Nannochloropsis Gaditana Research Articles

Increased shinorine production through the introduction of mycosporine-like amino acids biosynthetic genes from Pyropia yezoensis and Nostoc punctiforme into Nannochloropsis gaditana

Increased shinorine production through the introduction of mycosporine-like amino acids biosynthetic genes from Pyropia yezoensis and Nostoc punctiforme into Nannochloropsis gaditana

Multipurpose Fluorescent Nanocarriers: Environmental Behavior, Toxicity and Internalization on Marine Microalgae

AbstractEngineered nanomaterials (ENMs), such as silica mesoporous nanocapsules (SiNC), have emerged as a powerful tool for the controlled delivery and release of active compounds in various fields. However, the environmental impact of SiNC on marine biota, particularly when they enter the marine environment through wastewater effluents or direct release from maritime coatings, remains poorly understood. Studying their effects is thus crucial for environmental and human health protection, the development of safe‐by‐design ENMs, and informed policy‐making. This study aims to assess the ecotoxicological effects and internalization of industrially‐relevant SiNC in marine phytoplankton, namely on the microalgae Tetraselmis chuii, Nannochloropsis gaditana, and Isochrysis galbana, and diatoms Phaeodactylum tricornutum, and Chaetoceros calcitrans. For this purpose, a fluorescent nanocarrier (SiNC‐UMB) is developed by labeling the SiNC with the fluorescent natural dye umbelliferone (UMB). UV–vis and fluorescence spectroscopic analyses confirmed the successful loading of UMB into SiNC. Phytoplankton can internalize these ENMs, even at low concentrations, although adsorption to the cell wall can also occur. This confirms the internal exposure and growth inhibition observed in the microalgae. These findings highlight the potential of using SiNC‐UMB as a valuable tool for tracking their uptake and assessing their effects on marine biota and beyond.

NgAP2a Targets KCS Gene to Promote Lipid Accumulation in Nannochloropsis gaditana

The commercialization of algal lipids and biofuels remains impractical due to the absence of lipogenic strains. As lipogenesis is regulated by a multitude of factors, the success in producing industrially suitable algal strains through conventional methods has been constrained. We present a new AP2 transcription factor, designated as NgAP2a, which, upon overexpression, leads to a significant increase in lipid storage in Nannochloropsis gaditana while maintaining the integrity of other physiological functions. These provide methodologies for enhancing petroleum output and optimizing the carbon fluxes associated with specific products. An integrated analysis of RNA sequencing (RNA-seq) and chromatin immunoprecipitation sequencing (ChIP-seq) data has elucidated that the NgAP2a-induced up-regulation of critical genes is implicated in lipogenesis. Specifically, NgAP2a has been demonstrated to directly bind to the M1 motif situated within the promoter region of the KCS gene, thereby promoting the transcriptional activation of genes pertinent to lipid metabolism. In summary, we elucidate a plausible pathway whereby NgAP2a serves as a direct modulator of the KCS gene (Naga_100083g23), thereby influencing the expression levels of genes and molecules associated with lipid biosynthesis.

Effects of porosity and acidity on deoxygenation and denitrogenation in catalytic pyrolysis of protein-rich microalgae with metal-doped zeolites

The protein-rich defatted microalgae (Nannochloropsis gaditana) after lipid extraction was used as feedstock in catalytic pyrolysis to optimize economic returns of microalgae waste utilization. The effects of Ni- and Co-modified HZSM-5 on the formation of aromatic hydrocarbons (AHs), deoxygenation and denitrogenation in catalytic fast pyrolysis were studied via pyrolysis-gas chromatography and mass spectrometry (Py-GC/MS) at 500°C. Monometallic modified catalysts were synthesized by loading 0.5 wt%, 1 wt%, and 2 wt% of metal species onto HZSM-5 using ion exchange methods. The composition and pyrolysis pathways of primary volatiles detectable by gas chromatography (GC) were investigated, which included phenols, aliphatic hydrocarbons, AHs, acids, furans, N-heterocyclic compounds (N-HCs), amides and nitriles. The relative yields in AHs increased about 10.9 (0.5 wt% Ni/HZSM-5 or Ni0.5), 10.2 (Ni1), 6.8 (Ni2), 7.3 (Co0.5), 9.7 (Co1) and 7.8 (Co2) times compared to the relative yield from defatted microalgae pyrolysis. The doping of metals onto the HZSM-5 altered its porosity and acidity, leading to an impaired diffusion of reactants but also the creation of new acidic sites, which enhanced the selectivity towards monoaromatic hydrocarbons (MAHs) by aromatization and cleavage of N-containing heterocycles via the H radicals formation. Ni-loaded HZSM-5 outperformed Co-modified zeolite with respect to AHs production, deoxygenation and denitrogenation. The specific surface area (SBET) and pore volume were positively correlated with the formation of AHs, while strong acidity showed a strong positive correlation with the generation of nitriles and N-HCs. Relatively low loadings of Ni and Co (0.5–1 wt%) on HZSM-5 (Si/Al = 23) were recommended to decrease the N-containing compounds in pyrolysis vapors from defatted microalgae. The findings may shed light on the development of a high-performance HZSM-5 catalyst for the production of AHs and denitrogenation from protein-rich defatted microalgae.

Microalgae and phytase dietary supplementation improved growth and gut microbiota in juvenile European seabass (Dicentrarchus labrax)

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.

Structural and functional alterations under stress conditions by contamination: A multi-species study in a non-forced multi-compartmented mesocosm

Despite the existing connectivity and heterogeneity of aquatic habitats, the concept of interconnected landscapes has been frequently overlooked in ecotoxicological risk assessment studies. In this study, a novel mesocosm system, the HeMHAS (Heterogeneous Multi-Habitat Assay System), was constructed with the potential to assess structural and functional changes in a community resulting from exposure to contaminants, while also considering the complex ecological scenarios. Fish (Sparus aurata), shrimp (Palaemon varians) and three species of marine microalgae (Isochrysis galbana, Nannochloropsis gaditana and Tetraselmis chuii) were used as test organisms. Other species, such as Artemia sp. and macroalgae were also introduced into the system as environmental enrichment. All the species were distributed in five interconnected mesocosm compartments containing a copper gradient (0, 1, 10, 100 and 250 μg/L). The mobile fish avoided the copper contaminants from 1 μg/L (24 h-AC50: 4.88 μg/L), while the shrimp avoided from 50 μg/L (24 h-AC50: 136.58 μg/L). This finding suggests interspecies interactions influence habitat selection in contaminated environments, potentially jeopardizing population persistence. Among the non-motile organisms, the growth and chlorophyll content of the microalgae were concentration dependent. The growth of I. galbana was more sensitive (growth inhibition of 50 % at the highest concentration) in contrast to N. gaditana (30 % inhibition at the highest concentration) and T. chuii (25 % inhibition at the last two highest concentrations). In summary, the mesocosm HeMHAS showed how contamination-driven responses can be studied at landscape scales, enhancing the ecological relevance of ecotoxicological research.

Biodiesel derived from the microalgae Nannochloropsis gaditana and Haematococcus pluvialis: Physicochemical and tribological properties

The physicochemical and tribological propertie of two biodiesels derived from Nannochloropsis gaditana and Haematococcus pluvialis microalgae were evaluated, and the impact of their fatty acid methyl esters (FAMEs) on the aforementioned properties was also evaluated. The H. pluvialis biodiesel exhibited reduced friction and wear compared to the N. gaditana counterpart, attributed to its lower degree of unsaturation and higher content of chain length of 17–18, which enhances the adsorption of stronger and thicker tribofilms. Additionally, the higher ratio of monounsaturated to total saturated FAME content contributed to this outcome. The content of polyunsaturated fatty acids decreased the viscosity and increased the end thermal degradation temperature.

Economically viable bioprocess for inclusion of microalga Nannochloropsis gaditana in aquaculture feeds: Evaluation of antioxidant addition in preventing lipid oxidation during storage

The rising prices of fishery derivatives limits their use in aquafeeds. Therefore, other alternatives are used to replace those ingredients. Among them, microalgae are of great interest both as an ingredient and as a potential stabilising agent against lipid oxidation. This study evaluates on the use of Nannochloropsis gaditana to prevent lipid oxidation in a set of 12 aquafeeds over 540 days of storage. Aquafeeds were formulated with/without 15 % N. gaditana combined with two antioxidants −butylhydroxytoluene (25–150 mg·kg-1) or vitamin E (500–3000 mg·kg-1). The effect of i) storage period, ii) presence of microalgae and iii) antioxidant addition on lipid oxidation was assessed. Results showed higher fatty acid degradation in diets lacking microalgae. The microalgae supplemented diets is enough for preserving feeds presenting the highest antioxidant effect at the end, without significant differences with the microalgae-supplemented feeds and those including antioxidants after 540 days of storage.

A combination of metabolomics and microbiome analyses reveal the modulation of lipid metabolism effect of Nannochloropsis gaditana polysaccharides on alcohol-induced dyslipidemia in mice

Mining the nutritional function of Nannochloropsis gaditana is crucial for its development and utilization. This study evaluated the protective effect of purified Nannochloropsis gaditana polysaccharides (NPS) on alcohol-induced dyslipidemia. The study used a liquid alcohol diet and an NPS intervention of 200 mg/kg.bw and 400 mg/kg.bw for 5 weeks. Compared with the model group (MC), the NPS group had a lower triglyceride (TG) and total cholesterol (TC). The relative abundance of probiotics Akkermansia, Bifidobacterium and Ligilactobacillus were significantly higher in NPS groups than those in the model group. Compared with the MC, NPS group had higher serum phosphatidylcholine/phosphatidylethanolamine (PC/PE) ratio and lower ceramide. Moreover, the expression of lipidolysis-related genes such as PGC1α and CPT-1A in the NPS group were significantly higher compared to MC. In summary, NPS attenuated ethanol-induced dyslipidemia probably by regualating gut bateria and serum metabolites, which could serve as a potential prebiotic.

Metabolomics Reveals the Impact of Overexpression of Cytosolic Fructose-1,6-Bisphosphatase on Photosynthesis and Growth in Nannochloropsis gaditana.

Nannochloropsis gaditana, a microalga known for its photosynthetic efficiency, serves as a cell factory, producing valuable biomolecules such as proteins, lipids, and pigments. These components make it an ideal candidate for biofuel production and pharmaceutical applications. In this study, we genetically engineered N. gaditana to overexpress the enzyme fructose-1,6-bisphosphatase (cyFBPase) using the Hsp promoter, aiming to enhance sugar metabolism and biomass accumulation. The modified algal strain, termed NgFBP, exhibited a 1.34-fold increase in cyFBPase activity under photoautotrophic conditions. This modification led to a doubling of biomass production and an increase in eicosapentaenoic acid (EPA) content in fatty acids to 20.78-23.08%. Additionally, the genetic alteration activated the pathways related to glycine, protoporphyrin, thioglucosides, pantothenic acid, CoA, and glycerophospholipids. This shift in carbon allocation towards chloroplast development significantly enhanced photosynthesis and growth. The outcomes of this study not only improve our understanding of photosynthesis and carbon allocation in N. gaditana but also suggest new biotechnological methods to optimize biomass yield and compound production in microalgae.

Screening for alkaliphilic microalgae for carbon capture from ambient air and food production

SummaryThe production of alkaliphilic microalgae can contribute to address the challenging cost of using pure carbon dioxide in large reactors. At high pH values, carbon dioxide is rapidly scavenged and the supply rates of dissolved inorganic carbon from the atmosphere to alkaline media are high. The present study aimed to identify microalgal strains that can cope with high alkalinity and aeration rates. Eight strains were studied and the microalgae Chlorella vulgaris, Scenedesmus almeriensis and Nannochloropsis gaditana were the only ones that were able to grow under these conditions. Their biomass productivities using laboratory‐scale bubble columns with no pH control and high aeration flow were 0.20 ± 0.03, 0.24 ± 0.03 and 0.08 ± 0.01 g·L−1·day−1, respectively. The production of the two former was scaled up to pilot‐scale bubble columns. Overall, the amount of atmospheric carbon dioxide that was transformed into biomass was in the range of 10%–30%, depending on the strain used and the photobioreactor setup. The biomass was rich in proteins and β‐carotene, both valuable products, highlighting the potential production of food ingredients while capturing carbon dioxide from the atmosphere.

Biodiesel production from the microalgae Nannochloropsis gaditana: Optimization of the transesterification reaction and physicochemical characterization

The current environmental scenario has encouraged the study of renewable and competitive alternative feedstocks for biodiesel production. Microalgae present a significant opportunity as a feedstock that does not require arable land and can be cultivated using wastewater. The paper investigates the optimization of biodiesel production from microalgae Nannochloropsis gaditana bio-oil using response surface methodology and also analyzes the main physicochemical properties of the bio-oil. It was confirmed that this methodology is suitable for materials with low homogeneity. The model is also adequate for determining optimal experimental conditions, resulting in a FAME content of 87.25 %. The biodiesel's physicochemical properties were analyzed. It was discovered that the high degree of unsaturation in the microalgae bio-oil's chemical structure resulted in a narrower temperature range for its application compared to other vegetable sources.

Production of techno-functional proteins and plant biostimulants from Nannochloropsis gaditana

Nannochloropsis gaditana is produced mainly for its lipid content and fatty acid profile. However, its protein content is comparable to or even higher than that of most conventional protein sources. In this work, the microalga N. gaditana BEA 1202B purchased from the Spanish Bank of Algae (BEA) was produced using 3.4 m3 tubular photobioreactors achieving a biomass productivity of 0.1 g L−1·day−1 and a protein content of 29.2 ± 4.5 % (d.w.). The biomass produced was used as a source of proteins; the protein recovery was optimised following a response surface methodology. Under optimal conditions, which were solubilisation at pH = 10.2 and precipitation at pH = 3.1, the protein recovery yield was 17.5 g·100 g−1. The extract exhibited a water-holding and an oil-holding capacity of 2.1 and 3.0 g g−1, respectively. The leftovers from protein extraction were assessed as plant biostimulants and demonstrated a positive effect on root development, weight gain, and chlorophyll retention. The process described in this work presents a sustainable and environmentally friendly approach to harness the potential of the microalga N. gaditana in producing high-value food proteins and plant biostimulants. The integration of this microalgal-based biorefinery concept could contribute to more sustainable agriculture and address the growing global demand for protein-rich products and plant promoters.

Unwrapping the (glyco-)lipidome in the microalgae Microchloropsis gaditana: Effects of eco-friendly extraction methods

Microalgae have recently captivated worldwide attention because of their extraordinary lipid composition, which includes essential omega-3 and omega-6 long-chain polyunsaturated fatty acids (LC-PUFA), neutral lipids, and more complex lipids (glycolipids and phospholipids), as well as eicosanoids. To explore this further, we present a novel (glyco-)lipidomics strategy, including a green chemistry extraction approach, liquid chromatography high-resolution mass spectrometry (LC-HRMS) lipid profiling, and a comprehensive data evaluation workflow. Using untargeted lipidomics based on LC-HRMS approaches, we studied the lipid composition up to the molecular species level of the microalgae Microchloropsis gaditana (formerly Nannochloropsis gaditana), focusing on the distribution of saturated, monounsaturated, and polyunsaturated fatty acids in different lipid classes. Our analysis successfully identified 520 lipid molecular species from 18 lipid classes. Regarding fatty acid composition, our primary focus was on elucidating the distribution of LC-PUFA across the different microalgal lipid classes. This particular strategy holds potential as it may unravel the use of microalgal lipids as innovative sources of food ingredients. Our findings show that LC-PUFA are relatively elevated in membrane lipids, in which cholesterol esters (ChE) have the highest PUFA share (94 %), followed by polar membrane lipids (glycolipids and phospholipids), with phosphatidylethanolamines (PE) up to 67 %, phosphatidylglycerols (PG) up to 47 %, and monogalactosyldiacylglycerols (MGDG) up to 47 % PUFA content. This highlights the high percentage of PUFA in the structural parts of microalgae and the importance of these lipid classes as a reservoir for PUFA. Finally, we also compared a classical Folch extraction method with environmentally friendly ultrasound-assisted extraction approaches and enzymatic pre-treatments to investigate the lipid composition and enrichment of valuable lipid classes. Thus, this extensive analysis of the (glyco-)lipidome of Microchloropsis gaditana provides valuable insights into the existing knowledge about this microalgae species, enhancing our understanding of the complex lipid composition and opening up new opportunities for potential applications in the biotechnology and food industry.

Hydrothermal liquefaction of Chlamydomonas nivalis and Nannochloropsis gaditana microalgae under different operating conditions over copper-exchanged zeolites

In this study, two different green microalgae, Chlamydomonas nivalis (C. nivalis) and Nannochloropsis gaditana (N. gaditana), were cultivated in open ponds and the harvested wet biomass was converted to bio-crude by hydrothermal liquefaction (HTL) with/without catalyst. Catalytic HTL experiments were performed by using copper-exchanged zeolites including Cu-MOR, Cu-ZSM-5, and Cu-SSZ13, synthesized by recently developed supercritical ion exchange method using scCO2. The composition of all bio-crudes was analyzed by elemental analysis and GC/MS. First, the effects of different operating conditions on the yields of the products and the bio-crude composition were determined for non-catalytic process. Temperature, duration, and water/algae biomass ratio in the feed were the process parameters investigated in the ranges of 250–350 ºC, 10–60 min, and 5–20 wt%, respectively. For C. nivalis, 300 ºC, 60 min, and water/algae ratio of 4 were the optimum conditions which led to maximum bio-crude yield of 18.8 wt%, while 300 ºC, 30 min, and water/algae ratio of 9 were the optimum ones for N. gaditana at which the maximum bio-crude yield of 34.0 wt% was observed. Bio-crude yield of N. gaditana was improved using Cu-MOR, while using catalysts for the case of C. nivalis resulted in more gasification with no positive effect on bio-crude yield. Moreover, elemental analysis showed that the fraction of nitrogen and oxygen in biocrude decreased in catalytic HTL runs, in line with the GC/MS results showing that the concentration of hydrocarbons and cyclic compounds increased in the presence of catalysts accompanied by a decrease in concentration of nitrogenous compounds.

Influence of desalination concentrate medium on microalgal metabolism, biomass production and biochemical composition

AbstractReverse osmosis is currently the most promising method for addressing freshwater scarcity in numerous nations, enabling the production of drinkable water for human consumption. This process, however, generates a byproduct stream, known as desalination concentrate (DC), that is enriched with high concentrations of salts such as Na+ and Cl−, moderate levels of SO42−, Mg2+, Ca2+ and K+ and trace levels of Si, Fe3+, NO3− and PO43−, which can be suitable and valuable for microalgal metabolism and growth. Salt concentration in DC can significantly influence microalgal growth via effects through osmotic shock, salt stress and cellular ionic ratios. Under certain conditions, these salinity changes can have a positive impact on microalgal metabolism, such as the synthesis of lipophilic compounds that include lipids, fatty acids and carotenoids. This mini‐review aims to provide up‐to‐date information of recent studies conducted towards the use of DC as a potential substrate for microalgal cultivation as well as to summarize the response mechanism of microalgae when cultured in DC. Several laboratory‐based studies have examined the effect of different DC concentrations on the biochemical composition of microalgae grown either in photobioreactors or in raceway ponds. These studies have uncovered significant effects of DC on the synthesis of proteins, amino acids and phycocyanin in freshwater species like Chlorella vulgaris and Arthrospira platensis, where DC tends to hinder these processes. Conversely, experiments with halophilic Dunaliella salina and marine Nannochloropsis gaditana have demonstrated that increasing DC concentration can positively influence the production of β‐carotene, lipids and specific saturated fatty acids (C16:0 and C18:0), suggesting that these species can adapt to a broader range of DC salinities. Cultivating salinity‐tolerant microalgae in DC would greatly reduce the production cost of algal‐based products, offering a promising approach to enhance the profitability of desalination and microalgal industries. © 2023 Society of Chemical Industry (SCI).

Study of the Effect of Water Content in Deep Eutectic Phases on the Extraction of Fatty Acids from Microalgae Biomass

Microalgae, as some of the oldest life forms on Earth, are of significant interest to industry and in terms of environmental policies, due to their ability to perform photosynthesis and consume atmospheric carbon dioxide. Moreover, they contain a wide variety of value-added compounds such as amino acids and proteins, carbohydrates, and fatty acids, which can be exploited in multiple fields like medicine, cosmetics, nutritional supplements, and for the production of biodiesel. In this article, Nannochloropsis gaditana, a type of microalgae that inhabits both fresh and salt water, is studied for fatty acid recovery using deep eutectic solvents (DES). This microalgae species is a natural source of eicosapentaenoic acid (EPA), an omega-3 compound that is commonly used in the nutritional industry. There are numerous extraction techniques and pretreatments to obtain these compounds. In this work, DES are studied as extractive agents due to their advantages as neoteric solvents. Specifically, this work focuses on an assessment of the effect of the composition of DES on the extraction yield of fatty acids from microalgae. Several DES compositions based on choline chloride, ethylene glycol, and fructose are studied to analyze the influence of water content in these phases. The results show that water content significantly influences recovery yields. The DES with higher extractive capacity were those based on choline chloride, ethylene glycol, and water at a molar ratio of 1:2:2. This composition offered 48.7% of the yield obtained with a conventional solvent like methanol for the recovery of EPA (11.2 mg/g microalgae). Furthermore, the choline chloride-fructose-based DES shows the capability of selective extractions of fatty acids with low carbon content—choline chloride:fructose:water (molar ratio 2:1:2) can extract 0.14 mg of decanoic acid/g of microalgae, indicating that this DES composition can recover 35.7% more decanoic acid in comparison to methanol.

Transparent antibiofouling coating to improve the efficiency of Nannochloropsis gaditana and Chlorella sorokiniana culture photobioreactors at the pilot-plant scale

The implementation of industrial-scale facilities for microalgae cultivation is limited due to the high operation costs. One of the main problems in obtaining an efficient and long-lasting microalgae culture system is biofouling. The particular issue when developing antibiofouling surfaces for microalgae cultures is that the material must be transparent. The main purpose of this work was to evaluate the antibiofouling efficiency of a non-toxic polydimethylsiloxane-based coating prepared with polyethylene glycol-based copolymer on different photobioreactors at the pilot-plant scale. The antifouling properties result from the development of a fouling-release coating utilizing hydrogel technology. Nannochloropsis gaditana and Chlorella sorokiniana were cultured outdoors for 3 months over the summer, when biofouling formation is at its highest due to environmental conditions, to test the coating's antibiofouling efficiency. Although biofouling was not completely prevented in either photobioreactor, the coating significantly reduced cell adhesion compared to the polydimethylsiloxane control (70% less adhesion). Therefore, this coating was shown to be a good alternative for constructing efficient closed-photobioreactors at the pilot-plant scale, at least for cultures lasting 3 months.

Spatio-temporal techno-economic assessment of the algae-based supply chain: A proof-of-concept for North-West Europe

The growing world population is in need for new sustainable resources for healthy food, animal feed and chemicals. Algae produce a variety of compounds via conversion of CO2, nutrients, and light, and offer potential as renewable feedstock. However, producing microalgae is costly. Therefore, new economically viable supply chains must be developed. A variety of techno-economic assessments (TEA) has been performed to gain insight in the economic feasibility of algae production systems and refineries. While a TEA provides insights relevant to the technical and economic feasibility of a process, geographical conditions must be considered since the regional characteristics influence process feasibility and supply chain design.This paper presents a spatio-temporal TEA by combining a dynamic TEA model and a supply chain design optimisation model, MooV. The dynamic TEA outlines the conditions of the processes to reach a techno-economic feasible case as well as mass balances and OPEX and CAPEX of the different potential processes in the chain. MooV combines these parameters with geographic specific parameters such as the locations of activities and the characteristics of the transport network to define the optimal supply chain configuration (e.g., location and process type and capacity) based on minimal cost.The approach is demonstrated by year-round cultivation of Nannochloropsis gaditana in a horizontal tubular photobioreactor in 3 regions in North-West Europe. The analysis indicates that the cost per kg DM algae output can vary considerably (±40 %) depending on the region and the set-up of the supply chain. Including geographic characteristics as well as comparing different supply chain design options are essential to come to a viable business case. The approach can also be applied to different algae strains, different regions and different process options.

Effect on Muscle Cellularity of Diet Supplementation with Nannochloropsis gaditana Microalgae in the Final Fattening Phase of Gilthead Seabream Culture up to Commercial Size

Previous studies have shown that Nannochloropsis gaditana can partially replace fishmeal in the diet of gilthead seabream, Sparus aurata. However, its effect on muscle growth is hardly known. This experiment was carried out with gilthead seabream adults that were fed with N. gaditana at two inclusion levels (2.5 or 5%) either raw (R2.5 and R5 groups) or cellulose-hydrolyzed (H2.5 and H5 groups) for 45 days in the final fattening phase. The body length and body weight were measured in all fish at the beginning and end of the experiment. Also, the white muscle transverse area (WM), size, number and fibrillar density of the white fibers were measured in 9 fish group−1. After 45 days, the body parameters and the WM did not show significant differences among the groups. However, muscle cellularity did show significant differences, such that the hypertrophy values were higher in the H2.5 and H5 than in the R2.5 and R5 groups. On the contrary, R2.5 and R5 showed the highest fibrillar density and hyperplasia values, which are often positively correlated with the fillet firmness and therefore could improve the final quality of the fish. No significant differences attributable to the inclusion levels of N. gaditana were observed.