Rapid detection of heterotrophic growth of Haematococcus pluvialis using indirect conductimetry

An indirect conductimetric method was developed for the rapid detection of heterotrophic growth of Haematococcus pluvialis. Selective HKU medium was superior to Whitley Impedance Broth. Acetate was better than glucose not only for the biomass production (30,200 cells ml on 1 g acetate l vs. 14,800 cells ml on 1 g glucose l ) but also for the time needed to detect significant growth (10.9 h on 1 g acetate l vs. 36.9 h on 1 g glucose l ). The largest maximum conductance change of -1455 S and the shortest detection time of 10.9 h were found in HKU medium containing 1 g acetate l , and the cell concentration increased by 5.5 times after 4 days of cultivation.     

雨生红球藻虾青素合成研究进展

虾青素是一种重要的次级类胡萝卜素,具有高活性的抗氧化功能,广泛应用于食品保健、医药、水产养殖等领域。雨生红球藻是一种在胁迫条件下能够大量积累虾青素的微藻。文中回顾了雨生红球藻虾青素的生物合成研究的进展,包括虾青素生物合成的诱导与调控、虾青素合成与光合作用及脂类代谢的关系等研究现状。     

Vitamine als vermehrungsbegrenzende Faktoren bei Haematococcus pluvialis

Zusammenfassung Es wird gezeigt, daß die Vermehrung allein von dem zur Verfügung stehenden Vitamin beeinflußt wird. Ist dieses verbraucht, dann kann nur ein neuerlicher Vitaminzusatz die Vermehrung wieder ansteigen lassen. Ein weiterer Zusatz von Nährsalzen hat keine Wirkung.     

Gene expression profile analysis in astaxanthin-induced Haematococcus pluvialis using a cDNA microarray

The unicellular green alga Haematococcus pluvialis (Volvocales) is known for the ketocarotenoid astaxanthin (3, 3′-dihydroxy-β, β-carotene-4, 4′-dione) accumulation, which is induced under unfavorable culture conditions. In this work, we used cDNA microarray analysis to screen differentially expressed genes in H. pluvialis under astaxanthin-inductive culture conditions, such as combination of cell exposure to high irradiance and nutrient deprivation. Among the 965 genes in the cDNA array, there are 144 genes exhibiting differential expression (twofold changes) under these conditions. A significant decrease in the expression of photosynthesis-related genes was shown in astaxanthin-accumulating cells (red cells). Defense- or stress-related genes and signal transduction genes were also induced in the red cells. A comparison of microarray and real-time PCR analysis showed good correlation between the differentially expressed genes by the two methods. Our results indicate that the cDNA microarray approach, as employed in this work, can be relied upon and used to monitor gene expression profiles in H. pluvialis. In addition, the genes that were differentially expressed during astaxanthin induction are suitable candidates for further study and can be used as tools for dissecting the molecular mechanism of this unique pigment accumulation process in the green alga H. pluvialis. Electronic Supplementary Material Supplementary material is available for this article at and is accessible for authorized users.     

雨生红球藻的光周期效应

雨生红球藻(Haematococcus pluvialis)是一种单细胞淡水绿藻, 是自然界已知的中虾青素含量最高的生物物种。通过分析3种光照强度(70、120和300 μmol·m^–2·s^–1)下雨生红球藻细胞形态、生长速率和虾青素含量的差异, 对其光周期效应进行了研究。结果表明, 不同光强下适宜雨生红球藻生长的光周期均为16小时光照/8小时黑暗, 光强为120 μmol·m^–2·s^–1时其细胞生长速率最大, 为0.43 d^–1; 细胞内虾青素含量随着光强和光照时间的增加而增加, 在300 μmol·m^–2·s^–1光强下连续光照15天后, 藻细胞呈亮红色, 平均直径为21.02 μm, 最大虾青素值达39.40 pg·cell^–1。     

Some factors governing encystment in Haematococcus pluvialis

Zusammenfassung Die Ergebnisse zeigen, daß die Dauersporenbildung bei dem Flagellaten Haematococcus pluvialis in Kultur durch Störung der Vermehrung bewirkt wird, falls diese nicht eine Folge mangelnder Kohlenstoffassimilation ist. Es hat sich erwiesen, daß anhaltende Assimilation für die Bildung der Dauersporen notwendig ist, ja, daß der Kohlenstoffbedarf dabei größer ist als für bloße Vermehrung.     

城市生活污水用于培养雨生红球藻的研究

虾青素是自然界广泛存在的一种橘红色类胡萝卜素,广泛应用于食品、药品和化妆品行业。在虾青素的制备中,雨生红球藻是生产虾青素的最有效来源,目前提高虾青素产量的方式主要为提高生物量和产物合成率。目前已有大量研究针对生物量的优化,但依然存在改善空间。为此,尝试用城市生活污水作为培养基对雨生红球藻进行培养。结果表明,生活污水能促进雨生红球藻的生长,其产量是现有BG11培养基的2倍;虾青素的合成时期显著提前（P<0.05）,且体内重金属含量未明显富集,处在安全浓度范围。此外,养藻后的城市生活污水中氮、磷含量显著降低（P<0.05）,高氮、磷富余的情形得到有效改善。证实利用污水培养雨生红球藻的双重效应,一方面有利于积累藻类生物量,另一方面有助于净化水质,在经济效益和生态效益上具有极好的发展潜力。     

雨生红球藻混合营养与异养培养研究

研究雨生红球藻混合营养生长与异养生长对碳源及碳源浓度的需求,并对两种生长型进行比较。结果表明,乙酸钠较葡萄糖等碳源更能维持红球藻进行混合营养民异养生长。红球藻混合营养型生长与异养型生长的适宜乙酸钠浓度范围分别是０．５￣１．０ｇ／Ｌ和１￣１．５ｇ／Ｌ。混合营养型及异养型的平均速率分别是０．７２ｄ＾－１和０．５３ｄ＾－１,培养８ｄ的细胞干重分别是０．６５ｇ／Ｌ和０．３２ｇ／Ｌ。与光养型（对照）相比,混     

Oxidative stress modulates astaxanthin synthesis in Haematococcus pluvialis

Journal of Applied Phycology - Astaxanthin, a carotenoid with potent antioxidant effects, is produced by the green alga Haematococcus pluvialis in response to stressful environmental conditions....     

Commercial production of astaxanthin from Haematococcus pluvialis using 25,000-liter outdoor photobioreactors

Recent developments in photobioreactor technology havemade the production of astaxanthin from Haematococcus pluvialis commercially viable. The coreof our astaxanthin production chain is the AquasearchGrowth Module (AGM), a 25,000 L enclosed andcomputerized outdoor photobioreactor.At Aquasearch's newly expanded facility (dedicatedJanuary 1999), three AGMs (total volume 75,000 L) areused to produce large amounts of clean, fast growing,H. pluvialis. The H. pluvialis biomassproduced in the AGMs is transferred daily to a pondculture system, where carotenogenesis and astaxanthinaccumulation are induced. Following a 5-dayinduction period, the reddened H. pluvialiscells are harvested by gravitational settling. Theharvested biomass, which averages > 2.5 astaxanthinas percent of the dry weight, is transferred to aprocessing building where a high pressure homogenizeris used to rupture the cells' walls. Once the biomasshas been homogenized, it is dried to less than 5%moisture utilizing proprietary drying technology. Thedried product is then ready to be packaged accordingto customer needs.The photobioreactor research program has almostdoubled the performance of the AGMs in the first ninemonths of operations: standing biomass concentrationincreased from 50 to 90 g m^-2 and productionincreased from 9 to 13 g m^-2 d^-1 during thisperiod. Here, we discuss the significance of thesechanges in production parameters to the viability ofcommercial production of astaxanthin and other highvalue products from microalgae.     

雨生红球藻中虾青素的研究与应用

雨生红球藻是单细胞微藻,其中的虾青素具有抗氧化、抗肿瘤、预防心脑血管疾病等多种生物活性,在食品、医药、保健品、化妆品及养殖业有诸多用途。概述了雨生红球藻虾青素含量影响因素,雨生红球藻培养方法、虾青素的提取方法及其应用领域等最新研究成果,为虾青素的开发利用提供帮助。     

雨生红球藻(Haematococcus pluvialis)的光谱特性研究

实验测定了雨生红球藻不同生长阶段的色素组成,吸收光谱,荧光光谱,并对其进行了分析。结果表明,用490nm波长激发时,雨生红球藻在绿色细胞阶段存在710nm和730nm附近的长波长荧光发射峰,而在红色细胞阶段仅存在730nm的长波长荧光发射峰,预示着雨生红球藻不同生长阶段在PSⅠ结构,组成,及其色素蛋白的排布等方面有很大差异。     

Carotenoid accumulation in Haematococcus pluvialis in mixotrophic growth

The microalga Haematococcus pluvialis was cultured with NaNO₃ from 0 to 1 g l^–1 and optimal growth was obtained at 0.15 g l^–1. Sodium acetate and malonate (from 0 to 2% w/v) enhanced the accumulation of astaxanthin three and five times higher, respectively, than in autotrophic control cultures. However, high concentration of those compounds strongly inhibited growth. The ratio chlorophyll a/total carotenoids was a good indicator of the extent of nitrogen deficiency in the cells.     

Characterization of carotenoid hydroxylase gene promoter in Haematococcus pluvialis

Astaxanthin, a high-value ketocarotenoid is mainly used in fish aquaculture. It also has potential in human health due to its higher antioxidant capacity than beta-carotene and vitamin E. The unicellular green alga Haematococcus pluvialis is known to accumulate astaxanthin in response to environmental stresses, such as high light intensity and salt stress. Carotenoid hydroxylase plays a key role in astaxanthin biosynthesis in H. pluvialis. In this paper, we report the characterization of a promoter-like region (-378 to -22 bp) of carotenoid hydroxylase gene by cloning, sequence analysis and functional verification of its 919 bp 5'-flanking region in H. pluvialis. The 5'-flanking region was characterized using micro-particle bombardment method and transient expression of LacZ reporter gene. Results of sequence analysis showed that the 5'-flanking region might have putative cis-acting elements, such as ABA (abscisic acid)-responsive element (ABRE), C-repeat/dehydration responsive element (C-repeat/DRE), ethylene-responsive element (ERE), heat-shock element (HSE), wound-responsive element (WUN-motif), gibberellin-responsive element (P-box), MYB-binding site (MBS) etc., except for typical TATA and CCAAT boxes. Results of 5' deletions construct and beta-galactosidase assays revealed that a highest promoter-like region might exist from -378 to -22 bp and some negative regulatory elements might lie in the region from -919 to -378 bp. Results of site-directed mutagenesis of a putative C-repeat/DRE and an ABRE-like motif in the promoter-like region (-378 to -22 bp) indicated that the putative C-repeat/DRE and ABRE-like motif might be important for expression of carotenoid hydroxylase gene.     

雨生红球藻中IPP异构酶基因的系统发育分析

通过系统进化树的构建对IPP异构酶的系统发育进行分析研究。结果表明,不同来源的IPP异构酶基因均是单系分支,并且各个分支有着不同进化模式;似然比分析结果发现,绿藻来源的IPP异构酶有9．8％的氨基酸位点经受了正选择的压力,其基因的进化模式不同于高等植物和细菌中的IPP异构酶基因。     

不同激光对雨生红球藻的刺激效应

本文研究了Ｈｅ－Ｎｅ激光和半导体激光对生产虾青素的雨生红球藻（Ｈａｅｍａｔｏｃｏｃｃｕｓ ｐｌｕｖｉａｌｉｓ）的生理刺激作用。对两种激光不同辐照剂量的生长刺激作用,叶绿素含量及虾青素累积速率的变化进行了比较。实验结果表明,低功率的红色激光对红球藻营养细胞的增殖具有明显的促进作用。     

Time- and media-dependent secondary carotenoid accumulation in Haematococcus pluvialis

The green microalgae Haematococcus pluvialis synthesizes secondary carotenoids after exposure to environmental stress, a process that is used for the biotechnological production of astaxanthin (Ax). This study reports, for the first time, the medium-dependent changes in the carotenoid pattern throughout the cultivation process as well as the exact composition of carotenoids and their fatty acid mono- and diesters using LC-MS. Secondary carotenoid formation started immediately upon exposure to nutrient depletion and high light conditions. Ax and its corresponding mono- and diesters were detected simultaneously. After 15 days of cultivation, no significant changes were detected in carotenoid composition; however, the ratio between carotenoid mono- and diesters still varied. Main carotenoids were identified as Ax linolenate and Ax oleate, but also five adonirubin and one lutein monoester were detected. The influence of three different autotroph media was studied on carotenoid content, which reached a maximum 16.1 mg/g dry weight. The results indicate that media composition has an influence on the ratio of Ax mono- to diester but not on the qualitative composition of secondary carotenoids in H. pluvialis. Beside the pathway via echinenone, canthaxanthin and adonirubin the results indicate that Ax biosynthesis takes place via another route: from beta-carotene via beta-cryptoxanthin, zeaxanthin and adonixanthin.