost and deactivation of catalysts during catalytic conversion processes. In this study, composite catalysts Me-Y/MCM-41 (Me = La, Ce, and Ni) with hierarchical pores and metal oxide doping have been synthesized for catalytic pyrolysis of microalgal lipids to produce alternative aviation fuels. The hierarchically porous supports were prepared via the method of in situ growth of mesoporous materials on microporous zeolites. The characterization of as-synthesized catalysts indicated the presence of mesoporous and microporous phases in composite catalysts, and metal oxides were well dispersed on the surface of hierarchically porous supports with the doping amount of 7.7–11.5%. Catalytic activity of as-synthesized composite catalysts was also evaluated by Py-GC/MS using the feedstock of microalgal lipids. After catalytic pyrolysis, the selectivity of hydrocarbons in liquid biofuels significantly increased, especially for composite catalyst Ce-Y/MCM-41, while the composition of liquid biofuels was predominated by fatty acids in blank experiments without catalysts. Therefore, the main composition of liquid biofuels were alkanes, olefins, and aromatic hydrocarbons with high selectivity (above 70%) on kerosene-range products (C8–C16). This research provides necessary information about novel hierarchically porous composite catalysts for microalgae-based biorefinery and production of alternative aviation fuels by catalytic pyrolysis. [ABSTRACT FROM AUTHOR]

The study provides an innovative sustainable integrated route for efficient production of bio-oil through hydrothermal liquefaction of Chlorella sorokiniana grown in sewage water in an open race pond of 20,000-L capacity. The average specific growth rate and doubling time for C. sorokiniana was 0.1 h-1 6.9 h with reduction of 66.66%, ammonia 33.3% nitrate, 50% sulfate, 61.1% COD, and 58.8% of BOD respectively. The C. sorokiniana was harvested using auto flocculation cum decantation method and found to have 64.24% carbon and 12.08% hydrogen. The microalgae subjected to hydrothermal liquefaction in pilot scale 50 L HTL reactor for bio-oil production. 60.43 % of bio crude oil was obtained under optimized conditions. GCMS study reveals that bio-crude oil mostly contains hydrocarbons like amides, ketones, alcohols, amines, aldehydes, oxygenated compounds, fatty acids, and fatty acid methyl esters. The presence of alkanes, alkenes, aldehyde, amines, amides, esters, carboxylic acid, alcohols, and halo-compounds was also confirmed by FTIR. The presence of high concentration of hydrocarbons in the obtained bio-oil is an indicative of a high-quality oil that can be used in neat and blended form with conventional diesel fuel after some modification. [ABSTRACT FROM AUTHOR]

Microalgae have unique properties that allow them to thrive in unconventional spaces, making them suitable for areas that are not normally suitable for crop growth. This is due to their ability to multiply rapidly, grow easily and adapt to different environments at low cost. As a result, the present study aims to analyze the potential of microalgae as a source of agricultural nutrition, as well as the health benefits they can provide. The following research was conducted on an experimental scale using a closed system (photobioreactor) for the cultivation of microalgae, its physicochemical characterization of the cultures and dry biomass. It can be observed the percentages of 11 N; 1.4 P; 0.3 K and its micronutrients are essential for plant growth, since microalgae-based biofertilizers are considered as a sustainable, cost-effective and environmentally friendly alternative to chemical fertilizers. The use of microalgae biomass as a biofertilizer in agriculture can increase fertility, reduce soil erosion and nutrient loss, and improve soil quality over time. It also benefits plants, vegetables and greens, as it contains nitrogen, phosphorus and potassium, which are necessary for growth. [ABSTRACT FROM AUTHOR]

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 CO2 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. [ABSTRACT FROM AUTHOR]

In this study, Chlorella and Scenedesmus were inoculated in biogas slurry medium with initial inoculum (OD680) of 0.05, 0.1, 0.2, and 0.3, respectively, and 5% CO2 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 (OD680) 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 CO2 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. [ABSTRACT FROM AUTHOR]

The capability of microalgae had been studied for a long time; however, some basics of using microalgae as a biostimulant are still in question. In the present work, experiments were conducted to reply to questions such as (a) how does the application time affect the effects of microalgae treatments and (b) does variety or genetic variation cause differences in the effect of microalgae biomass application on the plants? The different times of application had different weightage on different parameters; however, when applied at the early reproductive stage the yield as well as the nitrogen % in grain was significantly affected. As per the comparison, the result suggested that varietal differences had negligible differences in biological yield, hexose content, and total phenol content. Furthermore, microalgae biomass treatment irrespective of the strain species or genus influences the biological photosynthate accumulation and nitrogen uptake or in short, the efficiency of uptake. Finally, the metabolomic analyses suggested the influence of the microalgae strains on the biochemical composition of the plants. [ABSTRACT FROM AUTHOR]

BACKGROUND: Microalga‐assisted wastewater treatment systems have gained attention for their efficiency in removing nutrients, chemical oxygen demand, toxic heavy metals and other dissolved compounds, while also producing valuable biomass and demonstrating high CO2 biofixation potential. The current research focuses on investigating the municipal wastewater phycoremediation and heavy metal biosorption ability of three indigenous freshwater microalgal strains: Tetradesmus reginae, Tetradesmus obliquus and Chlorella sorokiniana. RESULTS: The research findings indicate that the microalgal strains T. reginae, T. obliquus and C. sorokiniana exhibited notable performance in biomass accumulation. Specifically, the biomass accumulations were 2.215 ± 0.002, 1.143 ± 0.006 and 0.856 ± 0.021 g L−1, respectively, with initial culture biomasses ranging from 0.5 to 0.6 g L−1. These strains significantly reduced toxic heavy metals (As, 46.86–60.12%; Cd, 52.96–83.18%; Cr, 73.49–82.18%; and Pb, 95.38–96.25%), nutrients (NH4+ & NO3− 100% and PO43− 78–86.41%) as well as chemical oxygen demand (46.02–67.35%), and biosequestered CO2 (0.8–0.18 gCO2 L−1 d−1) during the growth period. Among the strains, T. reginae emerged as the top performer. The Fourier transform infrared spectra of the strain's biomass confirmed the presence of specific functional groups, such as CH, NH, OH and CN, which play a crucial role in ionising and reacting with toxic metal ions and protons in the wastewater. CONCLUSION: This study has shown that the isolated wild microalgal strains have promising phycoremediation and heavy metal adsorption characteristics. Moreover, they exhibit promising rates of CO2 biosequestration. These findings underscore the potential of microalga‐assisted wastewater treatment systems for efficient and eco‐friendly wastewater remediation, as well as biomass generation and CO2 mitigation. © 2024 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

Arctic freshwater ecosystems are on the “frontline” of climate change, but due to a lack of direct long‐term monitoring data, indirect approaches, such as algal‐based paleolimnology, must be used to reconstruct past limnological conditions. Our understanding of the responses of small‐ to mid‐sized Arctic lakes to climate warming has increased over the last ~30 years. However, until recently, little was known about even the basic limnological conditions of Canada's “Northern Great Lakes,” such as Lake Hazen, Great Bear Lake, and Great Slave Lake. In this summary, we show that a continuum of algal changes, observable in the sedimentary archives of shallow ponds to very large Arctic lakes, signals the crossing of key aquatic thresholds linked to changing ice covers and thermal regimes, declining wind speeds, and other climate‐related variables. With recent accelerated warming, even the largest and most resilient Arctic waterbodies are now fundamentally different than they were just a few decades ago. These changes will undoubtedly cascade throughout the food web leading to important changes for local Indigenous populations as well as the global community. [ABSTRACT FROM AUTHOR]

Space exploration and interstellar migration are important strategies for long-term human survival. However, extreme environmental conditions, such as space radiation and microgravity, can cause adverse effects, including DNA damage, cerebrovascular disease, osteoporosis, and muscle atrophy, which would require prophylactic and remedial treatment en route. Production of oral drugs in situ is therefore critical for interstellar travel and can be achieved through industrial production utilizing microalgae, which offers high production efficiency, edibility, resource minimization, adaptability, stress tolerance, and genetic manipulation ease. Synthetic biological techniques using microalgae as a chassis offer several advantages in producing natural products, including availability of biosynthetic precursors, potential for synthesizing natural metabolites, superior quality and efficiency, environmental protection, and sustainable development. This article explores the advantages of bioproduction from microalgal chassis using synthetic biological techniques, suitability of microalgal bioreactor-based cell factories for producing value-added natural metabolites, and prospects and applications of microalgae in interstellar travel. [ABSTRACT FROM AUTHOR]

Accurate detection of algae in microscopic image plays a crucial role in water quality monitoring. However, the existing object detection methods still face challenges in accurately detecting different categories of algae in microscopic image. In order to improve the accuracy, an improved YOLOv5s model is proposed for microalgae detection, by combining a Receptive Field Enhancement (RFE) module, the Wise‐IoU v3 dynamic non‐monotonic focal loss function, and a Dynamic head (Dyhead), which is termed receptive field enhancement wise‐IoU dyhead (RWD)‐you only look once (YOLO). Firstly, to detect microalgae of various scales, the Bottleneck in the C3 module of YOLOv5s is replaced with a more reasonable RFE module. Secondly, Wise‐IoU v3 is applied to enhance detection accuracy by assigning varying weights between high‐quality and low‐quality images. Finally, Dyhead is introduced to enhance the representation capacity of the detection head by integrating three attention mechanisms: scale awareness, spatial awareness, and task awareness. The proposed RWD‐YOLO model significantly enhances the accuracy of algae detection in microscopic image. Specifically, the experimental results on the microalgae dataset show that the RWD‐YOLO achieves an mAP@0.5 of 93.2% and an mAP@0.5:0.95 of 65.1%. Compared to the original YOLOv5s, mAP@0.5 and mAP@0.5:0.95 are improved by 3.7% and 5.7%, respectively. [ABSTRACT FROM AUTHOR]

Optogenetics, the method of light-controlled regulation of cellular processes is based on the use of the channelrhodopsins that directly generate photoinduced currents. Most of the channelrhodopsin genes have been identified in the green microalgae Chlorophyta, and the demand for increasing the number of functionally characterized channelrhodopsins and the diversity of their photochemical parameters keeps growing. We performed the expression analysis of cation channelrhodopsin (CCR) genes in natural isolates of microalgae of the genera Haematococcus and Bracteacoccus from the unique Arctic Circle region. The identified full-length CCR transcript of H. lacustris is the product of alternative splicing and encodes the Hl98CCR2 protein with no photochemical activity. The 5′-partial fragment of the B. aggregatus CCR transcript encodes the Ba34CCR protein containing a conserved TM1-TM7 membrane domain and a short cytosolic fragment. Upon heterologous expression of the TM1-TM7 fragment in CHO-K1 cell culture, light-dependent current generation was observed with the parameters corresponding to those of the CCR. The first discovered functional channelrhodopsin of Bracteacoccus has no close CCR homologues and may be of interest as a candidate for optogenetics. [ABSTRACT FROM AUTHOR]

One of the main threats to aquaculture is represented by microbial pathogens, causing mass mortality episodes in hatcheries, which result in huge economic losses. Among the many disinfection methods applied to reduce this issue, the use of chemicals and beneficial microorganisms (probiotics) seems to be the most efficient. The aim of this study is to test the efficacy of two of them: a chemical, peracetic acid (PAA), and a probiotic, Phaeobacter inhibens. Tests were run on microalgae of the species Isochrysis galbana (var T-ISO). For both remedies, the microalgae survival rate and final cell concentration (cell/mL) were monitored. PAA analysis tested six different concentrations of the chemical: 7.5 µg, 10 µg/L, 20 µg/L, 30 µg/L, 40 µg/L, and 60 µg/L. Meanwhile, P. inhibens was tested with a concentration of 104 CFU/mL. Analysis for both the remedies was conducted on a laboratory scale using glass flasks, and on an industrial scale inside photobioreactors (PBRs). Among all the treatments, the one with PAA dosed with a concentration of 60 µg/L gave the best results, as the culture reached a final density of 8.61 × 106 cell/mL. However, none of the remedies involved in the experiment harmed microalgae or their growth. The results match perfectly with the condition requested for the tested remedies: to obtain an optimal breakdown of pathogens without interfering with culture growth. These features make PAA and P. inhibens good candidates for disinfection methods in aquaculture facilities. [ABSTRACT FROM AUTHOR]

In order to explore the feasibility of using algae to treat the fly ash leachate from a safe landfill site, leachate samples taken from a certain safe landfill site in Wenzhou City were treated with two different microalgae, Chlorella vulgaris and Scenedesmus obliquus, and the effectiveness of each treatment was evaluated in terms of its efficiency of pollutant removal. The effects of conditions such as pretreatment of leachate by sterilization, the initial concentration of leachate, and the addition of nutrients on pollutant removal efficiency and algae growth were studied. Sterilization of the leachate was found to have a relatively small impact on the growth of C. vulgaris and S. obliquus, as well as the removal of pollutants from the leachate. Therefore, sterilization treatment may not be necessary for engineering applications. Algal growth and the removal of pollutants were optimal when the leachate was used at a concentration of 10%, but when the leachate concentration was 30% or higher, the growth of both algae was weakened. The inclusion of 0.2 g/L K2HPO4·3H2O and 0.06 g/L ammonium ferric citrate in the system led to higher algal growth and pollutant removal. The chlorophyll a levels of C. vulgaris and S. obliquus were 555.53% and 265.15%, respectively, and the nitrogen removal rates were also the highest, reaching 59.51% and 56.69%, respectively. This study optimized the cultivation conditions of a microalgae treatment leachate system, providing technical support and a theoretical basis for the practical engineering of a harmless treatment of leachate. [ABSTRACT FROM AUTHOR]

This research aims to propose management strategies to mitigate eutrophication caused by inefficient wastewater treatment plants in Colombia. The information analyzed was provided by environmental authorities such as IDEAM, CORANTIOQUIA, and CORNARE in Antioquia, where the average concentrations of phosphorus in wastewater from municipal, livestock, and industrial activities are 5.1, 30.6, and 29.1 mg P/L. The total nitrogen concentrations are 77, 143, and 121 mg N/L, respectively, surpassing the limit concentrations stated by the European Union, the United States, and Mexico, among others, while Colombia has not established its own limits. Including limitations for nutrient concentrations will align Colombia with the 2050 Sustainable Development Goals (SDGs), where microalgae species like Chlorella or Scenedesmus could be used in wastewater treatment systems for municipalities and industries. These microalgae can capture organic matter, nutrients, and greenhouse emissions and reduce the concentrations observed in natural water. They could also be an alternative for capturing heavy metals and some pollutants of emerging concern. In addition to the ecological and social benefits, the algal biomass could be valorized by transforming it into biological products such as fuels, fertilizers, and pigments when micropollutants are not present, reducing operational costs for treatment systems. [ABSTRACT FROM AUTHOR]

Nowadays, it is important to create the optimal technology for the absorption of flue gases with high CO2 content. In this regard, the aim of the investigation is to study the five different microalgae strains (Chlorella vulgaris, Chlorella ellipsoidea, Elliptochoris subsphaerica, Gloeotila pulchra, and Arthrospira platensis) under the influence of flue gases. The cultivation of microalgae was carried out in the atmosphere of flue gases with a gas flow rate of approximately 1 L·min−1 at high CO2 concentrations (3, 6, or 8%—from lower to higher concentrations), under continuous (24 h·d−1) illumination intensity of 200 µmol quanta·m−2·s−1 and a constant temperature of 27 ± 1 °C. The duration of the experiments was 12 days. Chlorella vulgaris and Chlorella ellipsoidea demonstrated the highest biomass growth rate at CO2 = 6% (0.79 and 0.74 g·L−1·d−1, respectively). The lowest growth rate (0.21 g·L−1·d−1) was achieved for Arthrospira platensis at CO2 = 3 and 6%. There was no significant drop in pH in the entire series of experiments. The results of microscopy showed a lack or a minimal number of dead cells in the strains under selected conditions. The obtained results can be used for further development of CO2 capture and storage technologies. [ABSTRACT FROM AUTHOR]

Algae is a promising sustainable feedstock for the generation of bio-crude oil, which is a sustainable alternative to fossil fuels, through the thermochemical process of hydrothermal liquefaction (HTL). However, this process also generates carbon particles (algae-derived carbon, ADC) as a significant byproduct. Herein, we report a brand-new and value-added use of ADC particles as a reinforcing agent for epoxy matrix composites (EMCs). ADC particles were synthesized through HTL processing of Chlorella vulgaris (a green microalgae) and characterized for morphology, average size, specific surface area, porosity, and functional groups. The ADC particles were subsequently integrated into a representative epoxy resin (EPON 862) as a reinforcing filler at loading levels of 0.25%, 0.5%, 1%, and 2% by weight. The tensile, flexural, and Izod impact properties, as well as the thermal stability, of the resulting EMCs were evaluated. It is revealed that the ADC particles are a sustainable and effective reinforcing agent for EMCs at ultra-low loading. Specifically, the ADC-reinforced EMC with 1 wt.% ADC showed improvements of ~24%, ~30%, ~31%, and ~57% in tensile strength, Young's modulus, elongation at break, and work of fracture (WOF), respectively, and improvements of ~10%, ~37%, ~24%, and ~39% in flexural strength, flexural modulus, flexural elongation at break, and flexural WOF, respectively, as well as an improvement of ~54% in Izod impact strength, compared to those corresponding properties of neat epoxy. In the meantime, the thermal decomposition temperatures at 60% and 80% weight loss of the abovementioned ADC-reinforced EMC increased from 410 °C to 415 °C and from 448 °C to 515 °C in comparison with those of neat epoxy. This study highlighted the potential of sustainable ADC particles as a reinforcing agent in the field of polymer matrix composite materials, which represented a novel and sustainable approach that would mitigate greenhouse gas remission and reduce reliance on nonrenewable reinforcing fillers in the polymer composite industry. [ABSTRACT FROM AUTHOR]

This work aimed to assess the potential efficacy of a novel polysaccharides-based extract as a green consolidant for the pictorial layer on marble substrates. Understanding its properties could lead to determining whether it can ensure the correct conservation and transmission of the cultural heritage. Four different types of marble specimens were prepared with paint based on malachite (egg, tempera grassa, rabbit glue, and linseed oil as binders). Colorimetric analyses, peeling tests, SEM-EDS, and FTIR spectroscopy were used to test the properties of the consolidant. Results reveal that no aesthetic changes occur when using the extract on painted surfaces and that the cohesive properties of most pictorial films increase after its application, confirming the consolidating effect. In conclusion, the use of an innovative green product for the restoration of marble-painted surfaces can be considered a possible good solution for consolidating treatment. Through this initial explorative research, we suggest an innovative approach to the protection of cultural heritage that doesn't cause harm to both the restorer's health and the environment. [ABSTRACT FROM AUTHOR]

Biomass is a valuable renewable energy adapted as an alternative to traditional fossil fuels. Apart from fuels, biomass is synthesized into highly valuable products that are used in various forms including biofuels, biochemical, bioproducts, packing material, and find practice in pharmaceutical, cosmetics, and nutraceuticals industries. Particularly, microalgae a third‐generation feedstock known for its rich carbon content possesses protein lipids and carbohydrates produces a variety of green products such as bioethanol, biohydrogen, biodiesel, and biomethane, and also fixes carbon emission to a certain amount in the atmosphere. However, microalgae conversion in the presence of a catalyst such as a metal–organic framework (MOF) yields high‐quality valuable products. A MOF is a porous crystalline material where the structure and pore size can be controlled making it suitable for catalytic reactions and appropriate conversion paths. This review briefly explains the prevailing status of microalgae as a sustainable biomass and features its components for microalgae biorefinery into valuable products and its application in the food industry. MOF properties, characteristics and various MOF‐based conversion technologies for biomass conversion with its application are elaborated. In addition, usage of value products produced from microalgae biorefinery in the food industry and its importance is elucidated. In addition, the challenges in integrating biorefinery processes with food industry operations and their solutions are also presented. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Microalgae are an evolving field to produce sustainable nutritious food with low environmental impact. To shape the emerging European value chain in a sustainable way, all actors and processes need to be considered. This article builds on the results of multi-stakeholder scenario workshops organised within the EC-H2020-funded project ProFuture. It investigates the roles different actors along the microalgae value chain hold to shape it. A qualitative analysis identified three actor groups: (1) microalgae producers and processors, and researchers who work with microalgae and their development, (2) policy makers, and large industrial players, who influence the political and economic possibilities of the microalgae value chain and (3) consumers, who play a key role in order to root sustainable microalgae food products in the market. The paper shows how these groups interlink and draws conclusions about their roles for shaping the European microalgae value chain. [ABSTRACT FROM AUTHOR]

A 12-week growth trial was conducted to evaluate the complete coreplacement of fish meal (FM) and fish oil (FO) in juvenile Florida pompano (Trachinotus carolinus) diets. Five open-formula experimental diets were formulated as iso-nitrogenous (approximately 46% crude protein) and isolipidic (approximately 15% crude lipid). It is assumed that Florida pompano lack the mechanisms for synthesizing sufficient LC-PUFA. In the FM/FO-free diets, to meet the necessary dietary intake of LC-PUFA, a commercially available Schizochytrium algal oil was used. Four diets were prepared from a basal mix, with spirulina and poultry by-product meal as the principal protein sources. They differed only in their oil source, containing fish oil (FO), algal oil (AO), soy oil (SO), or a 50/50 blend of algal oil and soy oil (A/S). The fifth experimental diet (control) was a standard open-formula FM diet. In addition to the experimental diets, two commercial closed-formula diets served as references. The seven diets, each with four replicates, were stocked with 20 Florida pompano (approximately 4 g) in each. The experimental open-formula diets were tested against the control using Dunnett's t-test, and different oil sources were tested against each other using orthogonal contrasts. The four experimental diets were each tested against the two reference diets with equivalency tests. Feed intake and survival were not different between the experimental diets and control. However, all production metrics were lower in the SO diet than the control. No other differences were observed between the FO, AO, and A/S diets and the control, or between the three diets. The feed conversion ratio (FCR) was higher in fish fed the SO diet than in fish fed the control diet, and no other differences were found. The protein efficiency ratio (PER) was higher in fish fed the control diet than in fish fed the experimental diets. Protein productive values (PPV) were similar to PER, except that the PPV in fish fed the AO diet was not different from the control. The contrasts revealed that the FO, AO, and A/S diets resulted in a lower FCR than the SO diet. The PER was higher in fish fed the AO diet, and lower in fish fed the SO diet. The PPV was higher in fish fed the AO diet than in fish fed the A/S and SO diets, but similar to that of fish fed the FO diet. There were striking differences in performance between the two commercial reference feeds, underscoring the importance of using well-defined open-formula diets as a reference or control. To our knowledge this is the first study to demonstrate that co-replacement of FM and FO can be achieved in Florida pompano by supplying an FM- and FO-free diet. The development of successful open-formula diets without FO will help spur innovation and sustainability in aquaculture production. [ABSTRACT FROM AUTHOR]

Abstract\nNovelty statementThis study explores the use of algae for phycoremediation, focusing on how Chlorella sorokiniana and Anabaena laxa detoxify water contaminated with captan, a common fungicide. The efficiency of these species in absorbing captan and the associated biochemical changes were evaluated to assess their potential for environmental protection. Microalgae were exposed to captan concentrations of 15 and 30 mg/L, and various parameters, including captan uptake, chlorophyll (Chl) a, carotenoid levels, and changes in metabolic profiles (soluble carbohydrates, organic acids, amino acids, and fatty acids), were measured. Results showed Anabaena had a higher captan absorption capacity (141.7 µg/g at 15 mg/L and 239.3 µg/g at 30 mg/L) compared to Chlorella (74.43 µg/g and 162 µg/g). Increased captan uptake reduced the growth of both species, as indicated by lower Chl a levels. Both species accumulated osmo-protectants and antioxidants as defense mechanisms, with soluble sugars increasing by 83.49% in Chlorella and 68.87% in Anabaena, and carotenoids increasing by 60.42% and 46.24%, respectively. Principal component analysis revealed distinct species-level responses, with Anabaena showing greater tolerance. The study concludes that both species can effectively remediate captan, with Anabaena being more efficient, indicating their potential for mitigating agrochemical impacts in aquatic environments and promoting sustainable agriculture and water management.This study uniquely demonstrates the superior capability of Anabaena laxa over Chlorella sorokiniana in remediating captan-contaminated water, highlighting distinct biochemical responses and enhanced tolerance mechanisms. By detailing species-specific metabolic adaptations, it underscores the potential of Anabaena for more effective phycoremediation. This novel insight into the differential resilience of microalgae species offers a promising approach to mitigating agrochemical pollution, advancing sustainable agriculture, and improving water management practices. [ABSTRACT FROM AUTHOR]

The productivity of microalgal cultures and their resilience to unfavorable conditions is largely determined by the availability of mineral nutrients, particularly nitrogen. Nitrogen starvation is a strong stressor that induces a broad range of responses in microalgae at the cell and cell population (culture) levels. These responses such as lipogenesis and secondary carotenogenesis are widely used in biotechnology to obtain valuable secondary metabolites of microalgae. It was believed that microalgal cells lack specific structures that function as long-term nitrogen depot, but recent studies assigned this role to microcrystalline inclusions constituted by nitrogenous bases (most often guanine). It is also known that purine microcrystals are biophotonic structures widespread in nature. These structures modify the intensity and spectral composition of radiation in illuminated cells and tissues of living organisms. In this regard, we studied (i) the dynamics of the formation of guanine crystals in the cells of green carotenogenic microalgae from the genus Coelastrella (C. thermophila NAMSU CM1/23 and C. rubescens IPPAS C-2066) depending on the availability of nitrogen in the medium and (ii) the effect of the presence of these crystals on cell resilience to high light intensity. Nitrogen-rich crystal inclusions were accumulated in cells when the cultures reached the stationary growth phase in a medium with ample nitrate nitrogen. During rapid growth, these inclusions were hardly detectable in the cells and disappeared during cultivation in the absence of nitrogen. Optical polarization microscopy and Raman microspectroscopy demonstrated that these nitrogen-rich inclusions are birefringent microcrystals composed of guanine. C. thermophila cells harboring abundant guanine crystals showed resistance to short-term (10–15 min) exposure to high-intensity light (600 µmol PAR quanta/m2/s). The results obtained are discussed in the context of the multifaceted role of guanine crystals in the stress tolerance of microalgae. [ABSTRACT FROM AUTHOR]

Haematococcus pluvialis is a microalga that can reduce the levels of inorganic and organic components in effluents, in addition to production of the high-value carotenoid astaxanthin. The present study proposed an integrated system for the simultaneous treatment of effluent from a Nile tilapia recirculation system and astaxanthin production using the microalga H. pluvialis. Cultures were developed in 2 L bottles, with freshwater previously treated and enriched with a modified Bold's Basal Medium (BBM). The experiment was carried out on a laboratory scale using a completely randomized experimental design with five treatments: control (100% BBM), E25 (25% Nile tilapia effluent + 75% BBM), E50 (50% Nile tilapia effluent + 50% BBM), E75 (75% Nile tilapia effluent + 25% BBM), E100 (100% Nile tilapia effluent), with three replicates for each condition. H. pluvialis could grow in all proportions of effluent from Nile tilapia cultivation. The use of effluent as culture medium (E100), despite having lower cell density and biomass, resulted in biomass with high astaxanthin content (10 mg g−1) and antioxidant activity (89% inhibition of DPPH radicals). Meanwhile, this integrated system significantly contributed to the effluent remediation (98% N and 91% P removal). H. pluvialis can be used for cost-effective treatment of aquaculture effluent with simultaneous production of astaxanthin, with potential application as aquafeed, in a holistic bioeconomy approach. [ABSTRACT FROM AUTHOR]

The marine prasinophyte green algae Pycnococcus provasolii and Pseudoscourfieldia marina represent the only extant genera and known species of the Pycnococcaceae. However, their taxonomic status needs to be reassessed, owing to the very close relationship inferred from previous sequence comparisons of individual genes. Although Py. provasolii and Ps. marina are morphologically different, their plastid rbcL and nuclear small subunit rRNA genes were observed to be nearly or entirely identical in sequence, thus leading to the hypothesis that they represent distinct growth forms or alternate life‐cycle stages of the same organism. To evaluate this hypothesis, we used organelle genomes as molecular markers. The plastome and mitogenome of Ps. marina UIO 007 were sequenced and compared with those available for two isolates of Py. provasolii (CCMP 1203 and CCAP 190/2). The Ps. marina organelle genomes proved to be almost identical in size and had the same gene content and gene order as their Py. provasolii counterparts. Single nucleotide substitutions and insertions/deletions were localized using genome‐scale sequence alignments. Over 99.70% sequence identities were observed in all pairwise comparisons of plastomes and mitogenomes. Alignments of both organelle genomes revealed that Ps. marina UIO 007 is closer to Py. provasolii CCAP 190/2 than are the two Py. provasolii strains to one another. Therefore, our results are not consistent with the placement of Ps. marina and Py. provasolii strains into distinct genera. We propose a taxonomic revision of the Pycnococcaceae and the erection of a new class of Chlorophyta, the Pseudoscourfieldiophyceae. [ABSTRACT FROM AUTHOR]

In recent years, algae have emerged as a promising feedstock for biofuel production, due to their eco-friendly, sustainable, and renewable nature. Various methods, including chemical, biochemical, and thermochemical processes, are used to convert algal biomass into biofuels. Pyrolysis, a widely recognized thermochemical technique, involves high temperature and pressure to generate biochar and bio-oil from diverse algal sources. Various pyrolytic processes transform algal biomass into biochar and bio-oil, including low pyrolysis, fast pyrolysis, catalytic pyrolysis, microwave-assisted pyrolysis, and hydropyrolysis. These methods are utilized to convert a range of microalgae and cyanobacteria into biochar and bio-oil. In this publication, we will discuss catalytic pyrolysis using mesoporous materials, such as SBA-15. Mesoporous catalysts have earned significant attention for catalytic reactions, due to their high surface area, facilitating the better distribution of impregnated metal. Pyrolysis conducted in the presence of a mesoporous catalyst is viewed more as efficient, compared to reactions occurring within the smaller microporous cavities of traditional zeolites. SBA-15 supports with incorporated Zr and/or Ce were synthesized using the direct hydrothermal synthesis method. The catalyst was characterized using structural and morphological technical analysis and utilized for the pyrolysis reaction of the algal biomass. [ABSTRACT FROM AUTHOR]

Research to date has mainly focused on the properties and efficiency of the production of selected, individual types of biofuels from microalgae biomass. There are not enough studies investigating the efficiency of the production of all energy sources synthesised by these microorganisms in a single technological cycle. The aim of this research was to determine the possibilities and efficiency of the production of hydrogen, bio-oil, and methane in the continuous cycle of processing T. subcordiformis microalgae biomass. This study showed it was feasible to produce these three energy carriers, but the production protocol adopted was not necessarily valuable from the energy gain standpoint. The production of bio-oil was found to be the least viable process, as bio-oil energy value was only 1.3 kWh/MgTS. The most valuable single process for microalgae biomass conversion turned out to be methane fermentation. The highest specific gross energy gain was found after applying a protocol combining biomass production, hydrogen biosynthesis, and subsequent methane production from T. subcordiformis biomass, which yielded a total value of 1891.4 kWh/MgTS. The direct methane fermentation of T. subcordiformis biomass enabled energy production at 1769.8 kWh/MgTS. [ABSTRACT FROM AUTHOR]

The list of standard abbreviations for JDS is available at adsa.org/jds-abbreviations-24. Nonstandard abbreviations are available in the Notes. The objective of this study was to evaluate the interaction of dietary carbohydrate profile and soybean meal (SBM) replacement with either Chlorella pyrenoidosa (CHL) or Spirulina platensis (SPI) on in vitro fermentation. This experiment was conducted as a randomized complete block design, with fermentation run (3 runs) considered as blocks. The treatments were arranged in a 2 × 5 factorial design, where the first factor was the carbohydrate profile, which was composed of diets containing 42.5% neutral detergent fiber (NDF) and 26.8% starch (HF-LS) or 26.8% NDF and 40.6% starch (LF-HS), and the second factor was the protein source, in which a control diet (100% SBM), partial replacement of SBM with CHL (1/2CHL) or SPI (1/2SPI), or total replacement of SBM with CHL or SPI were used. All experimental diets were formulated to have 17% crude protein. The ruminal fluid was collected from 2 lactating Holstein cows, buffered with Van Soest medium at a ratio of 1:2 and added to serum bottles containing 0.50 g of the experimental diets. Bottles were incubated at 39°C for 24 and 48 h in triplicate; headspace pressure was measured, along with gas collection for methane (CH 4) quantification at 0, 2, 4, 8, 16, 24, 36, and 48 h after incubation. The final medium was used to measure pH, ammonia, and VFA. After incubation, feed bags were recovered and used for estimation of dry matter (DM), NDF, and organic matter (OM) degradability. Statistical analysis was carried out using the MIXED procedure of SAS, with carbohydrate profile, protein source, assay, and their interactions as fixed effects, with run and bottle as random effects. Orthogonal contrasts were used to compare carbohydrate profile, algae species, carbohydrate profile × algae interaction, and linear and quadratic effects of SBM replacement with CHL or SPI. There was no interaction effect between carbohydrate profile and algae source. The LF-HS improved gas production, degradability of nutrients, and VFA, mainly increasing the production of butyrate and propionate. When compared with CHL, SPI had a greater degradability of nutrients and branched VFA, along with reduction in total gas production and tended to reduce total CH 4 yield. The replacement of SBM with algae linearly reduced the degradability of nutrients, along with a linear reduction in gas production. When replacement of SBM with only SPI was evaluated, SPI slightly reduced the degradability of nutrients; however, it promoted a linear reduction in CH 4 yield, as well as reduction in CH 4 yield by unit of degraded DM, NDF, and OM. In summary, there was no interaction of carbohydrate profile and protein source, which means that SBM replacement had a similar effect, regardless of dietary carbohydrate profile. Spirulina may be a more suitable algae source than Chlorella due to the potential to reduce CH 4. [ABSTRACT FROM AUTHOR]

Environmental pollution poses a critical global challenge, and traditional wastewater treatment methods often prove inadequate in addressing the complexity and scale of this issue. On the other hand, microalgae exhibit diverse metabolic capabilities that enable them to remediate a wide range of pollutants, including heavy metals, organic contaminants, and excess nutrients. By leveraging the unique metabolic pathways of microalgae, innovative strategies can be developed to effectively remediate polluted environments. Therefore, this review paper highlights the potential of microalgae-mediated bioremediation as a sustainable and cost-effective alternative to conventional methods. It also highlights the advantages of utilizing microalgae and algae-bacteria co-cultures for large-scale bioremediation applications, demonstrating impressive biomass production rates and enhanced pollutant removal efficiency. The promising potential of microalgae-mediated bioremediation is emphasized, presenting a viable and innovative alternative to traditional treatment methods in addressing the global challenge of environmental pollution. This review identifies the opportunities and challenges for microalgae-based technology and proposed suggestions for future studies to tackle challenges. The findings of this review advance our understanding of the potential of microalgae-based technology wastewater treatment. [ABSTRACT FROM AUTHOR]

Depleting global petroleum reserves and skyrocketing prices coupled with succinct supply have been a grave concern, which needs alternative sources to conventional fuels. Oleaginous microalgae have been explored for enhanced lipid production, leading towards biodiesel production. These microalgae have short life cycles, require less labor, and space, and are easy to scale up. Triacylglycerol, the primary source of lipids needed to produce biodiesel, is accumulated by most microalgae. The article focuses on different types of oleaginous microalgae, which can be used as a feedstock to produce biodiesel. Lipid biosynthesis in microalgae occurs through fatty acid synthesis and TAG synthesis approaches. In-depth discussions are held regarding other efficient methods for enhancing fatty acid and TAG synthesis, regulating TAG biosynthesis bypass methods, blocking competing pathways, multigene approach, and genome editing. The most potential targets for gene transformation are hypothesized to be a malic enzyme and diacylglycerol acyltransferase while lowering phosphoenolpyruvate carboxylase activity is reported to be advantageous for lipid synthesis. [ABSTRACT FROM AUTHOR]

Although established biotechnological applications of microalgae e.g., the production of high-value metabolites is based on axenic cultures, exploitation of the mutualistic consortia of microalgae and bacteria quickly comes to foreground, especially in bioremediation and wastewater treatment. This trend shifts the focus from genomic research of certain microalgal species to metagenomic studies of interactions between microalgae and bacteria in natural communities and in artificial consortia. Dissection of the genetic determinants of the robustness and productivity of the consortia become a hot research direction, too. Admirable contribution to this topic had been made by high-throughput sequencing (HTS), while recent breakthrough in this field was entailed by the advent and rapid development of the 3rd generation nanopore sequencing which becomes increasingly accurate while providing unprecedented sequencing performance. Recent progress of the Oxford Nanopore Technologies (ONT) enabled both classical metagenomic analysis of microalgal-bacterial communities based on whole metagenome sequencing as well as taxonomic and genetic profiling based on the amplicon sequencing. The parallel emergence of novel bioinformatic algorithms for processing the metagenomic datasets opened new opportunities for the analysis of structure and physiology of microalgal-bacterial communities. From the practical perspective, the new HTS techniques became a time- and labor-savers in discovery of new microalgae with a high potential for the accumulation of valuable metabolites, biodegradation of hazardous micropollutants, and biosequestration of nutrients from waste streams. Search for prokaryotic species boosting the biotechnological potential of eukaryotic microalgae via mutualistic interactions with them is another important goal. The insights from the both short-read and long-read metagenomics will form a solid foundation for the rational design of microalgal-bacterial consortia for biotechnology. In this review, we briefly outline the benefits of the long-read sequencing for structural and functional investigation of algal-bacterial consortia and summarize recent reports on using this approach for achieving the biotechnology-related goals. [ABSTRACT FROM AUTHOR]

Wastewater from different sources with excessive nutrient loading, which is a major contributor to eutrophication, can be a promising medium alternative for microalgae cultivation with effective removal of NH4+-N, PO43--P and organic matter. In this study, three groups of synthetic wastewater (SWW), an ammonium-rich stream (60 to 250 mg L-1 NH4+) containing a specific type of organic matter, such as petroleum effluent (SWW1: 300 mg L-1 glucose and 10 mg L-1 phenol), molasses wastewater (SWW2: 600 mg L-1 glucose), and agro-industrial wastewater (SWW3: no organic matters) were used for growing Chlorella sp. and for investigating its potential for nutrient removal as well as the production of biomass and lipid. The findings showed that Chlorella sp. grown in SWW2 (i.e., the auto/mixotrophic culture with 14 days) served as efficient feedstock for lipid production, and showed the maximum lipid content and yield of 53 % DCW and 188 mg L-1, respectively. Additionally, the maximum removal of 76 % NH4+-N was observed under this condition. Higher removal of NH4+-N with 100 % efficiency was seen in Chlorella sp. under SWW1 and SWW3 conditions. However, under SWW2 the cells had higher NH4+ uptake rate than that under SWW1 and SWW3, resulting in highest biomass productivity in SWW2 grown cells. The spent media after Chlorella sp. cultivation were used for growing the N2-fixing cyanobacterium Fischerella muscicola TISTR 8215 for the production of hydrogen. Among different spent media, F.muscicola TISTR 8215 cultivated in SWW1 spent medium obtained from 7-day Chlorella sp. cultivation had the highest hydrogen production of 200.8 µmol H2 mg-1 chlorophyll a. Overall, the present study employed biorefinery approach using the microalga biomass as feedstock for lipid production with subsequent utilization of spent medium for growing the cyanobacterium for enhanced production of hydrogen. [ABSTRACT FROM AUTHOR]

Search for novel best-performing starter feed ingredients is one of the main challenges of modern aquaculture industry. The goal of this article is to evaluate the effect of microalgae supplementation enriched with omega-3 polyunsaturated eicosapentaenoic acid and the powerful antioxidant fucoxanthin on growth performance of Red tilapia fry (Oreochromis mossambicus × Oreochromis niloticus). We formulated three experimental diets, using two strains of microalgae from our culture collection – Vischeria magna SBV-108 (Eustigmatophyceae), rich in eicosapentaenoic acid and Mallomonas furtiva SBV-13 (Chrysophyceae), rich in fucoxanthin – and their combination. Vischeria magna SBV-108 is a new strain which biochemical properties and growth characteristics have not been previously studied. Coppens Supreme-15 was used as a control diet. The best growth performance was recorded in eicosapentainoic acid enriched Diet 1 (10% w/w V. magna), that significantly (P<0.05) overperformed control feed on absolute growth, average growth, specific growth rate, feed conversion rate, protein efficiency ratio, protein productive value and energy productive value. Diet 3 (5% w/w V. magna and 5% w/w M. furtiva) and Diet 2 (10% w/w M. furtiva) were not significantly different from control at most parameters. Generally, supplementation of feed with microalgae rich in omega-3 eicosapentaenoic acid significantly improved Red tilapia fry growth parameters and overall feed performance, while supplementation of feed with microalgae rich in antioxidant fucoxanthin was not beneficial compared to the control. [ABSTRACT FROM AUTHOR]

For the first time, the cultivated diversity of microalgae in eroded soils in the northern part of the Fergana Valley in Uzbekistan has been studied based on both morphological and molecular genetic analysis. Ten strains of green microalgae (Chlorophyta) and one charophyte strain (Charophyta) were revealed. Only seven strains could be identified at the species level: Chlorella vulgaris, Chromochloris zofingiensis, Deuterostichococcus epilithicus, Pseudomuriella schumacherensis, and Pseudostichococcus monallantoides. Another four strains were identified only at the genus level and require further study: Bracteacoccus sp., Chlorosarcinopsis sp., Klebsormidium sp., and Tetratostichococcus sp. The low species diversity in the microalgae is likely due to both the low fertility of the eroded soils on the slopes, and the limitations of the culture-based approach that only reveals a fraction of the overall microbial diversity. Microalgal colonization of eroded soils in the arid foothill zone can be facilitated by various adaptations, such as small cell size and the production of extracellular polysaccharides, mycosporine-like aminoacids, and secondary carotenoids. The present work may contribute to the further development of highly functional microalgal consortia, which can lead to improvements and sustainable development of low-productivity, arid, and degraded terrestrial ecosystems. [ABSTRACT FROM AUTHOR]

We report a transformative epoxy system with a microalgae-derived bio-binder from hydrothermal liquefaction processing (HTL). The obtained bio-binder not only served as a curing agent for conventional epoxy resin (e.g., EPON 862), but also acted as a modifying agent to enhance the thermal and mechanical properties of the conventional epoxy resin. This game-changing epoxy/bio-binder system outperformed the conventional epoxy/hardener system in thermal stability and mechanical properties. Compared to the commercial EPON 862/EPIKURE W epoxy product, our epoxy/bio-binder system (35 wt.% bio-binder addition with respect to the epoxy) increased the temperature of 60% weight loss from 394 °C to 428 °C and the temperature of maximum decomposition rate from 382 °C to 413 °C, while the tensile, flexural, and impact performance of the cured epoxy improved in all cases by up to 64%. Our research could significantly impact the USD 38.2 billion global market of the epoxy-related industry by not only providing better thermal and mechanical performance of epoxy-based composite materials, but also simultaneously reducing the carbon footprint from the epoxy industry and relieving waste epoxy pollution. [ABSTRACT FROM AUTHOR]