Showing papers on "Chlorococcum published in 2001"
TL;DR: In this article, free trans- astaxanthin accumulated in the alga Chlorococcum sp. was markedly enhanced from 3.664 mg g −1 cell dry weight to 5.724 mgg −1cell dry weight when the culture was supplemented with hydrogen peroxide (0.1 mM).
67 citations
TL;DR: Prepative high-speed counter-current chromatography with a two-phase solvent system composed of n-hexane-ethyl acetate-ethanol-water was successfully performed yielding astaxanthin at 97% purity from 250 mg of the crude extract in a one-step separation.
65 citations
TL;DR: The developed two-step process provides a feasible strategy for commercial production of ketocarotenoids by the green microalga, Chlorococcum sp.
Abstract: The production of ketocarotenoids (KCs) from Chlorococcum sp. strain MA-1was investigated by a two-step process. In the first step, 18 g biomass l–1 was achieved by feeding glucose to the heterotrophic cultures; in the second step, the high-density cultures were treated with light illumination or chemical stress in dark, respectively, to induce KC synthesis. Light-treated cultures could produce 103 mg total KCs l–1 and 32 mg astaxanthin l–1, three times higher than those from chemical-treated cultures, in the 10 days of induction. The percentages of individual KCs (hydroxyechinenone, canthaxanthin, adonirubin and astaxanthin) in the total KCs were not markedly influenced by the different stress conditions. The developed two-step process provides a feasible strategy for commercial production of ketocarotenoids by the green microalga, Chlorococcum sp. strain MA-1.
52 citations
TL;DR: KI (1 mM) inhibited the enhancement of carotenogenesis by superoxide anion radicals (O2−), with a decrease of astaxanthin formation to 1.7 mg g−1 cell dry wt, which suggested that O2− might be transformed to OH• before promoting carOTenogenesis in Chlorococcum sp.
Abstract: The induction of astaxanthin formation by reactive oxygen species in mixotrophic culture of Chlorococcum sp was investigated H2O2 (01 mM) enhanced the total astaxanthin formation from 58 to 65 mg g−1 cell dry wt Fe2+ (05 mM) added to the medium with H2O2 (01 mM) further promoted astaxanthin formation to 71 mg g−1 cell dry wt Similarly, Fe2+ (05 mM) together with methyl viologen (001 mM) promoted astaxanthin formation to 63 mg g−1 cell dry wt In contrast, an addition of KI (1 mM), a specific scavenger for hydroxyl radicals (OH•), together with H2O2 (01 mM) and Fe2+ (05 mM), to the medium decreased astaxanthin formation to 18 mg g−1 cell dry wt KI (1 mM) also inhibited the enhancement of carotenogenesis by superoxide anion radicals (O2
−), with a decrease of astaxanthin formation to 17 mg g−1 cell dry wt This suggested that O2
− might be transformed to OH• before promoting carotenogenesis in Chlorococcum sp
29 citations
TL;DR: The study showed that C. vulgaris, S. quadricauda and Chlorococcum sp.
Abstract: The effect of ten microalgal chlorophytes isolated from mosquito breeding containers on the survival, larval development and adult body size of the mosquito Aedes aegypti was investigated. All larvae fed with six of the microalgal isolates died after 7 days. These isolates were found to be resistant to digestion by mosquito larvae. Delayed pupation and body size reduction of the mosquitos fed with Chlorococcum UMACC 218 and Scenedesmus UMACC 220 were observed. In contrast, larvae fed with Ankistrodesmus convolutus UMACC 101 and Chlorococcum UMACC 213 were bigger in size than those fed with normal insectory feed. The present study showed that microalgal chlorophytes have the potential to be used as larvicidal agents for mosquitos.
28 citations
Book•
01 Jan 2001
TL;DR: This work presents a meta-analyses of the phytochemical properties of polyunsaturated Fatty Acids and its applications in microalgae and Microalgae-like Organisms, and investigates their role in the regulation of Carbon Metabolism in Cyanobacteria.
Abstract: Preface. 1. Polyunsaturated Fatty Acids: Biological Significance, Biosynthesis, and Production by Microalgae and Microalgae-like Organisms C.Y. Yap, F. Chen. 2. Application of Statistically-Based Experimental Designs for Optimizing Eicosapentaenoic Acid Production by Nitzschia laevis Z.Y. Wen, F. Chen. 3. Optimization of Nitrogen Sources for the Production of Eicosapentaenoic Acid by the Diatom Nitzschia laevis in Heterotrophic Cultures Z.Y. Wen, F. Chen. 4. Effects of Nitrogen Source and Vitamin B12 on Docosahexaenoic Acid Production by Crypthecodinium cohnii Y. Jiang, et al. 5. Neural Networks for Modelling and Predicting the Chlorella protothecoides Cultivation Processes G.Y. Zhang, et al. 6. Modelling of a Continuous Algal Production System Using Intelligent Methods N. Clarkson, et al. 7. High Yield Production of Lutein by Heterotrophic Chlorella protothecoides in Fed-Batch Systems X.M. Shi, F. Chen. 8. Induction of Astaxanthin Formation in the Green Microalga Chlorococcum sp. by Reactive Oxygen Species (ROS) under Mixotrophic Conditions of Growth R.Y.N. Ma, F. Chen. 9. Preparative Isolation and Purification of Astaxanthin from the Green Microalga Chlorococcum sp. by High-Speed Counter-Current Chromatography H.B. Li, F. Chen. 10. Changes in Content, Constituents and Distribution of Constitutive and Excreted Sugars of Spirulina (Arthrospira) maxima in Nutrient-Limited Batch Cultures J.L. Xia, et al. 11. Growth, Nutrient Assimilation and Cadmium Removal by Suspended and Immobilized Scenedesmus acutus Cultures: Influence of Immobilization Matrix R.O. Canizares-Villanueva, et al. 12. Metal Sorption by Microalgae for Employment in Biotreatment of Environmental Heavy Metal Contamination P. Mathad, et al. 13. Toxic Effect of Tributyltin (TBT) on Different Green Microalgal Species N.F.Y. Tam, et al. 14. Catalytic Degradation of the Herbicide Glyphosate by the Paddy Field Isolates of Cyanobacteria T. Balakumar, V. Ravi. 15. Effect of Post-Collection Storage Time and Season on the Antibacterial Activity of Selected Southern African Marine Macroalgae V. Vlachos, et al. 16. Hormesis in Bioassay of Macroalgal Fundal Propagules M. Barreto, et al. 17. Biological Activities of Extracts from Several Species of Rohdomelaceae from Fujian Coasts of China Y. Zheng. 18. Studies of the Pharmacology and Toxicology of Spirulina maxima (SMNJU.02) Z.L. Liu, D.H. Cao. 19. Characterization of the icfG Gene Cluster Implicated in the Regulation of Carbon Metabolism in the Cyanobacterium Synechocystis sp. PCC 6803 L. Gonzalez, et al. 20. Preliminary Studies on the Genetic Transformation of Spirulina platensis X.C. Zhang, et al. 21. Effect of Temperature on the Desaturase Gene Translation in Spirulina platensis Strain C1 A. Hongsthong, et al. 22. Application of a Telemetry System to Studying Microalgal Dynamics and Red Tides in Hong Kong I.H.Y. Lam, I.J. Hodgkiss. 23. The Pitfalls of Using Different Classification Systems to Quantify Biodiversity of Cyanobacteria: A Case Study from Hong Kong Rocky Shores S. Nagarkar. Index.
4 citations
01 Jan 2001
TL;DR: The induction of astaxanthin formation by reactive oxygen species in mixotrophic culture of Chlorococcum sp.
Abstract: The induction of astaxanthin formation by reactive oxygen species in mixotrophic culture of Chlorococcum sp. was investigated. H2O2 (0.1 mM) enhanced the total astaxanthin formation from 5.8 to 6.5 mg/g cell dry weight Fe2+ (0.5 mM) added to the medium with H2O2 (0.1 mM) further promoted astaxanthin formation to 7.1 mg/g cell dry weight Similarly, Fe (0.5 mM) together with methyl viologen (0.01 mM) promoted astaxanthin formation to 6.3 mg/g cell dry weight In contrast, an addition of KI (1 mM), a specific scavenger for hydroxyl radicals (OH•), together with H2O2 (0.1 mM) and Fe2+ (0.5 mM), to the medium decreased astaxanthin formation to 1.8 mg/g cell dry weight KI (1 mM) also inhibited the enhancement of carotenogenesis by superoxide anion radicals (O2 -), with a decrease of astaxanthin formation to 1.7 mg/g cell dry weight. This suggested that O2 - might be transformed to OH• before promoting carotenogenesis in Chlorococcum sp.
3 citations
TL;DR: It was found that a dioxygenase cofactor mixture of Fe2+, ascorbic acid and 2-oxoglutarate was required to the carotenogenic activities and oxygen was essential for the conversions.
2 citations