共查询到20条相似文献,搜索用时 616 毫秒
1.
2.
3.
Isolation and characterization of a carotenoid oxygenase gene from Chlorella zofingiensis (Chlorophyta) 总被引:1,自引:0,他引:1
The green alga Chlorella zofingiensis produces large amounts of the valuable ketocarotenoid astaxanthin under dark, heterotrophic growth conditions, making it potentially employable for commercial production of astaxanthin as feed additives, colorants, and health products. Here, we report the identification and characterization of a β-carotene oxygenase (CRTO) gene that is directly involved in the biosynthesis of ketocarotenoids in C. zofingiensis. The open reading frame of the crtO gene, which is interrupted by three introns of 243, 318, and 351 bp, respectively, encodes a polypeptide of 312 amino acid residues. Only one crtO gene was detected in the genome of C. zofingiensis. Furthermore, the expression of the crtO gene was transiently up-regulated upon glucose treatment. Functional complementation in Escherichia coli showed that the coding protein of the crtO gene not only exhibits normal CRTO activity by converting β-carotene to canthaxanthin via echinenone, but also displays a high enzymatic activity of converting zeaxanthin to astaxanthin via adonixanthin. Based on the bifunctional CRTO, a predicted pathway for astaxanthin biosynthesis in C. zofingiensis is described, and the CRTO is termed as carotenoid 4,4′-β-ionone ring oxygenase. 相似文献
4.
Production and analysis of secondary carotenoids in green algae 总被引:6,自引:0,他引:6
The microalgae Neochloris wimmeri, Scenedesmus vacuolatus, Scotiellopsisoocystiformis, Chlorella zofingiensis and Protosiphon botryoides were grown under secondarycarotenoid inductive conditions. The results indicatethat nitrogen deficiency and high light intensity arepotential inducers of astaxanthin formation in thefive microalgae studied. All these microalgaeaccumulate significant quantities of secondarycarotenoids, mainly as astaxanthin esters andcanthaxanthin. They also showed high resistance toenvironmental conditions. All these qualities makethese microalgae good candidates for successfulculture in open ponds. 相似文献
5.
A new paradigm for producing astaxanthin from the unicellular green alga Haematococcus pluvialis 下载免费PDF全文
Zhen Zhang Baobei Wang Qiang Hu Milton Sommerfeld Yuanguang Li Danxiang Han 《Biotechnology and bioengineering》2016,113(10):2088-2099
6.
Accumulation of astaxanthin and lutein in<Emphasis Type="Italic"> Chlorella zofingiensis</Emphasis> (Chlorophyta) 总被引:6,自引:0,他引:6
Del Campo JA Rodríguez H Moreno J Vargas MA Rivas J Guerrero MG 《Applied microbiology and biotechnology》2004,64(6):848-854
When grown photoautotrophically, Chlorella zofingiensis strain CCAP 211/14 accumulates a significant amount of valuable carotenoids, namely astaxanthin and lutein, of increasing demand for use as feed additives in fish and poultry farming, as colorants in food, and in health care products. Under standard batch-culture conditions, this microalgal strain exhibits high values of both growth rate (about 0.04 h–1) and standing cell population (over 1011 cells l–1, or 7 g dry weight l–1). Lutein, in a free (unesterified) form, was the prevalent carotenoid during early stages of cultivation (over 0.3 pg cell–1, equal to 4 mg g–1 dry weight, or 20 mg l–1 culture), whereas esterified astaxanthin accumulated progressively, to reach a maximum (over 0.1 pg cell–1, equal to 1.5 mg g–1 dry weight, or 15 mg l–1 culture) in the late stationary phase. A differential response of lutein and astaxanthin accumulation was also recorded with regard to the action of some environmental and nutritional factors. C. zofingiensis CCAP 211/14 represents a unique model system for analyzing the differential regulation of the levels of primary (lutein) and secondary (astaxanthin) carotenoids. Relevant also from the biotechnological viewpoint, this photosynthetic organism, with outstanding attributes for fast photosynthetic growth and carotenoid accumulation, might prove most valuable for its application to the mass production of either or both lutein and astaxanthin. 相似文献
7.
Comparison of the accumulation of astaxanthin in Haematococcus pluvialis and other green microalgae under N-starvation and high light conditions 总被引:3,自引:0,他引:3
Haematococcus pluvialis gave the highest astaxanthin accumulation rate (2.7 mg l–1 day–1) and total astaxanthin content ( 22.7 mg g–1 biomass). Astaxanthin accumulation in Neochloris wimmeri, Protosiphon botryoides, Scotiellopsis oocystiformis, Chorella zofingiensis and Scenedesmus vacuolatus was, respectively, 19.2, 14.3, 10.9, 6.8 and 2.7 mg astaxanthin g–1 biomass, respectively. 相似文献
8.
Ngoc-Phuong Tran Jae-Kweon Park Z-Hun Kim Choul-Gyun Lee 《Biotechnology and Bioprocess Engineering》2009,14(3):322-329
Astaxanthin production is commonly induced under stress conditions such as nutrient deficiency (N or P), high light stress,
and variations of temperature, high NaCl concentrations, and other factors. The objective of the present study is the analysis
of the effect of oxidative stress by sodium orthovanadate (SOV), a nonspecific inhibitor of protein tyrosine phosphatases,
on the cells growth and astaxanthin production of H. lacustris. In the presence of SOV (lower than 5.0 mM), maximum growth of H. lacustris obtained was 2.4 × 105 cells/mL in MBBM medium at 24°C under continuous illumination (40 μE/m2/s) of white fluorescent light, with continuous aeration of CO2 (0.2 vvm). Total carotenoids accumulated per cell biomass unit treated with 2.5 mM SOV has approximately shown 2.5 folds
higher than the control after short period of SOV induction time as 2 days, despite that cells were grown under normal light.
Meanwhile, maximal astaxanthin production from H. lacustris was 10.7 mg/g biomass in MBBM with 5 days of continuous illumination at 40 μE/m2/s, which has been established as optimal light intensity for the control culture of H. lacustris. Treating algae H. lacustris with sodium orthovanadate showed promoting the accumulation of astaxanthin by advancing either the inhibition of dephosphorylation
or synthesis of ATP. Its potential role of PTPases in microalgae H. lacustris is discussed.
The first two authors are equally contributed to this work. 相似文献
9.
The carotenoid composition of the astaxanthin-producing green alga Chlorella zofingiensis was investigated using high-performance liquid chromatography. Astaxanthin, adonixanthin, and zeaxanthin are the major carotenoids
in this alga. The pigment pattern was characterized during the accumulation period, and in response to diphenylamine (DPA),
an inhibitor of carotenoid biosynthesis. An increase in zeaxanthin followed by a decrease in xanthophyll was seen after the
induction of astaxanthin biosynthesis by glucose. This biphasic kinetics of zeaxanthin was parallel to the marked increase
in adonixanthin (from 0 mg g−1 to 0.21 mg g−1) and astaxanthin (from 0.05 mg g−1 to 0.35 mg g−1) and decrease of β-carotene (from 0.30 mg g−1 to 0.03 mg g−1). More importantly, unlike the Haematococcus alga, in which there was a high β-carotene accumulation after DPA treatment, C. zofingiensis showed an accumulation of extra zeaxanthin instead of β-carotene after treatment of the cells with DPA. All these results
observed in vivo studies corroborate the observations in vitro studies at the enzyme level that zeaxanthin is a substrate
for the carotenoid oxygenase in C. zofingiensis. It is suggested that zeaxanthin might be an important intermediate and not an end product of the biosynthetic pathway of
astaxanthin. Therefore, a new pathway for astaxanthin formation by C. zofingiensis, which is different from that of the other astaxanthin-producing microorganisms, is proposed. An understanding of the astaxanthin
biosynthetic pathway may yield important information toward the optimization of astaxanthin production, especially for the
improvement of astaxanthin through genetic manipulations. 相似文献
10.
The green microalga Chlorella zofingiensis can produce the ketocarotenoid astaxanthin under heterotrophic culture conditions. Here we report the growth-associated biosynthesis
of astaxanthin in this biotechnologically important alga. With glucose as sole carbon and energy source, C. zofinginesis grew fast in the dark with rapid exhaustion of nitrogen and carbon sources from media, leading to a high specific growth
rate (0.034 h−1). Cultures started at a cell concentration of about 3.4 × 109 cells l−1 reached, after 6 days, standing biomass values of 1.6 × 1011 cells or 8.5 g dry weight l−1. Surprisingly, the biosynthesis of astaxanthin was found to start at early exponential phase, independent of cessation of
cell division. A general trend was observed that the culture conditions benefiting cell growth also benefited astaxanthin
accumulation, indicating that astaxanthin was a growth-associated product in this alga. The maximum cell dry biomass and astaxanthin
yield were 11.75 g l−1 and 11.14 mg l−1 (about 1 mg g−1), simultaneously obtained in the fed-batch culture with a combined glucose–nitrate mixture addition, which were the highest
ever reported in dark-heterotrophic algal cultures. The possible reasons why dark-heterotrophic C. zofingiensis could produce astaxanthin during the course of cell growth were discussed. 相似文献
11.
12.
Laura Pirastru Mohamed Darwish Fong Lam Chu Fran?ois Perreault Louka Sirois Lekha Sleno Radovan Popovic 《Journal of applied phycology》2012,24(1):117-124
Under stress conditions, some microalgae up-regulate certain biosynthetic pathways, leading to the accumulation of specific
compounds. For example, changing nutrient composition can induce stress in algae’s physiological activities, which may trigger
an intense increase in carotenoid production. In this study, the change of photosynthetic functions and carotenoid production
in the green microalga Scenedesmus sp. was investigated when algal cultures were exposed to conditions including limited nitrogen content with the addition
of sodium acetate. Microalgal cultures were treated for 18 days under higher irradiance conditions. We observed a decrease
of chlorophyll content induced concomitantly with a decline of photosystem II and I photochemistry. At the same time, an important
increase in carotenoid content was detected. By using high-performance liquid chromatographic analysis, we found that the
secondary carotenoids astaxanthin and canthaxanthin were accumulated compared to controls. During the process of carotenoid
accumulation, chlorophyll degradation was found in addition to a strong decrease in photosynthetic electron transport. Such
changes may be associated with the structural reorganization of the photosynthetic apparatus and can be a useful indicator
of secondary carotenoid accumulation in algal cultures. 相似文献
13.
Comparative analysis of astaxanthin and its esters in the mutant E1 of Haematococcus pluvialis and other green algae by HPLC with a C30 column 总被引:1,自引:0,他引:1
Juan Peng WenZhou Xiang QuanMing Tang Ni Sun Feng Chen JianPing Yuan 《中国科学:生命科学英文版》2008,51(12):1108-1115
A gradient reversed-phase high-performance liquid chromatography (HPLC) method using a C30 column was developed for the simultaneous
determination of astaxanthin, astaxanthin monoesters and astaxanthin diesters in the green algae Chlorococcum sp., Chlorella zofingiensis, Haematococcus pluvialis and the mutant E1, which was obtained from the mutagenesis of H. pluvialis by exposure to UV-irradiation and ethyl methanesulphonate (EMS) with subsequent screening using nicotine. The results showed
that the contents of total astaxanthins including free astaxanthin and astaxanthin esters ranged from 1.4 to 30.9 mg/g dry
biomass in these green algae. The lower total astaxanthin levels (< 2 mg/g dry biomass) were detected in the green algae Chlorococcum sp. and C. zofingiensis. The higher total astaxanthin levels (>16 mg/g dry biomass) were found in the green alga H. pluvialis and its mutant E1. It is notable that the mutant E1 is found to have considerably higher amounts of total astaxanthin (30.9
mg/g) as compared to the wild strain of H. pluvialis (16.1 mg/g). This indicates that UV-irradiation and EMS compound mutagenesis with subsequent screening using nicotine is
an effective method for breeding of a high-producing astaxanthin strain of H. pluvialis. In addition, the green alga C. zofingiensis had a remarkably higher percentage of astaxanthin diesters (76.3% of total astaxanthins) and a remarkably lower percentage
of astaxanthin monoesters (18.0% of total astaxanthins) in comparison with H. pluvialis (35.5% for diesters and 60.9% for monoesters), the mutant E1 (49.1% and 48.1%) and Chlorococcum sp. (18.0% and 58.6%).
Supported by the Frontier Research Grant of the SCSIO, the Hundred Talents program of Chinese Academy of Sciences, and National
Natural Sciences of China projects (Grant No. 40776087) 相似文献
14.
Mirash Zhekisheva Aliza Zarka Inna Khozin‐Goldberg Zvi Cohen Sammy Boussiba 《Journal of phycology》2005,41(4):819-826
Under stress conditions, Haematococcus pluvialis Flotow accumulates fatty acid–esterified astaxanthin, in extraplastidial lipid globules. The enhanced accumulation of fatty acids, mainly in triacylglycerols (TAG), among which oleic acid predominates, is linearly correlated with that of astaxanthin. We used inhibitors of either carotenoid or lipid biosynthesis to assess the interrelationship between carotenogenesis and TAG accumulation under high light irradiance as the stress factor. The two carotenogenesis inhibitors used—norflurazon, an inhibitor of phytoene desaturase, and diphenylamine (DPA), an inhibitor of β‐carotene C‐4 oxygenase—suppressed the accumulation of astaxanthin in a concentration‐dependent manner. Concurrently, the accumulation of neutral lipids was significantly less affected. The lipid biosynthesis inhibitor sethoxydim, which inhibits acetyl‐CoA carboxylase, significantly decreased de novo fatty acid synthesis and, in concert, drastically inhibited astaxanthin formation. In the presence of various concentrations of the three inhibitors, the inhibition of astaxanthin was not accompanied by a proportional decrease in oleic acid, which was used as a marker for TAG fatty acids. When astaxanthin synthesis was completely inhibited, the volumetric content of oleic acid was about 60% of the control value when the two carotenogenesis inhibitors (0.05 μM norflurazon or 20 μM DPA) were used and 27% of the control when the lipid‐synthesis inhibitor (50 μM) was used. We suggest therefore that TAG accumulation under high irradiance is not tightly coupled with astaxanthin accumulation, although the correlation between these two processes was demonstrated earlier. Furthermore, we propose that the accumulation of a certain amount of TAG is a prerequisite for the initiation of fatty acid–esterified astaxanthin accumulation in lipid globules. 相似文献
15.
Green cells of Haematococcus pluvialis Flotow accumulate the ketocarotenoid astaxanthin under stress conditions, such as high irradiance, nutrient deficiency, high salinity, and high temperature. Though some photoprotective mechanisms have been suggested, the function of astaxanthin in red cysts is still questioned. We studied the role of astaxanthin in photoprotection by inducing its formation in logarithmically growing cultures by high irradiance, thus avoiding unrelated processes that can occur in H. pluvialis when carotenogenesis is induced by other stresses. On exposure to high irradiance, the green Haematococcus culture turned red as lipid globules loaded with astaxanthin esters were formed and concentrated at the periphery of the cell. During this phase of induction, the photosynthesis rates remained high, but the amount of the D1 protein of PSII was significantly reduced. The decline in D1 protein content stopped after 1 day; the level then increased, returning to normal after 5 days. The response of the D1 protein was indicative of a transitional phase in the acclimation of Haematococcus to high light. The formation and deposition of astaxanthin seemed to prevent further reduction in D1 protein level, thus enabling the cell to maintain PSII function and structural integrity. This result seems to be a clear indication of the light screening by astaxanthin, which absorbs light in the blue region, thus protecting the photosynthetic apparatus. When the cells recovered from the high light stress, the astaxanthin globules concentrated around the nucleus, indicating that the pigment also serves as a physicochemical barrier, protecting the replicating DNA from oxidation as the cells divide. 相似文献
16.
Accumulation of canthaxanthin in Chlorella emersonii 总被引:1,自引:0,他引:1
A strain of Chlorella emersonii grown under high light intensity and low nitrogen degrades its chlorophyll and synthesizes canthaxanthin as the major carotenoid. Nitrogen starvation or high light alone does not induce canthaxanthin production. Norflurazon, a carotene inhibitor at the level of phytoene desaturase, inhibits production of canthaxanthin in C. emersonii with no accumulation of phytoene. Chlorella vulgaris and C. sp. 993 exposed to similar conditions do not respond in the same way as C. emersonii . 相似文献
17.
There is increasing evidence that the sucrose normally added to the culture medium affects negatively the photosynthetic capacity of plantlets. At the same time, however, sucrose cannot be eliminated from the medium, as it is required for normal in vitro growth. We argue that this is true only under the conventional light conditions of growth-rooms. In the present paper irradiance of growth-rooms was increased 10 times and although the sucrose-inhibitory effect was found at high sucrose concentrations, it was possible to grow coconut (Cocos nucifera L.) plantlets without sucrose. Those plantlets showed both high photosynthetic capacity and comparable in vitro growth to those grown with sucrose in the medium under conventional growth-room irradiance. Nevertheless, the best growth was achieved under mixotrophic conditions where at high irradiance and moderate sucrose concentrations plantlets accumulated 27 % more biomass than plantlets grown without sucrose under high irradiance and 43 and 73 % more biomass than their counterparts at low irradiance with or without sucrose, respectively. 相似文献
18.
Under certain culture conditions, cells of the chlorophyte Haematococcus pluvialis accumulate significant amounts of astaxanthin. This study describes biomass and carotenoid production during a sunlight cycle in a continuous culture of growing cells of H. pluvialis and shows that these two parameters are under the control of irradiance. The hourly carotenoid production increases with light intensity and, in our culture conditions, carotenoid accumulation occurs in a few hours and without any morphological change in the algae. These carotenoids seem to be efficient in protecting algal cells against photoinhibition damage if their content is greater than 1% dry biomass. Below this concentration, that is to say in the early hours of high light intensity, dry biomass decreases due to cell lysis. The results demonstrate that secondary carotenoid accumulation in H. pluvialis may occur in the active growth phase and is stimulated from the first hours of sunlight illumination. 相似文献
19.
We investigated the effect of carbon/nitrogen (C/N) ratio on astaxanthin synthesis in Haematococcus pluvialis during photoautotrophic induction by continuous input of both CO2–air mixture and intense light. When H. pluvialis was induced by constant irradiance induction at 200 μmol photon m−2 s−1, there was a positive correlation with astaxanthin content and C/N ratio, which was similar to the case for heterotrophic
induction. Lower C/N ratios did not retard Haematococcus encystment, but did increase culture biomass, resulting in a decrease in astaxanthin production because of light limitation.
However, induction using variable irradiance showed that reduction of astaxanthin production at low C/N ratios was successfully
overcome by simply increasing the light intensity from 200 to 300 μmol photon m−2 s−1 to overcome the light limitation. This resulted in a greatly enhanced astaxanthin synthesis in proportion to cell density
in cultures with low C/N ratios. Our results indicate that light intensity is more critical than C/N ratio in astaxanthin
production by H. pluvialis during photoautotrophic induction. 相似文献
20.
虾青素具有多种生物学活性,雨生红球藻为天然虾青素的最佳来源,缺氮胁迫会导致雨生红球藻积累虾青素。为了解缺氮条件下雨生红球藻虾青素积累的分子机制,该研究通过对雨生红球藻进行缺氮胁迫,结合MSAP法,研究了雨生红球藻在缺氮胁迫下虾青素积累过程中基因组甲基化水平的变化,结果表明:缺氮胁迫0~72 h期间,雨生红球藻生长速度减慢,而虾青素积累主要发生在缺氮处理12~24 h期间,随后积累速度减慢。同时,对缺氮胁迫0、24、72 h的雨生红球藻基因组DNA进行甲基化敏感扩增多态性分析,共得到了291个甲基化多态性位点,其中发生甲基化变化的位点在0~24 h和24~72 h分别占总位点的29.90%和53.95%。在缺氮胁迫24 h处DNA半甲基化率最大(为12.71%),全甲基化率最低(为26.80%);缺氮胁迫72 h处DNA全甲基化率最高(为28.52%),半甲基化率最低(为1.72%)。这表明DNA甲基化调节方式的改变是虾青素积累过程中的一种重要调控模式。 相似文献