Fucoxanthin as a major carotenoid in Isochrysis aff. galbana: Characterization of extraction for commercial application

Production of Fucoxanthin from Microalgae Isochrysis galbana of Djibouti: Optimization, Correlation with Antioxidant Potential, and Bioinformatics Approaches

Fucoxanthin, a carotenoid with remarkable antioxidant properties, has considerable potential for high-value biotechnological applications in the pharmaceutical, nutraceutical, and cosmeceutical fields. However, conventional extraction methods of this molecule from microalgae are limited in terms of cost-effectiveness. This study focused on optimizing biomass and fucoxanthin production from Isochrysis galbana, isolated from the coast of Tadjoura (Djibouti), by testing various culture media. The antioxidant potential of the cultures was evaluated based on the concentrations of fucoxanthin, carotenoids, and total phenols. Different nutrient formulations were tested to determine the optimal combination for a maximum biomass yield. Using the statistical methodology of principal component analysis, Walne and Guillard F/2 media were identified as the most promising, reaching a maximum fucoxanthin yield of 7.8 mg/g. Multiple regression models showed a strong correlation between antioxidant activity and the concentration of fucoxanthin produced. A thorough study of the optimization of I. galbana growth conditions, using a design of experiments, revealed that air flow rate and CO2 flow rate were the most influential factors on fucoxanthin production, reaching a value of 13.4 mg/g. Finally, to validate the antioxidant potential of fucoxanthin, an in silico analysis based on molecular docking was performed, showing that fucoxanthin interacts with antioxidant proteins (3FS1, 3L2C, and 8BBK). This research not only confirmed the positive results of I. galbana cultivation in terms of antioxidant activity, but also provided essential information for the optimization of fucoxanthin production, opening up promising prospects for industrial applications and future research.

A comprehensive review on the heterotrophic production of bioactive compounds by microalgae

Bioactive compounds derived from microalgae have garnered considerable attention as valuable resources for drugs, functional foods, and cosmetics. Among these compounds, photosynthetic pigments and polyunsaturated fatty acids (PUFAs) have gained increasing interest due to their numerous beneficial properties, including anti-oxidant, anti-viral, anti-bacterial, anti-fungal, anti-inflammatory, and anti-tumor effects. Several microalgae species have been identified as rich sources of bioactive compounds, including the Chlorophyceae Dunaliella and Haematococcus, the Bacillariophyta Phaeodactylum and Nitzschia, and the dinoflagellate Crypthecodinium cohnii. However, most of the reported microalgae species primarily grow through autotrophic mechanisms, resulting in low yields and high production costs of bioactive compounds. Consequently, the utilization of heterotrophic microalgae, such as Chromochloris zofingiensis and Nitzschia laevis, has shown significant advantages in the production of astaxanthin and eicosapentaenoic acid (EPA), respectively. These heterotrophic microalgae exhibit superior capabilities in synthesizing target compounds. This comprehensive review provides a thorough examination of the heterotrophic production of bioactive compounds by microalgae. It covers key aspects, including the metabolic pathways involved, the impact of cultivation conditions, and the practical applications of these compounds. The review discusses how heterotrophic cultivation strategies can be optimized to enhance bioactive compound yields, shedding light on the potential of microalgae as a valuable resource for high-value product development.

Bridging artificial intelligence and fucoxanthin for the recovery and quantification from microalgae

Fucoxanthin is a carotenoid that possesses various beneficial medicinal properties for human well-being. However, the current extraction technologies and quantification techniques are still lacking in terms of cost validation, high energy consumption, long extraction time, and low yield production. To date, artificial intelligence (AI) models can assist and improvise the bottleneck of fucoxanthin extraction and quantification process by establishing new technologies and processes which involve big data, digitalization, and automation for efficiency fucoxanthin production. This review highlights the application of AI models such as artificial neural network (ANN) and adaptive neuro fuzzy inference system (ANFIS), capable of learning patterns and relationships from large datasets, capturing non-linearity, and predicting optimal conditions that significantly impact the fucoxanthin extraction yield. On top of that, combining metaheuristic algorithm such as genetic algorithm (GA) can further improve the parameter space and discovery of optimal conditions of ANN and ANFIS models, which results in high R2 accuracy ranging from 98.28% to 99.60% after optimization. Besides, AI models such as support vector machine (SVM), convolutional neural networks (CNNs), and ANN have been leveraged for the quantification of fucoxanthin, either computer vision based on color space of images or regression analysis based on statistical data. The findings are reliable when modeling for the concentration of pigments with high R2 accuracy ranging from 66.0% - 99.2%. This review paper has reviewed the feasibility and potential of AI for the extraction and quantification purposes, which can reduce the cost, accelerate the fucoxanthin yields, and development of fucoxanthin-based products.

Fucoxanthin, a Functional Food Ingredient: Challenges in Bioavailability

PURPOSE OF REVIEW

Fucoxanthin is an orange-red xanthophyll carotenoid found in brown seaweeds and known for its many bioactive properties. In recent years, the bioactive properties of fucoxanthin have been widely explored, making it a compound of immense interest for various health applications like anti-cancer, anti-tumour, anti-diabetic and anti-obesity properties. However, the poor bioavailability and instability of fucoxanthin in the gastrointestinal tract have major limitations. Encapsulation is a promising approach to overcome these challenges by enclosing fucoxanthin in a protective layer, such as liposomes or nano-particles. Encapsulation can improve the stability of fucoxanthin by protecting it from exposure to heat, pH, illumination, gastric acids and enzymes that can accelerate its degradation.

RECENT FINDINGS

Studies have shown that lipid-based encapsulation systems such as liposomes or nano-structured lipid carriers may solubilise fucoxanthin and enhance its bioavailability (from 25 to 61.2%). In addition, encapsulation can also improve the solubility of hydrophobic fucoxanthin, which is important for its absorption and bioavailability. This review highlights the challenges involved in the absorption of fucoxanthin in the living system, role of micro- and nano-encapsulation of fucoxanthin and their potential to enhance intestinal absorption.

Description and Characterization of the Odontella aurita OAOSH22, a Marine Diatom Rich in Eicosapentaenoic Acid and Fucoxanthin, Isolated from Osan Harbor, Korea

Third-generation biomass production utilizing microalgae exhibits sustainable and environmentally friendly attributes, along with significant potential as a source of physiologically active compounds. However, the process of screening and localizing strains that are capable of producing high-value-added substances necessitates a significant amount of effort. In the present study, we have successfully isolated the indigenous marine diatom Odontella aurita OAOSH22 from the east coast of Korea. Afterwards, comprehensive analysis was conducted on its morphological, molecular, and biochemical characteristics. In addition, a series of experiments was conducted to analyze the effects of various environmental factors that should be considered during cultivation, such as water temperature, salinity, irradiance, and nutrients (particularly nitrate, silicate, phosphate, and iron). The morphological characteristics of the isolate were observed using optical and electron microscopes, and it exhibited features typical of O. aurita. Additionally, the molecular phylogenetic inference derived from the sequence of the small-subunit 18S rDNA confirmed the classification of the microalgal strain as O. aurita. This isolate has been confirmed to contain 7.1 mg g-1 dry cell weight (DCW) of fucoxanthin, a powerful antioxidant substance. In addition, this isolate contains 11.1 mg g-1 DCW of eicosapentaenoic acid (EPA), which is one of the nutritionally essential polyunsaturated fatty acids. Therefore, this indigenous isolate exhibits significant potential as a valuable source of bioactive substances for various bio-industrial applications.

Valuable pigments from microalgae: phycobiliproteins, primary carotenoids, and fucoxanthin

Phycobiliproteins, carotenoids and fucoxanthin are photosynthetic pigments extracted from microalgae and cyanobacteria with great potential biotechnological applications, as healthy food colorants and cosmetics. Phycocyanin possesses a brilliant blue color, with fluorescent properties making it useful as a reagent for immunological essays. The most important source of phycocyanin is the cyanobacterium Arthrospira platensis, however, recently, the Rhodophyta Galdieria sulphuraria has also been identified as such. The main obstacle to the commercialization of phycocyanin is represented by its chemical instability, strongly reducing its shelf-life. Moreover, the high level of purity needed for pharmaceutical applications requires several steps which increase both the production time and cost. Microalgae (Chlorella, Dunaliella, Nannochloropsis, Scenedesmus) produce several light harvesting carotenoids, and are able to manage with oxidative stress, due to their free radical scavenging properties, which makes them suitable for use as source of natural antioxidants. Many studies focused on the selection of the most promising strains producing valuable carotenoids and on their extraction and purification. Among carotenoids produced by marine microalgae, fucoxanthin is the most abundant, representing more than 10% of total carotenoids. Despite the abundance and diversity of fucoxanthin producing microalgae only a few species have been studied for commercial production, the most relevant being Phaeodactylum tricornutum. Due to its antioxidant activity, fucoxanthin can bring various potential benefits to the prevention and treatment of lifestyle-related diseases. In this review, we update the main results achieved in the production, extraction, purification, and commercialization of these important pigments, motivating the cultivation of microalgae as a source of natural pigments.

Roles of Marine Macroalgae or Seaweeds and Their Bioactive Compounds in Combating Overweight, Obesity and Diabetes: A Comprehensive Review

Obesity and diabetes are matters of serious concern in the health sector due to their rapid increase in prevalence over the last three decades. Obesity is a severe metabolic problem that results in energy imbalance that is persistent over a long period of time, and it is characterized by insulin resistance, suggesting a strong association with type 2 diabetes (T2D). The available therapies for these diseases have side effects and some still need to be approved by the Food and Drug Administration (FDA), and they are expensive for underdeveloped countries. Hence, the need for natural anti-obesity and anti-diabetic drugs has increased in recent years due to their lower costs and having virtually no or negligible side effects. This review thoroughly examined the anti-obesity and anti-diabetic effects of various marine macroalgae or seaweeds and their bioactive compounds in different experimental settings. According to the findings of this review, seaweeds and their bioactive compounds have been shown to have strong potential to alleviate obesity and diabetes in both in vitro and in vivo or animal-model studies. However, the number of clinical trials in this regard is limited. Hence, further studies investigating the effects of marine algal extracts and their bioactive compounds in clinical settings are required for developing anti-obesity and anti-diabetic medicines with better efficacy but lower or no side effects.

Combined analysis of chromatin accessibility and gene expression profiles provide insight into Fucoxanthin biosynthesis in Isochrysis galbana under green light

Isochrysis galbana, as a potential accumulator of fucoxanthin, has become a valuable material to develop functional foods for humans. Our previous research revealed that green light effectively promotes the accumulation of fucoxanthin in I. galbana, but there is little research on chromatin accessibility in the process of transcriptional regulation. This study was conducted to reveal the mechanism of fucoxanthin biosynthesis in I. galbana under green light by analyzing promoter accessibility and gene expression profiles. Differentially accessible chromatin regions (DARs)-associated genes were enriched in carotenoid biosynthesis and photosynthesis-antenna protein formation, including IgLHCA1, IgLHCA4, IgPDS, IgZ-ISO, IglcyB, IgZEP, and IgVDE. The motifs for the MYB family were also identified as candidates controlling metabolic regulation responses to green light culture of I. galbana, including IgMYB1, IgMYB2, IgMYB33, IgMYB42, IgMYB98, IgMYB118, and IgMYB119. The results of differential expression analysis and WGCNA showed that several genes or transcription factors (TFs) related to carotenoid metabolism and photosynthesis exhibited a higher expression level and were significantly upregulated in A-G5d compared with A-0d and A-W5d, including IgMYB98, IgLHCA1, IgLHCX2, IgLHCB4, and IgLHCB5. This suggests that upregulation of these genes by green light may be the key factor leading to fucoxanthin accumulation by regulating the photosynthesis-antenna protein pathway. An integrated analysis of ATAC-seq and RNA-seq showed that 3 (IgphoA, IgPKN1, IgOTC) of 34 DARs-associated genes displayed obvious changes in their chromatin regions in ATAC-seq data, suggesting that these genes specific for green light may play a key role in fucoxanthin biosynthesis in I. galbana through a complex regulatory network of multiple metabolic pathways interacting with each other. These findings will facilitate in-depth understanding the molecular regulation mechanisms of fucoxanthin in I. galbana and its role in response to green light regulation, providing technical support for the construction of high fucoxanthin content strains.

Microalgae-Derived Pigments for the Food Industry

In the food industry, manufacturers and customers have paid more attention to natural pigments instead of the synthetic counterparts for their excellent coloring ability and healthy properties. Microalgae are proven as one of the major photosynthesizers of naturally derived commercial pigments, gaining higher value in the global food pigment market. Microalgae-derived pigments, especially chlorophylls, carotenoids and phycobiliproteins, have unique colors and molecular structures, respectively, and show different physiological activities and health effects in the human body. This review provides recent updates on characteristics, application fields, stability in production and extraction processes of chlorophylls, carotenoids and phycobiliproteins to standardize and analyze their commercial production from microalgae. Potential food commodities for the pigment as eco-friendly colorants, nutraceuticals, and antioxidants are summarized for the target products. Then, recent cultivation strategies, metabolic and genomic designs are presented for high pigment productivity. Technical bottlenecks of downstream processing are discussed for improved stability and bioaccessibility during production. The production strategies of microalgal pigments have been exploited to varying degrees, with some already being applied at scale while others remain at the laboratory level. Finally, some factors affecting their global market value and future prospects are proposed. The microalgae-derived pigments have great potential in the food industry due to their high nutritional value and competitive production cost.

Immunomodulatory effects of Isochrysis galbana incorporated diet on Oreochromis sp. (red hybrid tilapia) via Sera-1H NMR metabolomics study

Tilapia is one of the most common fish species that is intensively produced all over the world. However, significant measures at improving aquaculture health must be taken since disease outbreaks are often encountered in the rapidly developing aquaculture industry. Therefore, the objective of the study was designed to evaluate the metabolite changes in tilapia' sera through ¹H NMR metabolomics in identifying the potential biomarkers responsible for immunomodulatory effect by the indigenous species of Malaysian microalgae Isochrysis galbana (IG). The results showed that IG-incorporated diet mainly at 5.0% has improved the immune response of innate immunity as observed in serum bactericidal activity (SBA) and serum lysozyme activity (SLA). The orthogonal partial least squares (OPLS) analysis indicated 5 important metabolites significantly upregulated namely as ethanol, lipoprotein, lipid, α-glucose and unsaturated fatty acid (UFA) in the 5.0% IG-incorporated diet compared to control. In conclusion, this study had successfully determined IG in improving aquaculture health through its potential use as an immune modulator. This work also demonstrated the effective use of metabolomics approach in the development of alternative nutritious diet from microalgae species to boost fish health in fulfilling the aquaculture's long-term goals.

Bioactive Compounds from Red Microalgae with Therapeutic and Nutritional Value

Red microalgae represent a natural reservoir of beneficial substances with applications in different industrial sectors. They are rich in natural biomolecules known for their antihypertensive, antioxidant, antimicrobial, antiviral, anti-inflammatory, antitumor, and anticoagulant activities. Many red microalgae are a source of vitamins, minerals, photochemicals, polyunsaturated fatty acids, and a wide spectrum of polysaccharides. The content of their valuable compounds and their activities have turned red microalgae into cellular factories of special interest in food, nutraceutical, and pharmaceutical industries. Like all microalgae, the red ones are superior to traditional crops for the aims of biotechnology as they are renewable sources widely available in great quantities and are easy to culture. Moreover, some of the most studied red microalgae are generally recognized as safe. This review summarizes the valuable biochemicals from red microalgae and highlights their health and nutritional benefits.

Comparative RNA-Seq analysis unravels molecular mechanisms regulating therapeutic properties in the grains of traditional rice Kavuni

Developing rice varieties with enhanced levels of functional bioactives is an important intervention for achieving food and nutritional security in Asia where rice is the staple food and Type II diabetes incidences are higher. The present study was aimed at dissecting out the molecular events underlying the accumulation of bio active compounds in pigmented traditional rice Kavuni. Comparative transcriptome profiling in the developing grains of Kavuni and a white rice variety ASD 16 generated 37.7 and 29.8 million reads respectively. Statistical analysis identified a total of 9177 exhibiting significant differential expression (DEGs) between the grains of Kavuni and ASD 16. Pathway mapping of DEGs revealed the preferential up-regulation of genes involved in the biosynthesis of amylose and dietary fibres in Kavuni accounting for its low glycemic index (GI). Transcripts involved in the biosynthesis of carotenoids, flavonoids, anthocyanins, phenolic acids and phenylpropanoids were also found to be up-regulated in the grains of Kavuni. This study identified up-regulation of key transcripts involved in the accumulation of phenolic acids having potential for inhibiting major hydrolytic enzymes α-amylase and α-glucosidase and thus accounting for the slow digestibility leading to low GI. Overall, this study has identified molecular targets for the genetic manipulation of anti-diabetic and anti-oxidant traits in rice.

Fucoxanthin Production of Microalgae under Different Culture Factors: A Systematic Review

Fucoxanthin is one of the light-harvesting pigments in brown microalgae, which is increasingly gaining attention due to its numerous health-promoting properties. Currently, the production of microalgal fucoxanthin is not yet feasible from an economic perspective. However, the cultivation of microalgae at favourable conditions holds great potential to increase the viability of this fucoxanthin source. Hence, this study aimed to review the fucoxanthin production of microalgae under different conditions systematically. A literature search was performed using the Web of Science, Scopus and PubMed databases. A total of 188 articles were downloaded and 28 articles were selected for the current review by two independent authors. Microalgae appeared to be a more reliable fucoxanthin source compared to macroalgae. Overall, a consensus fucoxanthin production condition was obtained and proposed: light intensity ranging from 10 to 100 µmol/m²/s could achieve a higher fucoxanthin content. However, the optimal light condition in producing fucoxanthin is species-specific. The current review serves as an antecedent by offering insights into the fucoxanthin-producing microalgae response to different culture factors via a systematic analysis. With the current findings and recommendations, the feasibility of producing fucoxanthin commercially could be enhanced and possibly achieve practical and sustainable fucoxanthin production.

Synthesis and physicochemical characterization of rhamnolipid fabricated fucoxanthin loaded bovine serum albumin nanoparticles supported by simulation studies

BACKGROUND

Fucoxanthin is a hydrophobic carotenoid with many beneficial biological activities. However, due to low aqueous solubility their clinical efficacy is limited thus leading to poor oral bioavailability. To address this issue, we encapsulated fucoxanthin in rhamnolipid fabricated bovine serum albumin (BSA) loaded nanoparticles (LNPs) for improving solubility dependent bioavailability of fucoxanthin.

RESULTS

These synthesized LNPs were characterized by dynamic light scattering (DLS), ultraviolet (UV)-visible spectrophotometry, high-performance liquid chromatography (HPLC), Fourier-transform infrared (FTIR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC). Our results showed that LNPs were spherical in shape with particle size around 180 nm along with positive zeta potential. The encapsulation efficiency and loading efficiency calculated for LNPs were 69.66 ± 1.5% and 14 ± 0.2%, respectively. The antioxidant assay of LNPs indicate high radical scavenging activity compared to pure fucoxanthin. Besides this, our release studies indicates that drug release occur from the matrix of nanocarrier system through diffusion based on concentration. Thus, these findings indicate successful encapsulation of fucoxanthin, with improved solubility thereby leading to increased bioavailability. This nano formulation is derived from components which are FDA approved that could be exploited for encapsulating other vital nutraceutical molecules.

CONCLUSION

Overall, our results showed successful synthesis of biodegradable nanocarrier for delivering fucoxanthin supported by molecular docking, molecular dynamics simulation and thermodynamics of free binding energy studies. © 2022 Society of Chemical Industry.

Multi-omics analyses provide insight into the biosynthesis pathways of fucoxanthin in Isochrysis galbana

Isochrysis galbana is considered an ideal bait for functional foods and nutraceuticals of humans because of its high fucoxanthin (Fx) content. However, multi-omics analysis of the regulation networks for Fx biosynthesis in I. galbana has not been reported. In this study, we report a high-quality genome sequence of I. galbana LG007, which has a 92.73 Mb genome size, with a contig N50 of 6.99 Mb and 14,900 protein-coding genes. Phylogenomic inferences confirmed the monophyly of Haptophyta, with I. galbana sister to Emiliania huxleyi and Chrysochromulina tobinii. Evolutionary analysis revealed an estimated divergence time between I. galbana and E. huxleyi of ∼ 133 million years ago (Mya). Gene family analysis indicated that lipid metabolism-related genes exhibited significant expansion, including IgPLMT, IgOAR1, and IgDEGS1. Metabolome analysis showed that the content of carotenoids in I. galbana cultured under green light for 7 days was higher than that of white light, and β-carotene was the main carotenoid, accounting for 79.09% of the total carotenoids. Comprehensive analysis of multi-omics analysis revealed that β-carotene, antheraxanthin, zeaxanthin, and Fx content was increased by green light induction, which was significantly correlated with the expression of IgMYB98, IgZDS, IgPDS, IgLHCX2, IgZEP, IgLCYb, and IgNSY. These findings contribute to understanding Fx biosynthesis and its regulation, providing a valuable reference for food and pharmaceutical applications.

High-Purity Fucoxanthin Can Be Efficiently Prepared from Isochrysis zhangjiangensis by Ethanol-Based Green Method Coupled with Octadecylsilyl (ODS) Column Chromatography

The exploitation of new economically valuable microalgae as a sustainable source of minor high-value products can effectively promote the full utilization of microalgae. The efficient preparation of minor products from microalgae remains the challenge, owing to the coexistence of various components with a similar polarity in the microalgae biomass. In this study, a novel approach based on the sustainable-oriented strategy for fucoxanthin (FX) production was proposed, which consisted of four steps, including the culture of microalga, ethanol extraction, ODS column chromatography, and ethanol precipitation. The high-purity FX (around 95%) was efficiently obtained in a total recovery efficiency of 84.28 ± 2.56%. This study reveals that I. zhangjiangensis is a potentially promising feedstock for FX production and firstly provides a potentially eco-friendly method for the scale-up preparation of FX from the microalga I. zhangjiangensis.

Extraction of Fucoxanthin Isomers from the Edible Brown Seaweed Undaria pinnatifida Using Supercritical CO2: Effects of Extraction Conditions on Isomerization and Recovery of Fucoxanthin

Fucoxanthin, a characteristic carotenoid found in brown seaweeds, has been reported to exert beneficial biological activities, including antiobesity and anticancer activities Moreover, the Z-isomers of this compound potentially have greater bioavailability and biological activities than the naturally predominant all-E-isomer. Therefore, the consumption of Z-isomer-rich fucoxanthin through daily meals and dietary supplements may have beneficial effects. In this study, we aimed to investigate the effects of different extraction conditions on the Z-isomer ratio and recovery of fucoxanthin obtained from Undaria pinnatifida using supercritical CO2 (SC-CO2), particularly focusing on the high-temperature conditions that enhance thermal Z-isomerization. High-temperature SC-CO2 extraction at ≥ 120°C was found to enhance the thermal isomerization of fucoxanthin. For example, when the extraction was performed at 40, 80, 120, and 160°C and 30 MPa for 30 min with a co-solvent (ethanol), the total Z-isomer ratios were 11.7, 11.5, 18.7, and 26.5%, respectively. Furthermore, the high-temperature extraction significantly improved fucoxanthin recovery under high-pressure (≥ 30 MPa) conditions in the presence of the co-solvent. For example, when fucoxanthin was extracted at 40, 80, 120, and 160°C under the same conditions as above, the recoveries were 17.5, 20.6, 30.7, and 29.5%, respectively. Hence, the high-temperature SC-CO2 extraction of fucoxanthin from U. pinnatifida would not only enhance health benefits of fucoxanthin via the Z-isomerization but also improve the productivity. Moreover, the use of non-toxic CO2 and a low-toxicity organic solvent (ethanol) ensures that the final fucoxanthin product is safe for consumption. The Z-isomer-rich fucoxanthin obtained using this method is accordingly considered to have potential for use as a dietary supplement.

Fucoxanthin: A Promising Phytochemical on Diverse Pharmacological Targets

Fucoxanthin (FX) is a special carotenoid having an allenic bond in its structure. FX is extracted from a variety of algae and edible seaweeds. It has been proved to contain numerous health benefits and preventive effects against diseases like diabetes, obesity, liver cirrhosis, malignant cancer, etc. Thus, FX can be used as a potent source of both pharmacological and nutritional ingredient to prevent infectious diseases. In this review, we gathered the information regarding the current findings on antimicrobial, antioxidant, anti-inflammatory, skin protective, anti-obesity, antidiabetic, hepatoprotective, and other properties of FX including its bioavailability and stability characteristics. This review aims to assist further biochemical studies in order to develop further pharmaceutical assets and nutritional products in combination with FX and its various metabolites.

Rapid Purification of Fucoxanthin from Phaeodactylum tricornutum

Fucoxanthin is a natural marine xanthophyll and exhibits a broad range of biological activities. In the present study, a simple and efficient two-step method was used to purify fucoxanthin from the diatom, Phaeodactylum tricornutum. The crude pigment extract of fucoxanthin was separated by silica gel column chromatography (SGCC). Then, the fucoxanthin-rich fraction was purified using a hydrophile-lipophile balance (HLB) solid-phase extraction column. The identification and quantification of fucoxanthin were determined by high-performance liquid chromatography (HPLC) and electrospray ionization mass spectrometry (ESI-MS). This two-step method can obtain 92.03% pure fucoxanthin and a 76.67% recovery rate. In addition, ¹H and ¹³C NMR spectrums were adopted to confirm the identity of fucoxanthin. Finally, the purified fucoxanthin exhibited strong antioxidant properties in vitro with the effective concentration for 50% of maximal scavenging (EC50) of 1,1-Dihpenyl-2-picrylhydrazyl (DPPH) and 2,2'-Azinobis-(3-ethylbenzthiazoline-6-sulphonate) (ABTS) free radicals being 0.14 mg·mL^-1 and 0.05 mg·mL^-1, respectively.

Fucoxanthin from Algae to Human, an Extraordinary Bioresource: Insights and Advances in up and Downstream Processes

Fucoxanthin is a brown-colored pigment from algae, with great potential as a bioactive molecule due to its numerous properties. This review aims to present current knowledge on this high added-value pigment. An accurate analysis of the biological function of fucoxanthin explains its wide photon absorption capacities in golden-brown algae. The specific chemical structure of this pigment also leads to many functional activities in human health. They are outlined in this work and are supported by the latest studies in the literature. The scientific and industrial interest in fucoxanthin is correlated with great improvements in the development of algae cultures and downstream processes. The best fucoxanthin producing algae and their associated culture parameters are described. The light intensity is a major influencing factor, as it has to enable both a high biomass growth and a high fucoxanthin content. This review also insists on the most eco-friendly and innovative extraction methods and their perspective within the next years. The use of bio-based solvents, aqueous two-phase systems and the centrifugal partition chromatography are the most promising processes. The analysis of the global market and multiple applications of fucoxanthin revealed that Asian companies are major actors in the market with macroalgae. In addition, fucoxanthin from microalgae are currently produced in Israel and France, and are mostly authorized in the USA.

Production of fucoxanthin from the microalga Tisochrysis lutea in the bubble column photobioreactor applying mass transfer coefficient

Fucoxanthin is one of the most vital pigments during photosynthesis and is extracted from golden-brown micro-algae such as Tisochrysis lutea. The present study investigates the constant volumetric mass transfer coefficient (k_La), for the first time as the scale-up strategy to change the scale from 500 mL to 2-L cultivation flasks, and 5-L bubble column photobioreactor for fucoxanthin production in T. lutea. The cell density and fucoxanthin content were improved because of through fine aeration, nutrients, and light availability by successful laboratory scale up. Fucoxanthin productivity obtained 21.20, 22.99, and 24.96 mg L^-1day^-1 for 500 mL, 2-L bottle, and 5-L bubble column photobioreactor, respectively. In addition, the biomass productivity enhanced from 267.5 to 275 and 284 mg L^-1day^-1 in three mentioned scales, respectively. Eventually, the scale up process for the production of fucoxanthin was succeeded from 500 mL bottle to 5-L photobioreactor using constant (k_La) under laboratory conditions.

Perspectives of fluorescence spectroscopy for online monitoring in microalgae industry

Microalgae industrial production is viewed as a solution for alternative production of nutraceuticals, cosmetics, biofertilizers, and biopolymers. Throughout the years, several technological advances have been implemented, increasing the competitiveness of microalgae industry. However, online monitoring and real-time process control of a microalgae production factory still require further development. In this mini-review, non-destructive tools for online monitoring of cellular agriculture applications are described. Still, the focus is on the use of fluorescence spectroscopy to monitor several parameters (cell concentration, pigments, and lipids) in the microalgae industry. The development presented makes it the most promising solution for monitoring up-and downstream processes, different biological parameters simultaneously, and different microalgae species. The improvements needed for industrial application of this technology are also discussed.

Supercritical Fluid Extraction of Fucoxanthin from the Diatom Phaeodactylum tricornutum and Biogas Production through Anaerobic Digestion

Phaeodactylum tricornutum is the marine diatom best known for high-value compounds that are useful in aquaculture and food area. In this study, fucoxanthin was first extracted from the diatom using supercritical fluid extraction (SFE) and then using the extracted diatom-like substrate to produce bioenergy through anaerobic digestion (AD) processes. Factors such as temperature (30 °C and 50 °C), pressure (20, 30, and 40 MPa), and ethanol (co-solvent concentration from 10% to 50% v/v) were optimized for improving the yield, purity, and recovery of fucoxanthin extracted using SFE. The highest yield (24.41% w/w) was obtained at 30 MPa, 30 °C, and 30% ethanol but the highest fucoxanthin purity and recovery (85.03mg/g extract and 66.60% w/w, respectively) were obtained at 30 MPa, 30 °C, and 40%ethanol. Furthermore, ethanol as a factor had the most significant effect on the overall process of SFE. Subsequently, P.tricornutum biomass and SFE-extracted diatom were used as substrates for biogas production through AD. The effect of fucoxanthin was studied on the yield of AD, which resulted in 77.15 ± 3.85 LSTP CH4/kg volatile solids (VS) and 56.66 ± 1.90 LSTP CH4/kg VS for the whole diatom and the extracted P.tricornutum, respectively. Therefore, P.tricornutuman can be considered a potential source of fucoxanthin and methane and both productions will contribute to the sustainability of the algae-biorefinery processes.

Photosensitization of fucoxanthin-graphene complexes: A computational approach

Photosensitization of fucoxanthin-graphene (FX-GR) complexes were investigated in this work for detecting their roles of irradiating energy absorptions. To this aim, density functional theory (DFT computational approach as employed to obtain the optimized structures and their corresponding molecular orbital features. Both of original linear models of FX and its broken models, LFX and RFX, were investigated for attaching to a brigading GR molecular model. In this regard, the models were optimized to obtain the minimized energy configurations, in which for double-attachment of FG to the GR coroner atoms, Cis and Trans configurations were obtained for the FX-GR complex models. Based on the obtained achievements of molecular orbitals photosensitization features, the models were varied by the absorbed wavelengths making them suitable for various applications. In this regard, both of shorter and longer irradiated wavelengths were applicable for the purpose.

Carotenoid Production from Microalgae: Biosynthesis, Salinity Responses and Novel Biotechnologies

Microalgae are excellent biological factories for high-value products and contain biofunctional carotenoids. Carotenoids are a group of natural pigments with high value in social production and human health. They have been widely used in food additives, pharmaceutics and cosmetics. Astaxanthin, β-carotene and lutein are currently the three carotenoids with the largest market share. Meanwhile, other less studied pigments, such as fucoxanthin and zeaxanthin, also exist in microalgae and have great biofunctional potentials. Since carotenoid accumulation is related to environments and cultivation of microalgae in seawater is a difficult biotechnological problem, the contributions of salt stress on carotenoid accumulation in microalgae need to be revealed for large-scale production. This review comprehensively summarizes the carotenoid biosynthesis and salinity responses of microalgae. Applications of salt stress to induce carotenoid accumulation, potentials of the Internet of Things in microalgae cultivation and future aspects for seawater cultivation are also discussed. As the global market share of carotenoids is still ascending, large-scale, economical and intelligent biotechnologies for carotenoid production play vital roles in the future microalgal economy.

Microalgal Systems for Wastewater Treatment: Technological Trends and Challenges towards Waste Recovery

Wastewater (WW) treatment using microalgae has become a growing trend due the economic and environmental benefits of the process. As microalgae need CO2, nitrogen, and phosphorus to grow, they remove these potential pollutants from wastewaters, making them able to replace energetically expensive treatment steps in conventional WW treatment. Unlike traditional sludge, biomass can be used to produce biofuels, biofertilizers, high value chemicals, and even next-generation growth media for “organically” grown microalgal biomass targeting zero-waste policies and contributing to a more sustainable circular bioeconomy. The main challenge in this technology is the techno-economic feasibility of the system. Alternatives such as the isolation of novel strains, the use of native consortia, and the design of new bioreactors have been studied to overcome this and aid the scale-up of microalgal systems. This review focuses on the treatment of urban, industrial, and agricultural wastewaters by microalgae and their ability to not only remove, but also promote the reuse, of those pollutants. Opportunities and future prospects are discussed, including the upgrading of the produced biomass into valuable compounds, mainly biofuels.

Microalgae Xanthophylls: From Biosynthesis Pathway and Production Techniques to Encapsulation Development

In the last 20 years, xanthophylls from microalgae have gained increased scientific and industrial interests. This review highlights the essential issues that concern this class of high value compounds. Firstly, their chemical diversity as the producer microorganisms was detailed. Then, the use of conventional and innovative extraction techniques was discussed. Upgraded knowledge on the biosynthetic pathway of the main xanthophylls produced by photosynthetic microorganisms was reviewed in depth, providing new insightful ideas, clarifying the function of these active biomolecules. In addition, the recent advances in encapsulation techniques of astaxanthin and fucoxanthin, such as spray and freeze drying, gelation, emulsification and coacervation were updated. Providing information about these topics and their applications and advances could be a help to students and young researchers who are interested in chemical and metabolic engineering, chemistry and natural products communities to approach the complex thematic of xanthophylls.

A review on the progress, challenges and prospects in commercializing microalgal fucoxanthin

Fucoxanthin, the most abundant but nearly untapped carotenoid resource, is in the spotlight in the last decade from various perspectives due to a wide range of bioactivities and healthy benefits. The exploitation of fucoxanthin for nutraceutical and pharmaceutical purposes encompasses enormous scientific and economic potentials. Traditional production of fucoxanthin from brown algae (macroalgae) is constrained by limited yield and prohibitively high cost. Microalgae, as the most diverse photoautotrophs, hold the promises as sustainable sources and ideal cell factories for commercial fucoxanthin production, owing to their rich fucoxanthin content and excellent biomass productivity. In this work, the recent progress in upstream (microalgae selection, optimization of culture conditions, trophic modes, cultivation strategies and biosynthesis pathway) as well as downstream processes (extraction) of fucoxanthin production has been comprehensively and critically reviewed. The major bottlenecks, such as screening of fucoxanthin-producers, conflict between biomass and fucoxanthin accumulation under high light condition, unclear steps in biosynthesis pathway and limited evaluation of outdoor scale-up cultivation and extraction, have been pinpointed. Most importantly, the applications of emerging and conventional techniques facilitating commercialization of microalgal fucoxanthin are highlighted. The reviewed and evaluated include breeding and high-throughput screening methods of elite strains; flashing light effect inducing concurrent biomass and fucoxanthin accumulation; fucoxanthin biosynthesis and the regulatory mechanisms associating with its accumulation elucidated with the development of genetic engineering and omics techniques; and photobioreactors, harvesting and extraction techniques suitable for scaling up fucoxanthin production. In conclusion, the prospects of microalgal fucoxanthin commercialization can be expected with the joint development of fundamental phycology and biotechnology.

Fucoxanthin and docosahexaenoic acid production by cold-adapted Tisochrysis lutea

Tisochrysis lutea is an important microalgal species for fucoxanthin and docosahexaenoic acid (DHA) production with an optimum cultivation temperature of approximately 30 °C. The aim of the present work was to develop a winter strain with high productivity at 15 °C. The response of the original strain to a decrease in temperature from 30 °C to 15 °C was investigated in continuous turbidostat experiments. This was followed by adaptation for >180 days at 15 °C and 2 rounds of sorting for cells with high chlorophyll fluorescence (top 5%) using fluorescence-activated cell sorting (FACS). For the original strain the productivity of biomass, fucoxanthin, and DHA decreased by 92 %, 98 % and 85 % respectively when decreasing the temperature from 30 °C to 15 °C. In the sorted cold-adapted 'winter strain', biomass, fucoxanthin, and DHA productivities were similar to those at 30 °C. In addition, the fucoxanthin concentration increased from 1.11 to 4.24 mg g^-1 dry weight and the polar lipid fraction in total fatty acids increased from 21 % to 55 %. The winter strain showed a robust and stable phenotype after one year of cultivation, expanding the outdoor fucoxanthin and lipid production seasons for this species.

Bioactive Compounds with Antiglioma Activity from Marine Species

The search for new chemical compounds with antitumor pharmacological activity is a necessary process for creating more effective drugs for each specific malignancy type. This review presents the outcomes of screening studies of natural compounds with high anti-glioma activity. Despite significant advances in cancer therapy, there are still some tumors currently considered completely incurable including brain gliomas. This review covers the main problems of the glioma chemotherapy including drug resistance, side effects of common anti-glioma drugs, and genetic diversity of brain tumors. The main emphasis is made on the characterization of natural compounds isolated from marine organisms because taxonomic diversity of organisms in seawaters significantly exceeds that of terrestrial species. Thus, we should expect greater chemical diversity of marine compounds and greater likelihood of finding effective molecules with antiglioma activity. The review covers at least 15 classes of organic compounds with their chemical formulas provided as well as semi-inhibitory concentrations, mechanisms of action, and pharmacokinetic profiles. In conclusion, the analysis of the taxonomic diversity of marine species containing bioactives with antiglioma activity is performed noting cytotoxicity indicators and to the tumor cells in comparison with similar indicators of antitumor agents approved for clinical use as antiglioblastoma chemotherapeutics.

Antidiabetic effect of fucoxanthin extracted from Sargassum angustifolium on streptozotocin-nicotinamide-induced type 2 diabetic mice

This work aimed to study the antidiabetic effect of encapsulated fucoxanthin with porous starch (PS) in streptozotocin and nicotinamide-induced type 2 diabetic mice. Fucoxanthin was extracted and purified from Sargassum angustifolium and encapsulated in porous starch (PS). Diabetic mice groups were gavaged daily with fucoxanthin (400 mg/kg), either free or encapsulated into PS, and metformin (50 mg/kg) for three weeks. The results exhibited that the fucoxanthin and fucoxanthin-loaded PS markedly prevented the weight gain in treated groups (p < .05). Moreover, both free and encapsulated fucoxanthin could decrease the fasting blood glucose and increase the plasma insulin level similar to metformin (p < .05). In addition, total cholesterol, triglyceride, and low-density lipoprotein were lower in the treated groups. These results confirm antiobesity effect of fucoxanthin by regulating lipid profile parameters. Moreover, the histopathology evaluation of pancreatic tissue in diabetic mice exhibited that oral administration of metformin and fucoxanthin caused regeneration of pancreatic beta cells. This study revealed the healthy effect of seaweed pigment as a suitable bioactive compound which can be used in functional foods for natural diabetes therapy.

Extraction of Pigments from Microalgae and Cyanobacteria—A Review on Current Methodologies

Pigments from microalgae and cyanobacteria have attracted great interest for industrial applications due to their bioactive potential and their natural product attributes. These pigments are usually sold as extracts, to overcome purification costs. The extraction of these compounds is based on cell disruption methodologies and chemical solubility of compounds. Different cell disruption methodologies have been used for pigment extraction, such as sonication, homogenization, high-pressure, CO2 supercritical fluid extraction, enzymatic extraction, and some other promising extraction methodologies such as ohmic heating and electric pulse technologies. The biggest constrain on pigment bioprocessing comes from the installation and operation costs; thus, fundamental and applied research are still needed to overcome such constrains and give the microalgae and cyanobacteria industry an opportunity in the world market. In this review, the main extraction methodologies will be discussed, taking into account the advantages and disadvantages for each kind of pigment, type of organism, cost, and final market.

Development of a Method for Fucoxanthin Production Using the Haptophyte Marine Microalga Pavlova sp. OPMS 30543

The natural pigment fucoxanthin has attracted global attention because of its superior antioxidant properties. The haptophyte marine microalgae Pavlova spp. are assumed to be promising industrial fucoxanthin producers as their lack of a cell wall could facilitate the commercialization of cultured cells as a whole food. This study screened promising Pavlova strains with high fucoxanthin content to develop an outdoor cultivation method for fucoxanthin production. Initial laboratory investigations of P. pinguis NBRC 102807, P. lutheri NBRC 102808, and Pavlova sp. OPMS 30543 identified OPMS 30543 as having the highest fucoxanthin content. The culture conditions were optimized for OPMS 30543. Compared with f/2 and Walne's media, the use of Daigo's IMK medium led to the highest biomass production and highest fucoxanthin accumulation. The presence of seawater elements in Daigo's IMK medium was necessary for the growth of OPMS 30543. OPMS 30543 was then cultured outdoors using acrylic pipe photobioreactors, a plastic bag, an open tank, and a raceway pond. Acrylic pipe photobioreactors with small diameters enabled the highest biomass production. Using an acrylic pipe photobioreactor with 60-mm diameter, a fucoxanthin productivity of 4.88 mg/L/day was achieved in outdoor cultivation. Thus, this study demonstrated the usefulness of Pavlova sp. OPMS 30543 for fucoxanthin production in outdoor cultivation.

Complementary Analytical Platforms of NMR Spectroscopy and LCMS Analysis in the Metabolite Profiling of Isochrysis galbana

This study was designed to profile the metabolites of Isochrysis galbana, an indigenous and less explored microalgae species. ¹H Nuclear Magnetic Resonance (NMR) spectroscopy and Liquid Chromatography-Mass Spectrometry (LCMS) were used to establish the metabolite profiles of five different extracts of this microalga, which are hexane (Hex), ethyl acetate (EtOAc), absolute ethanol (EtOH), EtOH:water 1:1 (AqE), and 100% water (Aq). Partial least square discriminant analysis (PLS–DA) of the generated profiles revealed that EtOAc and Aq extracts contain a diverse range of metabolites as compared to the other extracts with a total of twenty-one metabolites, comprising carotenoids, polyunsaturated fatty acids, and amino acids, that were putatively identified from the NMR spectra. Meanwhile, thirty-two metabolites were successfully annotated from the LCMS/MS data, ten of which (palmitic acid, oleic acid, α-linolenic acid, arachidic acid, cholesterol, DHA, DPA, fucoxanthin, astaxanthin, and pheophytin) were similar to those present in the NMR profile. Another eleven glycerophospholipids were discovered using MS/MS-based molecular network (MN) platform. The results of this study, besides providing a better understanding of I.galbana’s chemical make-up, will be of importance in exploring this species potential as a feed ingredient in the aquaculture industry.

Production and monitoring of biomass and fucoxanthin with brown microalgae under outdoor conditions

The effect of light on biomass and fucoxanthin (Fx) productivities was studied in two microalgae, Tisochrysis lutea and Phaeodactylum tricornutum. High and low biomass concentrations (1.1 and 0.4 g L-1 ) were tested in outdoor pilot-scale flat-panel photobioreactors at semi-continuous cultivation mode. Fluorescence spectroscopy coupled with chemometric modeling was used to develop prediction models for Fx content and for biomass concentration to be applied for both microalgae species. Prediction models showed high R2 for cell concentration (.93) and Fx content (.77). Biomass productivity was lower for high biomass concentration than low biomass concentration, for both microalgae (1.1 g L-1 : 75.66 and 98.14 mg L-1  d-1 , for T. lutea and P. tricornutum, respectively; 0.4 g L-1 : 129.9 and 158.47 mg L-1  d-1 , T. lutea and P. tricornutum). The same trend was observed in Fx productivity (1.1 g L-1 : 1.14 and 1.41 mg L-1 d-1 , T. lutea and P. tricornutum; 0.4 g L-1 : 2.09 and 1.73 mg L-1  d-1 , T. lutea and P. tricornutum). These results show that biomass and Fx productivities can be set by controlling biomass concentration under outdoor conditions and can be predicted using fluorescence spectroscopy. This monitoring tool opens new possibilities for online process control and optimization.

Light spectra as triggers for sorting improved strains of Tisochrysis lutea

It is known that microalgae respond to different light colors, but not at single-cell level. This work aimed to assess if different light colors could be used as triggers to sort over-producing cells. Six light spectra were used: red + green + blue (RGBL), blue (BL), red (RL), green (GL), blue + red (BRL) and blue + green (BGL). Fluorescence-activated cell sorting method was used to analyse single-cell fluorescence and sort cells. BGL and RGBL lead to the highest fucoxanthin production, while RL showed the lowest. Therefore, it was hypothesized that hyper-producing cells can be isolated efficiently under the adverse condition (RL). After exposure to all light colors for 14 days, the top 1% fucoxanthin producing cells were sorted. A sorted strain from RL showed higher (16-19%) growth rate and fucoxanthin productivity. This study showed how light spectra affected single-cell fucoxanthin and lipid contents and productivities. Also, it supplied an approach to sort for high-fucoxanthin or high-lipid cells.

High Productivity of Eicosapentaenoic Acid and Fucoxanthin by a Marine Diatom Chaetoceros gracilis in a Semi-Continuous Culture

Significantly high eicosapentaenoic acid (EPA) and fucoxanthin contents with high production rate were achieved in semi continuous culture of marine diatom. Effects of dilution rate on the production of biomass and high value biocompounds such as EPA and fucoxanthin were evaluated in semi-continuous cultures of Chaetoceros gracilis under high light condition. Cellular dry weight increased at lower dilution rate and higher light intensity conditions, and cell size strongly affected EPA and fucoxanthin contents. The smaller microalgae cells showed significantly higher (p < 0.05) value of 17.1 mg g-dw^-1 fucoxanthin and 41.5% EPA content per total fatty acid compared to those observed in the larger cells. Chaetoceros gracilis can accumulate relatively higher EPA and fucoxanthin than those reported previously. In addition, maintenance of small cell size by supplying sufficient nutrients and light energy can be the key for the increase production of valuable biocompounds in C. gracilis.

Advances in Studies on the Pharmacological Activities of Fucoxanthin

Fucoxanthin is a natural carotenoid derived mostly from many species of marine brown algae. It is characterized by small molecular weight, is chemically active, can be easily oxidized, and has diverse biological activities, thus protecting cell components from ROS. Fucoxanthin inhibits the proliferation of a variety of cancer cells, promotes weight loss, acts as an antioxidant and anti-inflammatory agent, interacts with the intestinal flora to protect intestinal health, prevents organ fibrosis, and exerts a multitude of other beneficial effects. Thus, fucoxanthin has a wide range of applications and broad prospects. This review focuses primarily on the latest progress in research on its pharmacological activity and underlying mechanisms.