• 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 Microbiology and Biotechnology
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• v.28 no.12
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• pp.2019-2028
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• 2018

Natural astaxanthin mainly derives from a microalgae producer, Haematococcus pluvialis. The induction of nitrogen starvation and high light intensity is particularly significant for boosting astaxanthin production. However, the different responses to light intensity and nitrogen starvation needed to be analyzed for biomass growth and astaxanthin accumulation. The results showed that the highest level of astaxanthin production was achieved in nitrogen starvation, and was 1.64 times higher than the control group at 11 days. With regard to the optimization of light intensity utilization, it was at $200{\mu}mo/m^2/s$ under nitrogen starvation that the highest astaxanthin productivity per light intensity was achieved. In addition, both high light intensity and a nitrogen source had significant effects on multiple indicators. For example, high light intensity had a greater significant effect than a nitrogen source on biomass dry weight, astaxanthin yield and astaxanthin productivity; in contrast, nitrogen starvation was more beneficial for enhancing astaxanthin content per dry weight biomass. The data indicate that high light intensity synergizes with nitrogen starvation to stimulate the biosynthesis of astaxanthin.

• Journal of Microbiology and Biotechnology
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• v.20 no.9
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• pp.1276-1282
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• 2010

In traditional mixotrophic cultures of microalgae, all the inorganic nutrients and organic carbon sources are supplied in the medium before inoculation. In this study, however, an alternative approach was adopted in Haematococcus pluvialis Flotow, a microalga capable of growing mixotrophically on sodium acetate (Na-Ac). First, the cells were grown under 75 ${\mu}Mol$ photons $m^{-2}s^{-1}$ phototrophically without Na-Ac until the stationary phase and then exposed to five different light regimes by the addition of Na-Ac (e.g., dark, 20, 40, 75, and 150 ${\mu}Mol$ photons $m^{-2}s^{-1}$). Dry weight (DW), pigments, and especially cell number in alternative mixotrophy (AM) were higher than traditional mixotrophy (TM). Cell number in AM almost doubled up from 21.7 to $42.9{\times}10^4$ cells/ml during 5-day exposure to Na-Ac, whereas the increase was only 1.2-fold in TM. Maximum cell density was reached in 75 ${\mu}Mol$ photons $m^{-2}s^{-1}$ among the light intensities tested. We propose that Na-Ac in TM of H. pluvialis can not be utilized as efficiently as in AM. With this respect, AM has several advantages against TM such as a much higher cell density in a batch culture period and minimized risk of contamination owing to the shorter exposure of cells to organic carbon sources. In consequence, this method may be used for other strains of the species, and even for the other microalgal species able to grow mixotrophically.

• 한국생물공학회:학술대회논문집
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• 2005.10a
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• pp.216-217
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• 2005

• Korean Chemical Engineering Research
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• v.56 no.3
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• pp.376-380
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• 2018

The astaxanthin recovery efficiencies were compared in acetonitrile, acetone, methanol, dichloromethane : methanol (1:3, v/v) and ethylacetate : ethanol (1:1, v/v) as a extraction solvent after the grinding of the H. pluvialis cells. The astaxanthin extraction yield in acetone was 1.13~1.29 times higher than other extraction solvents. It was also found that 96.7% of astaxanthin accumulated in H. pluvialis could be recovered by a single extraction. Since astaxanthin exists mainly as astaxanthin esters in H. pluvialis, a gradient reversed-phase HPLC analysis was carried out for the separation of astaxanthin esters from the extracts of H. pluvialis. Among the astaxanthin inside the H. pluvialis cell, free astaxanthin was 45.9% and astaxanthin esters were the rest.

• Journal of Microbiology and Biotechnology
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• v.16 no.8
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• pp.1222-1228
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• 2006

Two kinds of Haematococcus pluvialis cells (green vegetative cells cultivated under optimal cell culture conditions and red cyst cells maintained under high light stress conditions to induce astaxanthin production) were used to investigate the protein expression profiles by two-dimensional electrophoresis, image analysis, and peptide mass fingerprinting. The cellular accumulation of astaxanthin was evident after exposure to high light intensity and reached the maximum cellular level after 78 h of high light stress. In a 2-D electrophoresis analysis, 22 proteins were upregulated over 2-fold in the red cyst cells when compared with the green vegetative cells and selected for further analysis by chemically assisted fragmentation (CAF)-MALDI-TOF sequencing to identify the protein functions. Among 22 different spots, several key enzymes specific to the carotenoid pathway, including isopentenyl pyrophosphate isomerase (IPP) and lycopene $\beta$-cyclase, appeared in H. pluvialis after exposure to high light intensity. Therefore, IPP and lycopene $\beta$-cyclase would appear to be involved with carotenoid accumulation in the cytoplasm, as these peptides were preferentially upregulated by high light intensity preceding an increase in carotenoid, and only these forms were detected in the red cyst cells.

• 한국생물공학회:학술대회논문집
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• 2002.04a
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• pp.220-223
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• 2002

This study investigated a lab-scale inducing method for efficient astaxanthin accumulation. As a model system. Haematococcus pluvialis was cultivated in 2 liter bubble-column photobioreactors. The astaxanthin - inducing results using high light irradiation were compared with that of the control experiment under standard irradiation (40 ${\mu}E/m^2/s$). After the late linear growth phase (> 20 days). high light energy (230 ${\mu}E/m^2/s$) was supplied to the culture broth for astaxanthin induction. As a result. the dr γ cell weight and the astaxanthin productivity were increased up to 68% and 215%, respectively. higher than those of the control experiment. This result indicates that bubble-column type photobioreactor is a good candidate for mass cultivation of H. pluvialis and high light irradiation is an efficient induction method for astaxanthin accumulation in lab-scale bubble-column photobioreactors.

• Transactions of the Korean hydrogen and new energy society
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• v.24 no.3
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• pp.255-263
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• 2013

Carbon dioxide reduction technologies using photosynthetic microorganism were suggested to overcome environmental destruction caused by $CO_2$ in flue gases from power plant and other industries. However, there are many toxic constituents in flue gas including CO, NOx, SOx. Continuous and Excessive supply of these noxious gases to cells will leads to inhibition of microalgal growth along with partial cell death. In this study, we tested the noxious effect of SOx and NOx on the pH and microalgal growth under photoautotrophic culture in three microalgae of Neochloris oleoabundans, Chlorella vulgaris and Haematococcus pluvialis. As a result, SOx concentration more than 50 ppm led to the rapid reduction of pH, thereby inhibiting of the growth in Neochloris oleoabundans and Chlorella vulgaris. NOx concentration more the 100 ppm reduced the exponential growth of N. oleoabundans and C. vulgaris. And H. pluvialis exhibited low sensitivity to SOx and NOx. Consequently, the three microalgae of N. oleabundas, C. vulagaris and H. pluvialis showed the normal vegetative growth in 25 ppm of NOx and SOx. Above all, H. pluvialis was useful for the $CO_2$ sequestration of the flue gas including high concentrations of NOx and SOx.

• Journal of Microbiology and Biotechnology
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• v.16 no.12
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• pp.1890-1896
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• 2006

Lumostatic operation for cultivation of Haematococcus pluvialis was assessed to test the scale-up strategy of photobioreactors. Lumostatic operation is a method of maintaining a proper light condition based on the specific light uptake rate ($q_e$), by cells. Lumostatic operations were performed in 0.4-, 2-, 10-, and 30-1 scale bubble column photobioreactors and the results were compared with cultures illuminated with constant light intensity. Significant differences were observed in the maximal cell concentrations obtained from 0.4-, 2-, 10-, and 30-1 scale photobioreactors under constant light intensity, yielding the maximal cell concentrations of $2.8{\times}10^5$, $2.2\times10^5$, $1.5\times10^5$, and $1.1\times10^5$ cells/ml, respectively. The maximal cell concentration in a 0.4-1 photobioreactor under lumostatic operation was $4.3\times10^5$ cells/ml. Furthermore, those in 2-, 10-, and 30-1 scale photobioreactors were about the same as that in the 0.4-1 photobioreactor. The results suggest that lumostatic operation with proper $q_e$ is a good strategy for increasing the cell growth of Haematococcus pluvialis compared with a constant supply of light energy. Therefore, lumostatic operation is not only an efficient way to achieve high cell density cultures with minimal power consumption in microalgal cultures but it is also a perfect parameter for the scale-up of photobioreactors.

• 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.