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

A Review of Fucoxanthin Biomanufacturing from Phaeodactylum tricornutum

Microalgae, compared to macroalgae, exhibit advantages such as rapid growth rates, feasible large-scale cultivation, and high fucoxanthin content. Among these microalgae, Phaeodactylum tricornutum emerges as an optimal source for fucoxanthin production. This paper comprehensively reviews the research progress on fucoxanthin production using Phaeodactylum tricornutum from 2012 to 2022, offering detailed insights into various aspects, including strain selection, media optimization, nutritional requirements, lighting conditions, cell harvesting techniques, extraction solvents, extraction methodologies, as well as downstream separation and purification processes. Additionally, an economic analysis is performed to assess the costs of fucoxanthin production from Phaeodactylum tricornutum, with a comparative perspective to astaxanthin production from Haematococcus pluvialis. Lastly, this paper discusses the current challenges and future opportunities in this research field, serving as a valuable resource for researchers, producers, and industry managers seeking to further advance this domain.

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.

Optimizing cultivation strategies and scaling up for fucoxanthin production using Pavlova sp

The microalgal-based production of fucoxanthin has emerged as an imperative research endeavor due to its antioxidant, and anticancer properties. In this study, three brown marine microalgae, namely Skeletonema costatum, Chaetoceros gracilis, and Pavlova sp., were screened for fucoxanthin production. All strains displayed promising results, with Pavlova sp. exhibiting the highest fucoxanthin content (27.91 mg/g) and productivity (1.16 mg/L·day). Moreover, the influence of various cultivation parameters, such as culture media, salinity, sodium nitrate concentration, inoculum size, light intensity, and iron concentration, were investigated and optimized, resulting in a maximum fucoxanthin productivity of 7.89 mg/L·day. The investigation was further expanded to large-scale outdoor cultivation using 50 L tubular photobioreactors, illustrating the potential of Pavlova sp. and the cultivation process for future commercialization. The biomass and fucoxanthin productivity for the large-scale cultivation were 70.7 mg/L·day and 4.78 mg/L·day, respectively. Overall, the findings demonstrated considerable opportunities for fucoxanthin synthesis via microalgae cultivation and processing.

Understanding the Impact of Nitrogen Availability: A Limiting Factor for Enhancing Fucoxanthin Productivity in Microalgae Cultivation

This study aimed to investigate the regulation of fucoxanthin (FX) biosynthesis under various nitrogen conditions to optimize FX productivity in Phaeodactylum tricornutum. Apart from light, nitrogen availability significantly affects the FX production of microalgae; however, the underlying mechanism remains unclear. In batch culture, P. tricornutum was cultivated with normal (NN, 0.882 mM sodium nitrate), limited (LN, 0.22 mM), and high (HN, 8.82 mM) initial nitrogen concentrations in f/2 medium. Microalgal growth and photosynthetic pigment production were examined, and day 5 samples were subjected to fucoxanthin-chlorophyll a/c-binding protein (FCP) proteomic and transcriptomic analyses. The result demonstrated that HN promoted FX productivity by extending the exponential growth phase for higher biomass and FX accumulation stage (P1), showing a continuous increase in FX accumulation on day 6. Augmented FX biosynthesis via the upregulation of carotenogenesis could be primarily attributed to enhanced FCP formation in the thylakoid membrane. Key proteins, such as LHC3/4, LHCF8, LHCF5, and LHCF10, and key genes, such as PtPSY, PtPDS, and PtVDE, were upregulated under nitrogen repletion. Finally, the combination of low light and HN prolonged the P1 stage to day 10, resulting in maximal FX productivity to 9.82 ± 0.56 mg/L/day, demonstrating an effective strategy for enhancing FX production in microalgae cultivation.

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.

Microalgae as a Sustainable Source of Antioxidants in Animal Nutrition, Health and Livestock Development

Microalgae are a renewable and sustainable source of bioactive compounds, such as essential amino acids, polyunsaturated fatty acids, and antioxidant compounds, that have been documented to have beneficial effects on nutrition and health. Among these natural products, the demand for natural antioxidants, as an alternative to synthetic antioxidants, has increased. The antioxidant activity of microalgae significantly varies between species and depends on growth conditions. In the last decade, microalgae have been explored in livestock animals as feed additives with the aim of improving both animals' health and performance as well as product quality and the environmental impact of livestock. These findings are highly dependent on the composition of microalgae strain and their amount in the diet. The use of carbohydrate-active enzymes can increase nutrient bioavailability as a consequence of recalcitrant microalgae cell wall degradation, making it a promising strategy for monogastric nutrition for improving livestock productivity. The use of microalgae as an alternative to conventional feedstuffs is becoming increasingly important due to food-feed competition, land degradation, water deprivation, and climate change. However, the cost-effective production and use of microalgae is a major challenge in the near future, and their cultivation technology should be improved by reducing production costs, thus increasing profitability.

Effects of Temperature, Light and Salt on the Production of Fucoxanthin from Conticribra weissflogii

Fucoxanthin is a natural active substance derived from diatoms that is beneficial to the growth and immunity of humans and aquatic animals. Temperature, light and salinity are important environmental factors affecting the accumulation of diatom actives; however, their effects on the production of fucoxanthin in C. weissflogii are unclear. In this study, single-factor experiments are designed and followed by an orthogonal experiment to determine the optimal combination of fucoxanthin production conditions in C. weissflogii. The results showed that the optimum conditions for fucoxanthin production were a temperature of 30 °C, a light intensity of 30 umol m-2 s-1 and a salinity of 25. Under these conditions, the cell density, biomass, carotenoid content and fucoxanthin content of C. weissflogii reached 1.97 × 106 cell mL-1, 0.76 g L-1, 2.209 mg L-1 and 1.372 mg g-1, respectively, which were increased to 1.53, 1.71, 2.50 and 1.48 times higher than their initial content. The work sought to give useful information that will lead to an improved understanding of the effective method of cultivation of C. weissflogii for natural fucoxanthin production.

An unexpected hydratase synthesizes the green light-absorbing pigment fucoxanthin

The ketocarotenoid fucoxanthin and its derivatives can absorb blue-green light enriched in marine environments. Fucoxanthin is widely adopted by phytoplankton species as a main light-harvesting pigment, in contrast to land plants that primarily employ chlorophylls. Despite its supreme abundance in the oceans, the last steps of fucoxanthin biosynthesis have remained elusive. Here, we identified the carotenoid isomerase-like protein CRTISO5 as the diatom fucoxanthin synthase that is related to the carotenoid cis-trans isomerase CRTISO from land plants but harbors unexpected enzymatic activity. A crtiso5 knockout mutant in the model diatom Phaeodactylum tricornutum completely lacked fucoxanthin and accumulated the acetylenic carotenoid phaneroxanthin. Recombinant CRTISO5 converted phaneroxanthin into fucoxanthin in vitro by hydrating its carbon-carbon triple bond, instead of functioning as an isomerase. Molecular docking and mutational analyses revealed residues essential for this activity. Furthermore, a photophysiological characterization of the crtiso5 mutant revealed a major structural and functional role of fucoxanthin in photosynthetic pigment-protein complexes of diatoms. As CRTISO5 hydrates an internal alkyne physiologically, the enzyme has unique potential for biocatalytic applications. The discovery of CRTISO5 illustrates how neofunctionalization leads to major diversification events in evolution of photosynthetic mechanisms and the prominent brown coloration of most marine photosynthetic eukaryotes.

Two-phase microalgae cultivation for RAS water remediation and high-value biomass production

The overall goal of this study was to provide solutions to innovative microalgae-based technology for wastewater remediation in a cold-water recirculating marine aquaculture system (RAS). This is based on the novel concept of integrated aquaculture systems in which fish nutrient-rich rearing water will be used for microalgae cultivation. The produced biomass can be used as fish feed, while the cleaned water can be reused, to create a highly eco-sustainable circular economy. Here, we tested three microalgae species Nannochloropis granulata (Ng), Phaeodactylum tricornutum (Pt), and Chlorella sp (Csp) for their ability to remove nitrogen and phosphate from the RAS wastewater and simultaneously produce high-value biomass, i.e., containing amino acids (AA), carotenoids, and polyunsaturated fatty acids (PUFAs). A high yield and value of biomass were achieved for all species in a two-phase cultivation strategy: i) a first phase using a medium optimized for best growth (f/2 14x, control); ii) a second "stress" phase using the RAS wastewater to enhance the production of high-value metabolites. Ng and Pt performed best in terms of biomass yield (i.e., 5-6 g of dry weight, DW.L^-1) and efficient cleaning of the RAS wastewater from nitrite, nitrate, and phosphate (i.e., 100% removal). Csp produced about 3 g L^-1 of DW and reduced efficiently only nitrate, and phosphate (i.e., about 76% and 100% removal, respectively). The biomass of all strains was rich in protein (30-40 % of DW) containing all the essential AA except Methionine. The biomass of all three species was also rich in PUFAs. Finally, all tested species are excellent sources of antioxidant carotenoids, including fucoxanthin (Pt), lutein (Ng and Csp) and β-carotene (Csp). All tested species in our novel two-phase cultivation strategy thus showed great potential to treat marine RAS wastewater and provide sustainable alternatives to animal and plant proteins with extra added values.

Microalgae Produce Antioxidant Molecules with Potential Preventive Effects on Mitochondrial Functions and Skeletal Muscular Oxidative Stress

In recent years, microalgae have become a source of molecules for a healthy life. Their composition of carbohydrates, peptides, lipids, vitamins and carotenoids makes them a promising new source of antioxidant molecules. Skeletal muscle is a tissue that requires constant remodeling via protein turnover, and its regular functioning consumes energy in the form of adenosine triphosphate (ATP), which is produced by mitochondria. Under conditions of traumatic exercise or muscular diseases, a high production of reactive oxygen species (ROS) at the origin of oxidative stress (OS) will lead to inflammation and muscle atrophy, with life-long consequences. In this review, we describe the potential antioxidant effects of microalgae and their biomolecules on mitochondrial functions and skeletal muscular oxidative stress during exercises or in musculoskeletal diseases, as in sarcopenia, chronic obstructive pulmonary disease (COPD) and Duchenne muscular dystrophy (DMD), through the increase in and regulation of antioxidant pathways and protein synthesis.

Study on bioactive compounds of microalgae as antioxidants in a bibliometric analysis and visualization perspective

Natural antioxidants are more attractive than synthetic chemical oxidants because of their non-toxic and non-harmful properties. Microalgal bioactive components such as carotenoids, polysaccharides, and phenolic compounds are gaining popularity as very effective and long-lasting natural antioxidants. Few articles currently exist that analyze microalgae from a bibliometric and visualization point of view. This study used a bibliometric method based on the Web of Science Core Collection database to analyze antioxidant research on bioactive compounds in microalgae from 1996 to 2022. According to cluster analysis, the most studied areas are the effectiveness, the antioxidant mechanism, and use of bioactive substances in microalgae, such as carotene, astaxanthin, and tocopherols, in the fields of food, cosmetics, and medicine. Using keyword co-occurrence and keyword mutation analysis, future trends are predicted to improve extraction rates and stability by altering the environment of microalgae cultures or mixing extracts with chemicals such as nanoparticles for commercial and industrial applications. These findings can help researchers identify trends and resources to build impactful investigations and expand scientific frontiers.

Microalgae as a Nutraceutical Tool to Antagonize the Impairment of Redox Status Induced by SNPs: Implications on Insulin Resistance

Microalgae represent a growing innovative source of nutraceuticals such as carotenoids and phenolic compound which are naturally present within these single-celled organisms or can be induced in response to specific growth conditions. The presence of the unfavourable allelic variant in genes involved in the control of oxidative stress, due to one or more SNPs in gene encoding protein involved in the regulation of redox balance, can lead to pathological conditions such as insulin resistance, which, in turn, is directly involved in the pathogenesis of type 2 diabetes mellitus. In this review we provide an overview of the main SNPs in antioxidant genes involved in the promotion of insulin resistance with a focus on the potential role of microalgae-derived antioxidant molecules as novel nutritional tools to mitigate oxidative stress and improve insulin sensitivity.

Manipulation in Culture Conditions of Nanofrustulum shiloi for Enhanced Fucoxanthin Production and Isolation by Preparative Chromatography

Microalgae produce a variety of high-value chemicals including carotenoids. Fucoxanthin is also a carotenoid that has many physiological functions and biological properties. For this reason, the cost-effective production of fucoxanthin at an industrial scale has gained significant attention. In the proposed study, fucoxanthin production was aimed to be increased by altering the culture conditions of N. shiloi. The effect of light intensity aeration rate, different nitrogen sources, and oxidative stress on the biomass and fucoxanthin productivity have been discussed. Based on these results, the fucoxanthin increased to 97.45 ± 2.64 mg/g by adjusting the light intensity to 50 µmol/m²s, and aeration rate at 5 L/min using oxidative stress through the addition of 0.1 mM H₂O₂ and 0.1 mM NaOCl to the culture medium. Fucoxanthin was then purified with preparative HPLC using C₃₀ carotenoid column (10 mm × 250 mm, 5 μm). After the purification procedure, Liquid chromatography tandem mass spectrometry (LC-MS/MS) and UV-vis spectroscopy were employed for the confirmation of fucoxanthin. This study presented a protocol for obtaining and purifying considerable amounts of biomass and fucoxanthin from diatom by manipulating culture conditions. With the developed methodology, N. shiloi could be evaluated as a promising source of fucoxanthin at the industrial scale for food, feed, cosmetic, and pharmaceutical industries.