The Experts below are selected from a list of 3696 Experts worldwide ranked by ideXlab platform
Feng Chen - One of the best experts on this subject based on the ideXlab platform.
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Indirect photometric ion chromatographic analysis of anions in Haematococcus pluvialis culture media
Biotechnology Letters, 2001Co-Authors: Jian-ping Yuan, Feng ChenAbstract:An indirect photometric ion chromatographic method for the simultaneous determination of chloride, nitrate and sulfate ions was developed and applied to the determination of anions, mainly nitrate, in the alga Haematococcus pluvialis culture media. Using phthalic acid/sodium tetraborate aqueous solution as the mobile phase, anions can be detected indirectly by a UV detector. The calibration curves for these anions gave good linearity from 1 to 1000 μg ml−1.
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Purification of trans-astaxanthin from a high-yielding astaxanthin ester-producing strain of the microalga Haematococcus pluvialis
Food Chemistry, 2000Co-Authors: Jian-ping Yuan, Feng ChenAbstract:The purification method including extraction, saponification, and separation was established for preparing free trans-astaxanthin from a high-yielding astaxanthin ester-producing strain of the microalga Haematococcus pluvialis which contained 3.67% trans-astaxanthins and 1.35% cis-astaxanthins of the dry cells. Low temperature (5°C) was chosen to minimize the degradation of astaxanthins during saponification, and 94.4% free trans-astaxanthin was obtained from trans-astaxanthin esters after 12 h of saponification. With this method, 32.2 mg trans-astaxanthin was obtained from 1 g dry algal cells. In addition, a new gradient reversed-phase HPLC method, suited for the quick analysis of free astaxanthins and astaxanthin esters in the unsaponified and saponified pigment extracts from the high-yielding astaxanthin ester-producing strain of the microalga Haematococcus pluvialis, was developed and applied to the determination of astaxanthin contents during the processes of extraction, saponification, and purification.
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Chromatographic separation and purification of trans-astaxanthin from the extracts of Haematococcus pluvialis
Journal of Agricultural and Food Chemistry, 1998Co-Authors: Jian-ping Yuan, Feng ChenAbstract:A gradient reversed-phase HPLC method was developed for the separation of astaxanthin esters and the isomers of astaxanthin from the unsaponified and saponified pigment extracts of the microalga Haematococcus pluvialis. Four kinds of isomers of astaxanthin and astaxanthin esters, (3S,3‘S)-trans-astaxanthin, (3S,3‘S)-9-cis-astaxanthin, (3S,3‘S)-13-cis-astaxanthin, (3R,3‘R)-trans-astaxanthin, and their esters, were separated and identified. A small amount of (3S,3‘S)-15-cis-astaxanthin was also detected from the saponified extract. In addition, a chromatographic purification method was established for the preparation of natural trans-astaxanthin from the saponified extract of H. pluvialis. With this method, 3.7 mg of astaxanthin was isolated from 1 g of dry biomass of H. pluvialis. The purified astaxanthin contained approximately 97.7% trans-astaxanthin, 1.1% cis-astaxanthin, and 1.2% impurity. Keywords: Astaxanthin; astaxanthin esters; purification; carotenoids; Haematococcus pluvialis; HPLC
Qing Huang - One of the best experts on this subject based on the ideXlab platform.
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Exogenous γ-aminobutyric acid promotes biomass and astaxanthin production in Haematococcus pluvialis
Algal Research, 2020Co-Authors: Zhu Chen, Qing HuangAbstract:Abstract Haematococcus pluvialis is one of most efficient organisms of producing astaxanthin. To achieve high astaxanthin yield, one strategy in the microalgae industry is to promote growth and biomass of Haematococcus pluvialis. For this purpose, we applied γ-aminobutyric acid (GABA) in the cultivation system and found it could significantly promote the growth of Haematococcus pluvialis, resulting in higher astaxanthin yields. To explore the mechanism of γ-aminobutyric acid induced increase of biomass and astaxanthin production in Haematococcus pluvialis, we conducted both transcriptome and metabolome analyses. The results suggest that the plant hormone signal pathway played a regulatory role in the algae cells, with the genes related to stress resistance being up-regulated. The expression of RuBisco in carbon fixation pathway was also up-regulated, which improved the utilization efficiency of carbon dioxide and biomass under the high light irradiation. Under high light stress, the expression of Lhca2 was up-regulated, and the expression of PTOX related to light protection was up-regulated, while the expression of genes related to astaxanthin synthesis was down-regulated, showing that γ-aminobutyric acid enhanced the photo-protection and stress resistance. Furthermore, we measured the pigment contents, showing that γ-aminobutyric acid increased the contents of chlorophyll and carotene under the condition of nutrient deficiency in the late stage of green vegetative growth. The photosynthesis evaluation reveals that the electron transfer rate (ETR) and non-photochemical quenching (NPQ) of algae cells increased with γ-aminobutyric acid treatment, confirming that γ-aminobutyric acid enhanced the heat dissipation capacity and reduced the light damage. As such, we have demonstrated that exogenous γ-aminobutyric acid can effectively promote the growth of algae cells and increase the biomass and astaxanthin production through the mechanism of improving the stress resistance and photo-protection ability of Haematococcus pluvialis.
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Transcriptomic and metabolic analysis of an astaxanthin-hyperproducing Haematococcus pluvialis mutant obtained by low-temperature plasma (LTP) mutagenesis under high light irradiation
Algal Research, 2020Co-Authors: Zhu Chen, Jun Chen, Jinghua Liu, Song Qin, Qing HuangAbstract:Abstract Haematococcus pluvialis can accumulate sufficient levels of astaxanthin under various stress conditions. High light irradiation is essential for astaxanthin accumulation in Haematococcus pluvialis. However, a lack of genomic information limits the understanding of its physiological metabolism for high astaxanthin production. In this work, we investigated the wild-type (WT) strain and mutant strain (named as M3 which was obtained in our previous work) under high light irradiation and compared the difference in astaxanthin biosynthesis. We collected and analyzed the data of de novo transcriptome information of Haematococcus pluvialis at 24 h under high light stress. Our transcriptomic results indicated that M3 strain had higher utilization efficiency of CO2 to provide the precursors of carotenoid and fatty acid biosynthesis by increasing the expression levels of phosphoenolpyruvate carboxylase (PEPC), malate dehydrogenase (MDH), malate dehydrogenase (ME), ribulose bisphosphate carboxylase/oxygenase (Rubisco) activase (RCA) and glyceraldehyde 3-phosphate dehydrogenase (GAPDH) while decreasing the expression levels of fructose-1, 6-bisphosphatase (FBP). The analysis of pigments, chlorophyll fluorescence and the quantitative real-time polymerase chain reaction (qRT-PCR) analysis revealed that M3 strain maintained higher photosynthetic activity by regulating chlororespiration pathway and elevating non-photosynthetic pigment (lutein, β-carotene, and astaxanthin) content to alleviate photooxidative damage. Moreover, the M3 strain showed higher fatty acid content than the WT strain. Overall, combinative analysis of de novo transcriptomic and physiological data provided information necessary for not only a better understanding of the difference in astaxanthin biosynthesis between WT and M3 strains but also the feasibility of genetic engineering of Haematococcus pluvialis in the future.
Xiangzhao Mao - One of the best experts on this subject based on the ideXlab platform.
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Effective Astaxanthin Extraction from Wet Haematococcus pluvialis Using Switchable Hydrophilicity Solvents
ACS Sustainable Chemistry & Engineering, 2018Co-Authors: Wen-can Huang, Hui Liu, Weiwei Sun, Changhu Xue, Xiangzhao MaoAbstract:A novel approach based on switchable hydrophilicity solvents (SHS) was developed for extracting astaxanthin from wet microalgae. Dimethylaminocyclohexane (DMCHA) was used to extract astaxanthin from wet Haematococcus pluvialis, and the extraction efficiency reached 87.2%. Astaxanthin was recovered from the DMCHA without distillation by simply adding H2O and CO2.
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Effective Astaxanthin Extraction from Wet Haematococcus pluvialis Using Switchable Hydrophilicity Solvents
2018Co-Authors: Wen-can Huang, Hui Liu, Weiwei Sun, Changhu Xue, Xiangzhao MaoAbstract:A novel approach based on switchable hydrophilicity solvents (SHS) was developed for extracting astaxanthin from wet microalgae. Dimethylaminocyclohexane (DMCHA) was used to extract astaxanthin from wet Haematococcus pluvialis, and the extraction efficiency reached 87.2%. Astaxanthin was recovered from the DMCHA without distillation by simply adding H2O and CO2
Jian-ping Yuan - One of the best experts on this subject based on the ideXlab platform.
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Indirect photometric ion chromatographic analysis of anions in Haematococcus pluvialis culture media
Biotechnology Letters, 2001Co-Authors: Jian-ping Yuan, Feng ChenAbstract:An indirect photometric ion chromatographic method for the simultaneous determination of chloride, nitrate and sulfate ions was developed and applied to the determination of anions, mainly nitrate, in the alga Haematococcus pluvialis culture media. Using phthalic acid/sodium tetraborate aqueous solution as the mobile phase, anions can be detected indirectly by a UV detector. The calibration curves for these anions gave good linearity from 1 to 1000 μg ml−1.
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Purification of trans-astaxanthin from a high-yielding astaxanthin ester-producing strain of the microalga Haematococcus pluvialis
Food Chemistry, 2000Co-Authors: Jian-ping Yuan, Feng ChenAbstract:The purification method including extraction, saponification, and separation was established for preparing free trans-astaxanthin from a high-yielding astaxanthin ester-producing strain of the microalga Haematococcus pluvialis which contained 3.67% trans-astaxanthins and 1.35% cis-astaxanthins of the dry cells. Low temperature (5°C) was chosen to minimize the degradation of astaxanthins during saponification, and 94.4% free trans-astaxanthin was obtained from trans-astaxanthin esters after 12 h of saponification. With this method, 32.2 mg trans-astaxanthin was obtained from 1 g dry algal cells. In addition, a new gradient reversed-phase HPLC method, suited for the quick analysis of free astaxanthins and astaxanthin esters in the unsaponified and saponified pigment extracts from the high-yielding astaxanthin ester-producing strain of the microalga Haematococcus pluvialis, was developed and applied to the determination of astaxanthin contents during the processes of extraction, saponification, and purification.
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Chromatographic separation and purification of trans-astaxanthin from the extracts of Haematococcus pluvialis
Journal of Agricultural and Food Chemistry, 1998Co-Authors: Jian-ping Yuan, Feng ChenAbstract:A gradient reversed-phase HPLC method was developed for the separation of astaxanthin esters and the isomers of astaxanthin from the unsaponified and saponified pigment extracts of the microalga Haematococcus pluvialis. Four kinds of isomers of astaxanthin and astaxanthin esters, (3S,3‘S)-trans-astaxanthin, (3S,3‘S)-9-cis-astaxanthin, (3S,3‘S)-13-cis-astaxanthin, (3R,3‘R)-trans-astaxanthin, and their esters, were separated and identified. A small amount of (3S,3‘S)-15-cis-astaxanthin was also detected from the saponified extract. In addition, a chromatographic purification method was established for the preparation of natural trans-astaxanthin from the saponified extract of H. pluvialis. With this method, 3.7 mg of astaxanthin was isolated from 1 g of dry biomass of H. pluvialis. The purified astaxanthin contained approximately 97.7% trans-astaxanthin, 1.1% cis-astaxanthin, and 1.2% impurity. Keywords: Astaxanthin; astaxanthin esters; purification; carotenoids; Haematococcus pluvialis; HPLC
Zhu Chen - One of the best experts on this subject based on the ideXlab platform.
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Exogenous γ-aminobutyric acid promotes biomass and astaxanthin production in Haematococcus pluvialis
Algal Research, 2020Co-Authors: Zhu Chen, Qing HuangAbstract:Abstract Haematococcus pluvialis is one of most efficient organisms of producing astaxanthin. To achieve high astaxanthin yield, one strategy in the microalgae industry is to promote growth and biomass of Haematococcus pluvialis. For this purpose, we applied γ-aminobutyric acid (GABA) in the cultivation system and found it could significantly promote the growth of Haematococcus pluvialis, resulting in higher astaxanthin yields. To explore the mechanism of γ-aminobutyric acid induced increase of biomass and astaxanthin production in Haematococcus pluvialis, we conducted both transcriptome and metabolome analyses. The results suggest that the plant hormone signal pathway played a regulatory role in the algae cells, with the genes related to stress resistance being up-regulated. The expression of RuBisco in carbon fixation pathway was also up-regulated, which improved the utilization efficiency of carbon dioxide and biomass under the high light irradiation. Under high light stress, the expression of Lhca2 was up-regulated, and the expression of PTOX related to light protection was up-regulated, while the expression of genes related to astaxanthin synthesis was down-regulated, showing that γ-aminobutyric acid enhanced the photo-protection and stress resistance. Furthermore, we measured the pigment contents, showing that γ-aminobutyric acid increased the contents of chlorophyll and carotene under the condition of nutrient deficiency in the late stage of green vegetative growth. The photosynthesis evaluation reveals that the electron transfer rate (ETR) and non-photochemical quenching (NPQ) of algae cells increased with γ-aminobutyric acid treatment, confirming that γ-aminobutyric acid enhanced the heat dissipation capacity and reduced the light damage. As such, we have demonstrated that exogenous γ-aminobutyric acid can effectively promote the growth of algae cells and increase the biomass and astaxanthin production through the mechanism of improving the stress resistance and photo-protection ability of Haematococcus pluvialis.
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Transcriptomic and metabolic analysis of an astaxanthin-hyperproducing Haematococcus pluvialis mutant obtained by low-temperature plasma (LTP) mutagenesis under high light irradiation
Algal Research, 2020Co-Authors: Zhu Chen, Jun Chen, Jinghua Liu, Song Qin, Qing HuangAbstract:Abstract Haematococcus pluvialis can accumulate sufficient levels of astaxanthin under various stress conditions. High light irradiation is essential for astaxanthin accumulation in Haematococcus pluvialis. However, a lack of genomic information limits the understanding of its physiological metabolism for high astaxanthin production. In this work, we investigated the wild-type (WT) strain and mutant strain (named as M3 which was obtained in our previous work) under high light irradiation and compared the difference in astaxanthin biosynthesis. We collected and analyzed the data of de novo transcriptome information of Haematococcus pluvialis at 24 h under high light stress. Our transcriptomic results indicated that M3 strain had higher utilization efficiency of CO2 to provide the precursors of carotenoid and fatty acid biosynthesis by increasing the expression levels of phosphoenolpyruvate carboxylase (PEPC), malate dehydrogenase (MDH), malate dehydrogenase (ME), ribulose bisphosphate carboxylase/oxygenase (Rubisco) activase (RCA) and glyceraldehyde 3-phosphate dehydrogenase (GAPDH) while decreasing the expression levels of fructose-1, 6-bisphosphatase (FBP). The analysis of pigments, chlorophyll fluorescence and the quantitative real-time polymerase chain reaction (qRT-PCR) analysis revealed that M3 strain maintained higher photosynthetic activity by regulating chlororespiration pathway and elevating non-photosynthetic pigment (lutein, β-carotene, and astaxanthin) content to alleviate photooxidative damage. Moreover, the M3 strain showed higher fatty acid content than the WT strain. Overall, combinative analysis of de novo transcriptomic and physiological data provided information necessary for not only a better understanding of the difference in astaxanthin biosynthesis between WT and M3 strains but also the feasibility of genetic engineering of Haematococcus pluvialis in the future.
