scholarly journals Differences between Motile and Nonmotile Cells of Haematococcus pluvialis in the Production of Astaxanthin at Different Light Intensities

Marine Drugs ◽  
2019 ◽  
Vol 17 (1) ◽  
pp. 39 ◽  
Author(s):  
Feng Li ◽  
Minggang Cai ◽  
Mingwei Lin ◽  
Xianghu Huang ◽  
Jun Wang ◽  
...  
Keyword(s):  
Light Intensity ◽  
Induction Period ◽  
Cell Cultures ◽  
Haematococcus Pluvialis ◽  
Light Intensities ◽  
Motile Cells ◽  
Cell Mortality ◽  
Astaxanthin Production ◽  
Major Cell Type ◽  
The Stability

Haematococcus pluvialis, as the best natural resource of astaxanthin, is widely used in nutraceuticals, aquaculture, and cosmetic industries. The purpose of this work was to compare the differences in astaxanthin accumulation between motile and nonmotile cells of H. pluvialis and to determine the relationship between the two cells and astaxanthin production. The experiment design was achieved by two different types of H. pluvialis cell and three different light intensities for an eight day induction period. The astaxanthin concentrations in nonmotile cell cultures were significantly increased compared to motile cell cultures. The increase of astaxanthin was closely associated with the enlargement of cell size, and the nonmotile cells were more conducive to the formation of large astaxanthin-rich cysts than motile cells. The cyst enlargement and astaxanthin accumulation of H. pluvialis were both affected by light intensity, and a general trend was that the higher the light intensity, the larger the cysts formed, and the larger the quantity of astaxanthin accumulated. In addition, the relatively low cell mortality rate in the nonmotile cell cultures indicated that the nonmotile cells have a stronger tolerance to photooxidative stress. We suggest that applying nonmotile cells as the major cell type of H. pluvialis to the induction period may help to enhance the content of astaxanthin and the stability of astaxanthin production.

Effects of gradual and sudden changes of salinity and light supply for astaxanthin production in Haematococcus pluvialis (Chlorophyceae)

2020 ◽  
Vol 194 (1) ◽  
pp. 11-17
Author(s):  
Murat Telli ◽  
Günce Ahin
Keyword(s):  
Cell Viability ◽  
Induction Period ◽  
Salt Concentration ◽  
Haematococcus Pluvialis ◽  
Dry Mass ◽  
Final Concentration ◽  
Food Industries ◽  
Light Supply ◽  
Astaxanthin Production ◽  
Biomass Loss

Astaxanthin, a carotenoid naturally synthesized by Haematococcus pluvialis, is economically important for the nutraceutical, pharmaceutical and food industries due to its high antioxidant and anti-inflammatory properties. We investigated astaxanthin accumulation in H. pluvialis after stepwise versus suddenly increased light supply and salt (NaCl) concentrations. Light was increased from 75 to 150, and then to the final intensity of 350 μmol photons m –2 s–1 in three-day intervals. The effect of gradually increased salt concentration was examined with two steps from 0.2 to the final concentration of 0.8 % (w/v) in three-day intervals. The overall induction period for astaxanthin accumulation was 13 days. Out of all treatments, stepwise increased light supply resulted in highest cell viability and highest astaxanthin accumulation with 15.76 ± 0.88 mg g –1 dry mass. It is an energy-saving, appropriate strategy to achieve optimal astaxanthin accumulation. It moreover resulted in the least biomass loss, which is caused by the provided stress conditions.

scholarly journals Biomass and Astaxanthin Productivities of Haematococcus pluvialis in an Angled Twin-Layer Porous Substrate Photobioreactor: Effect of Inoculum Density and Storage Time

Biology ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 68 ◽  
Author(s):  
Thanh-Tri Do ◽  
Binh-Nguyen Ong ◽  
Minh-Ly Nguyen Tran ◽  
Doan Nguyen ◽  
Michael Melkonian ◽  
...  
Keyword(s):  
Haematococcus Pluvialis ◽  
Dry Weight ◽  
Porous Substrate ◽  
Light Intensities ◽  
Alternative Approach ◽  
Dry Biomass ◽  
Astaxanthin Production ◽  
Astaxanthin Content ◽  
Storage Times ◽  
And Storage

The microalga Haematococcus pluvialis is mainly cultivated in suspended systems for astaxanthin production. Immobilized cultivation on a Twin-Layer porous substrate photobioreactor (TL-PSBR) has recently shown promise as an alternative approach. In Vietnam, a TL-PSBR was constructed as a low-angle (15 °) horizontal system to study the cultivation of H. pluvialis for astaxanthin production. In this study, the biomass and astaxanthin productivities and astaxanthin content in the dry biomass were determined using different initial biomass (inoculum) densities (from 2.5 to 10 g dry weight m−2), different storage times of the initial biomass at 4 °C (24, 72, 120 and 168 h) and different light intensities (300–1000 µmol photons m−2 s−1). The optimal initial biomass density at light intensities between 400–600 µmol photons−2 s−1 was 5–7.5 g m−2. Algae stored for 24 h after harvest from suspension for immobilization on the TL-PSBR yielded the highest biomass and astaxanthin productivities, 8.7 g m−2 d−1 and 170 mg m−2 d−1, respectively; longer storage periods decreased productivity. Biomass and astaxanthin productivities were largely independent of light intensity between 300–1000 µmol photons m−2 s−1 but the efficiency of light use per mole photons was highest between 300–500 µmol photons m−2 s−1. The astaxanthin content in the dry biomass varied between 2–3% (w/w). Efficient supply of CO2 to the culture medium remains a task for future improvements of angled TL-PSBRs.

scholarly journals Enhanced Biomass and Astaxanthin Production of Haematococcus pluvialis by a Cell Transformation Strategy with Optimized Initial Biomass Density

Marine Drugs ◽  
2020 ◽  
Vol 18 (7) ◽  
pp. 341
Author(s):  
Feng Li ◽  
Minggang Cai ◽  
Mingwei Lin ◽  
Xianghu Huang ◽  
Jun Wang ◽  
...  
Keyword(s):  
Cell Death ◽  
Cell Transformation ◽  
Haematococcus Pluvialis ◽  
Cost Effective ◽  
Control Group ◽  
Biomass Density ◽  
Cost Effective Method ◽  
Astaxanthin Production ◽  
The Stability ◽  
Transformation Strategy

Astaxanthin from H. pluvialis is an antioxidant and presents a promising application in medicine for human health. The two-stage strategy has been widely adopted to produce astaxanthin by the Haematococcus industry and research community. However, cell death and low astaxanthin productivity have seriously affected the stability of astaxanthin production. This study aims to test the effect of cell transformation strategies on the production of astaxanthin from H. pluvialis and determine the optimal initial biomass density (IBD) in the red stage. The experimental design is divided into two parts, one is the vegetative growth experiment and the other is the stress experiment. The results indicated that: (1) the cell transformation strategy of H. pluvialis can effectively reduce cell death occurred in the red stage and significantly increase the biomass and astaxanthin production. (2) Compared with the control group, the cell mortality rate of the red stage in the treatment group was reduced by up to 81.6%, and the biomass and astaxanthin production was increased by 1.63 times and 2.1 times, respectively. (3) The optimal IBD was determined to be 0.5, and the highest astaxanthin content can reach 38.02 ± 2.40 mg·g−1. Thus, this work sought to give useful information that will lead to an improved understanding of the cost-effective method of cultivation of H. pluvialis for natural astaxanthin. This will be profitable for algal and medicine industry players.

Battery Charge Affects the Stability of Light Intensity from Light-emitting Diode Light-curing Units

2017 ◽  
Vol 42 (5) ◽  
pp. 497-504 ◽  
Author(s):  
A Tongtaksin ◽  
C Leevailoj
Keyword(s):  
Light Intensity ◽  
Light Emitting Diode ◽  
Resin Composite ◽  
Bottom Surface ◽  
Light Emitting ◽  
Led Light ◽  
Battery Charge ◽  
Light Intensities ◽  
Light Curing ◽  
The Stability

SUMMARY This study investigated the influence of battery charge levels on the stability of light-emitting diode (LED) curing-light intensity by measuring the intensity from fully charged through fully discharged batteries. The microhardness of resin composites polymerized by the light-curing units at various battery charge levels was measured. The light intensities of seven fully charged battery LED light-curing units—1) LY-A180, 2) Bluephase, 3) Woodpecker, 4) Demi Plus, 5) Saab II, 6) Elipar S10, and 7) MiniLED—were measured with a radiometer (Kerr) after every 10 uses (20 seconds per use) until the battery was discharged. Ten 2-mm-thick cylindrical specimens of A3 shade nanofilled resin composite (PREMISE, Kerr) were prepared per LED light-curing unit group. Each specimen was irradiated by the fully charged light-curing unit for 20 seconds. The LED light-curing units were then used until the battery charge fell to 50%. Specimens were prepared again as described above. This was repeated again when the light-curing units' battery charge fell to 25% and when the light intensity had decreased to 400 mW/cm2. The top/bottom surface Knoop hardness ratios of the specimens were determined. The microhardness data were analyzed by one-way analysis of variance with Tukey test at a significance level of 0.05. The Pearson correlation coefficient was used to determine significant correlations between surface hardness and light intensity. We found that the light intensities of the Bluephase, Demi Plus, and Elipar S10 units were stable. The intensity of the MiniLED unit decreased slightly; however, it remained above 400 mW/cm2. In contrast, the intensities of the LY-A180, Woodpecker, and Saab II units decreased below 400 mW/cm2. There was also a significant decrease in the surface microhardnesses of the resin composite specimens treated with MiniLED, LY-A180, Woodpecker, and Saab II. In conclusion, the light intensity of several LED light-curing units decreased as the battery was discharged, with a coincident reduction in the units' ability to polymerize resin composite. Therefore, the intensity of an LED light-curing unit should be evaluated during the life of its battery charge to ensure that sufficient light intensity is being generated.

scholarly journals Comparative transcriptome analysis of astaxanthin accumulation difference between non-motile cells and akinetes of Haematococcus pluvialis

2020 ◽  
Author(s):  
Lei Fang ◽  
Jingkui Zhang ◽  
Zhongnan Fei ◽  
Minxi Wan
Keyword(s):  
Transcriptome Analysis ◽  
Haematococcus Pluvialis ◽  
Synthesis Mechanism ◽  
Motile Cells ◽  
Genes Expression ◽  
Malonyl Coa ◽  
Astaxanthin Production ◽  
Culture Process ◽  
Photosynthesis Genes ◽  
Accumulation Ability

Abstract Background: Nature astaxanthin is mainly derived from Haematococcus pluvialis. H. pluvialis has four kinds of cell morphology. Based on sequential heterotrophy-dilution-photoinduction (SHDP) technology, photoinduction using non-motile cells as seeds could result in a higher astaxanthin production than that of using brown akinetes as photoinduction seeds. To have a comprehensive understanding of this phenomenon, transcriptome analysis was conducted in this study.Results: Though most of photosynthesis genes expression were down-regulated during the SHDP culture process. Comparing with the group using brown akinetes as photoinduction seeds, the genes expression involved in astaxanthin biosynthesis, lipid biosynthesis and photosynthesis were up-regulated in the non-motile cells group. Especially, chyb gene improving the conversion of β-carotene into astaxanthin was up-regulated by 2.6-fold. The acaca gene enhancing the carboxylation of acetyl-CoA to malonyl-CoA was up-regulated by 1.4-fold.Conclusions: Astaxanthin synthesis mechanism of non-motile cells with higher astaxanthin accumulation ability than brown akinetes was attributed to the up-regulation of astaxanthin metabolism, lipid metabolism and photosynthesis-related genes expression. The results are expected to guide the optimization of astaxanthin production in H. pluvialis by improving lipid content or photosynthesis.

scholarly journals Accumulation of Astaxanthin Was Improved by the Nonmotile Cells of Haematococcus pluvialis

2019 ◽  
Vol 2019 ◽  
pp. 1-7 ◽  
Author(s):  
Feng Li ◽  
Minggang Cai ◽  
Mingwei Lin ◽  
Xianghu Huang ◽  
Jun Wang ◽  
...  
Keyword(s):  
Mortality Rate ◽  
Cell Cultures ◽  
Haematococcus Pluvialis ◽  
Morphological Changes ◽  
Continuous Light ◽  
Motile Cell ◽  
Cell Diameter ◽  
Batch Mode ◽  
Vegetative Cells ◽  
Motile Cells

The current commercial production of natural astaxanthin is mainly carried out using Haematococcus pluvialis vegetative cells in the “two-stage” batch mode. The motile vegetative cells are more sensitive to stress than nonmotile vegetative cells, thereby affecting the overall astaxanthin productivity in H. pluvialis cultures. In this study, we compared the differences between motile cells and nonmotile cells in astaxanthin productivity, morphological changes, the mortality rate, and the diameter of the formed cysts. The experimental design was achieved by two different types H. pluvialis cell under continuous light of 80 μmol photons m−2 s−1 for a 9-day induction period. The highest astaxanthin concentration of 48.42 ± 3.13 mg L−1 was obtained in the nonmotile cell cultures with the highest the productivity of 5.04 ± 0.15 mg L−1 day−1, which was significantly higher than that in the motile cell cultures. The microscopic examination of cell morphological showed a large number of photooxidative damaged cells occurring in the motile cell cultures, resulting in higher cell mortality rate (22.2 ± 3.97%) than nonmotile cell cultures (9.6 ± 0.63%). In addition, the analysis results of cell diameter statistics indicated that nonmotile cells were more conducive to the formation of large astaxanthin-rich cysts than motile cells. In conclusion, the works presented here suggest that the accumulation of astaxanthin was significantly improved by nonmotile cells of H. pluvialis, which provided a possibility of optimizing the existing H. pluvialis cultivation strategy for the industrial production.

scholarly journals THE INDUCTION PERIOD IN PHOTOSYNTHESIS

1937 ◽  
Vol 21 (2) ◽  
pp. 151-163 ◽  
Author(s):  
Emil L. Smith
Keyword(s):  
Light Intensity ◽  
Induction Period ◽  
Stationary State ◽  
High Light ◽  
Dark Reaction ◽  
Co2 Concentrations ◽  
Light Intensities ◽  
Period Equation ◽  
Cabomba Caroliniana

1. Measurements on the photosynthesis of Cabomba caroliniana show an induction period at low and high light intensities and CO2 concentrations. 2. The equation which describes the data for Cabomba also describes the data obtained by other investigators on different species. The phenomenon is thus shown to be similar in plants representative of three phyla. 3. A derivation of the induction period equation is made from a consideration of the cycle of light and dark processes known to occur in photosynthesis. The equation indicates that light intensity enters as the square, and that the same light reactions are involved as those which affect the stationary state rates. However, a different dark reaction appears to limit photosynthesis during the induction period.

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