• Journal of Microbiology and Biotechnology
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• v.18 no.12
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• pp.1990-1996
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• 2008

Astaxanthin has shown antioxidant, antitumor, and anti-inflammatory activities; however, its molecular action and mechanism in the nervous system have yet to be elucidated. We examined the in vitro effects of astaxanthin on the production of nitric oxide (NO), as well as the expression of inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2) in lipopolysaccharide (LPS)-stimulated BV2 microglial cells. Astaxanthin inhibited the expression or formation of nitric oxide (NO), iNOS and COX-2 in lipopolysaccharide (LPS)-stimulated BV-2 microglial cells. Astaxanthin also suppressed the protein levels of iNOS and COX-2 in LPS-stimulated BV2 microglial cells. These results suggest that astaxanthin, probably due to its antioxidant activity, inhibits the production of inflammatory mediators by blocking iNOS and COX-2 activation or by the suppression of iNOS and COX-2 degradation.

• Journal of Marine Bioscience and Biotechnology
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• v.6 no.1
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• pp.31-40
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• 2014

The production of astaxanthin in the microalga Haematococcus pluvialis has been investigated using a sequential methodology based on the application of two types of statistical designs. The employed preliminary experiment was a fractional factorial design $2^6$ in which the factors studied were: excessive irradiance and nitrate starvation, phosphate deficiency, acetate supplementation, salt stress, and elevated temperature. The experimental results indicate that the amount of astaxanthin accumulation in the cells can be enhanced by excessive irradiance and nitrate starvation whereas the other factors tested did not yield any enhancement. In the subsequent experiment, a central composite design was applied with four variables, light intensity, nitrate, phosphate, and acetate, at five levels each. The optimal conditions for the highest astaxanthin production were found to be $1040{\mu}E/(m^2{\cdot}s)$ light intensity, 0.04 g/L nitrate, 0.31 g/L phosphate, 0.05 g/L acetate concentration.

• Microbiology and Biotechnology Letters
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• v.29 no.4
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• pp.227-233
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• 2001

To maximize astaxanthin (3,3'-dihydroxy-$\beta\beta$'carotene-44'-dione) production by high density Haematococcus pluvialis cultures, various, media were examined Among tested media, \`Hong Kong Medium and Modified Bolds Basal Medium showed the best result for cell growth ( $2.0$\times$10^{ 6}$cells /mL) and for astaxanthin content per cell (9.7 mg astaxanthin mg/g cell), respectively, Maximum astasanthin concentration of 6.1mL was obtained at pH 7.5, $20^{\circ}C$~$25^{\circ}C$ Deficiencies of nitrogen source($NaNO_3$ and proteose-peptone) found to simulate astaxanthin formation Relatively low light inten- sity of $60\mu$E ($\m^2$s) was sutiable for vegetative cell growth while higher light intensity was required for higher astaxanthin accumulation.

• ALGAE
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• v.24 no.2
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• pp.121-127
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• 2009

The unicellular green alga, Haematococcus pluvialis, accumulates the highest level of astaxanthin among knownastaxanthi.n-producing organisms. Light is the most important factor to induce astaxanthin by H. pluvialis. BIue andred LEDs, whose ${\lambda}_{max}$'s are 470 and 665 nm, respectively, were used for internally illuminated light sources.Fluorescent lamps were also used for both internal and external illumination sources. The astaxanthin levels in thesevarious lighting systems were analyzed and compared each other. The cultures under internally illuminated LEDsaccumulaled 20% more astaxanthin than those under fluorescent lamp. Furthermore, LEDs generated much lessheat than the fluorescent lamps, which gives one more reason for the LEDs being a suitable internal Light source forastaxanthin induction. The results reported here would lead novel designs of photobioreactors with improvementsof illumination methods for high level of astaxanthm production. The maximum astaxanthin concentrations as wellas the astaxanthin yield per supplied photon were increased by at least 20% when blue or red LEDs were supplied.

• Journal of Life Science
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• v.25 no.12
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• pp.1339-1346
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• 2015

The aim of this study is to increase production of carotenoids in recombinant Escherichia coli by Archaea chaperonin. The carotenoids are a widely distributed class of structurally and functionally diverse yellow, orange, and red natural pigments. These pigments are synthesized in bacteria, algae, fungi, and plants, and have been widely used as a feed supplement from poultry rearing to aquaculture. Carotenoids also exhibit diverse biological properties, such as strong antioxidant and antitumor activities, and enhancement of immune responses. In the microbial world, carotenoids are present in both anoxygenic and oxygenic photosynthetic bacteria and algae and in many fungi. We have previously reported cloning and functional analysis of the carotenoid biosynthesis genes from Paracoccus haeundaensis. The carotenogenic gene cluster involved in astaxanthin production contained seven carotenogenic genes (crtE, crtB, crtI, crtY, crtZ, crtW and crtX genes) and recombinant Escherichia coli harboring seven carotenogenic genes from Paracoccus haeundaensis produced 400 μg/g dry cell weight (DCW) of astaxanthin. In order to increase production of astaxanthin, we have co-expressed chaperone genes (ApCpnA and ApCpnB) in recombinant Escherichia coli harboring the astaxanthin biosynthesis genes. This engineered Escherichia coli strain containing both chaperone gene and astaxanthin biosynthesis gene cluster produced 890 μg/g DCW of astaxanthin, resulting 2-fold increased production of astaxanthin.

• Journal of Life Science
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• v.18 no.12
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• pp.1764-1770
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• 2008

The goal of this study is to increase production of astaxanthin in recombinant Escherichia coli by engineered isoprenoid pathway. We have previously reported structural and functional analysis of the astaxanthin biosynthesis genes from a marine bacterium, Paracoccus haeundaensis. The carotenoid biosynthesis gene cluster involved in astaxanthin production contained six carotenogenic genes (crtW, crtZ, crtY, crtI, crtB, and crtE genes) and recombinant E. coli harboring six carotenogenic genes from P. haeundaensis produced 400 ${\mu}g$/g dry cell weight (DCW) of astaxanthin. In order to increase production of astaxanthin in recombinant E. coli, we have cloned 4-hydroxy-3-methylbut-2-enyl diphosphate reductase (lytB), farnesyl diphosphate (FPP) synthase (ispA), and isopentenyl (IPP) diphossphate isomerase (idi) in the isoprenoid pathway from E. coli and coexpressed these genes in recombinant E. coli harboring the astaxanthin biosynthesis genes. This engineered E. coli strain containing both isoprenoid pathway gene and astaxanthin biosynthesis gene cluster produced 1,200 ${\mu}g$/g DCW of astaxanthin, resulting 3-fold increased production of astaxanthin.

• Journal of Microbiology and Biotechnology
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• v.21 no.10
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• pp.1081-1087
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• 2011

An internally radiating photobioreactor was applied for the production of astaxanthin using the unicellular green alga Haematococcus pluvialis. The cellular morphology of H. pluvialis was significantly affected by the intensity of irradiance of the photobioreactor. Small green cells were widespread under lower light intensity, whereas big reddish cells were predominant under high light intensity. For these reasons, growth reflected by cell number or dry weight varied markedly with light conditions. Even under internal illumination of the photobioreactor, light penetration was significantly decreased as algal cells grew. Therefore, we employed a multistage process by gradually increasing the internal illuminations for astaxanthin production. Our results revealed that a multistage process might be essential to the successful operation of a photobioreactor for astaxnthin production using H. pluvialis.

• Journal of Microbiology and Biotechnology
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• v.11 no.6
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• pp.1024-1030
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• 2001

The key factors for high-density Haematococcus pluvialis cultures and conditions for astaxanthin induction were examined to maximize astaxanthin production. Light intensity was found to be the most important factor, and thus experiments were found to be the most important factor, and thus experiments were carried out using different light sources and intensities. A high cell density of over 2.7 g/l was obtained at $75{\mu}E/m^2/s$, whereas a much lower cell concentration (<1.0 g/ 1) was obtained with lower light intensities $(15-30{\mu}E/m^2/s$. A high light intensity and the supplement of 470 nm photons had a more dramatic effect on the final astaxanthin concentration and per cell astaxanthin content. A maximum astaxanthin concentration of 6.5 mg/l was obtained at a light intensity of $160{\mu}E/m^2/s$, whereas only 1.3 and 0.7 mg/l were obtained at 30 and $15{\mu}E/m^2/s$, respectively. A supplement of 470 nm photons enhanced the carotenoid and chlorophyll formation.

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.6
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• pp.799-805
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• 2010

Since the consumption of spent laying hens as roasted skewered meat increases, the effects of various carotenoids on pigmentation and antioxidant activity were tested with 62-wk-old 250 ISA brown laying hens to improve the quality of chicken meat. In a 6-wk feeding trial, 4 carotenoids with different polarity (${\beta}$-8-apo-carotenoic acid ethyl ester (ACAEE)>astaxanthin>canthaxanthin>${\beta}$-carotene) at 100 mg carotenoid/kg feed were used. The more polar the carotenoids, the higher were the levels in blood. After 5-wk adaptation, the concentrations of astaxanthin, canthaxanthin, and ACAEE in blood were -4 ${\mu}g/ml$. Canthaxanthin decreased significantly (p<0.05) the level of total blood cholesterol. Decreases in blood triglyceride by all carotenoids used were significant. ACAEE and astaxanthin tended to increase skin yellowness of thigh, breast, and wing proportionally to feeding period. In the case of polar carotenoids (ACAEE and astaxanthin), the longer the period of feeding, the higher the accumulation in skin was observed. Only astaxanthin was effective against the production of lipid peroxides in skin. Conclusively, out of the commercially available carotenoids we tested, astaxanthin is recommended for pigmentation of skin and inhibition of lipid oxidation.

• ALGAE
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• v.28 no.2
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• pp.131-147
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• 2013

Major progress has been made in the past decade towards understanding of the biosynthesis of red carotenoid astaxanthin and its roles in stress response while exploiting microalgae-based astaxanthin as a potent antioxidant for human health and as a coloring agent for aquaculture applications. In this review, astaxanthin-producing green microalgae are briefly summarized with Haematococcus pluvialis and Chlorella zofingiensis recognized to be the most popular astaxanthin-producers. Two distinct pathways for astaxanthin synthesis along with associated cellular, physiological, and biochemical changes are elucidated using H. pluvialis and C. zofingiensis as the model systems. Interactions between astaxanthin biosynthesis and photosynthesis, fatty acid biosynthesis and enzymatic defense systems are described in the context of multiple lines of defense mechanisms working in concert against photooxidative stress. Major pros and cons of mass cultivation of H. pluvialis and C. zofingiensis in phototrophic, heterotrophic, and mixotrophic culture modes are analyzed. Recent progress in genetic engineering of plants and microalgae for astaxanthin production is presented. Future advancement in microalgal astaxanthin research will depend largely on genome sequencing of H. pluvialis and C. zofingiensis and genetic toolbox development. Continuous effort along the heterotrophic-phototrophic culture mode could lead to major expansion of the microalgal astaxanthin industry.