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1.
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
2.
Domínguez-Bocanegra AR Ponce-Noyola T Torres-Muñoz JA 《Applied microbiology and biotechnology》2007,75(4):783-791
Phaffia rhodozyma (now Xanthophyllomyces dendrorhous) and Haematococcus pluvialis are known as the major prominent microorganisms able to synthesize astaxanthin natural pigment. Important research efforts
have been made to determine optimal conditions for astaxanthin synthesis. When the focus is on astaxanthin production, the
maximal reported value of 9.2 mg/g cell is obtained within H. pluvialis grown on BAR medium, under continuous illumination (345 μmol photon m−2 s−1) and without aeration. Whereas fermentation by mutated R1 yeast grown on coconut milk produced 1,850 μg/g yeast. However,
when looking at astaxanthin productivity, the picture is slightly different. The figures obtained with P. rhodozyma are rather similar to those of H. pluvialis. Maximal reported values are 170 μg/g yeast per day with a wild yeast strain and 370 μg/g yeast per day with mutated R1 yeast.
In the case of H. pluvialis, maximal values ranged from 290 to 428 μg/g cell per day depending on the media (BG-11 or BAR), light intensity (177 μmol
photon m−2 s−1), aeration, etc. The main aim of this work was to examine how astaxanthin synthesis, by P. rhodozyma and H. pluvialis, could be compared. The study is based on previous works by the authors where pigment productions have been reported. 相似文献
3.
Y. Kitaya L. Xiao A. Masuda T. Ozawa M. Tsuda K. Omasa 《Journal of applied phycology》2008,20(5):737-742
Symbiotic dinoflagellates of the species Amphidinium are expected to be pharmaceutically useful microalgae because they produce antitumor macrolides. A microalgae production
system with a large number of cells at a high density has been developed for the efficient production of macrolide compounds.
In the present study, the effects of culture conditions on the cellular growth rate of dinoflagellates were investigated to
determine the optimum culture conditions for obtaining high yields of microalgae. Amphidinium species was cultured under conditions with six temperature levels (21–35°C), six levels of photosynthetic photon flux density
(15–70 μmol photons m−2 s−1), three levels of CO2 concentration (0.02–0.1%), and three levels of O2 concentration (0.2–21%). The number of cells cultured in a certain volume of solution was monitored microscopically and the
cellular growth rate was expressed as the specific growth rate. The maximum specific growth rate was 0.022 h−1 at a temperature of 26°C and O2 concentration of 5%, and the specific growth rate was saturated at a CO2 concentration of 0.05%, a photosynthetic photon flux density of 35 μmol photons m−2 s−1 and a photoperiod of 12 h day−1 upon increasing each environmental parameter. The results demonstrate that Amphidinium species can multiply efficiently under conditions of relatively low light intensity and low O2 concentration. 相似文献
4.
M. R. de la Peña 《Journal of applied phycology》2007,19(6):647-655
Two series of experiments were conducted to determine suitable growth factors for the mass propagation of the local algal
isolate Amphora sp. A higher growth rate of 0.2 doubling (μ) day−1 was attained at a lower photosynthetic photon flux density (PPFD; 11.4 μmol photon m−2s−1) compared to cultures exposed to higher levels of PPFD (16.1 μmol photon m−2s−1, −0.1 μ day −1; 31.3 μmol photon m−2s−1, 0.0 μ day−1). Cultures located inside the laboratory had a significantly higher cell density (133 × 104 cells cm−2) and growth rate (0.3 μ day−1) compared to those located outdoors (100 × 104 cells cm−2, 0.2 μ day−1). A comparison of nutrient medium across two locations showed that lipid content was significantly higher in cultures enriched
with F/2MTM (macronutrients + trace metals) and F/2MV (macronutrients + vitamins). Saturated fatty acids were also present
in high concentrations in cultures enriched with F/2M (macronutrients only). Significantly higher amounts of saturated fatty
acids were observed in cultures located outdoors (33.1%) compared to those located indoors (26.6%). The protein, carbohydrates
and n-6 fatty acid content of Amphora sp. were influenced by the location and enrichment of the cultures. This study has identified growth conditions for mass
culture of Amphora sp. and determined biochemical composition under those culture conditions.
Presented at the 6th Meeting of the Asian Pacific Society of Applied Phycology, Manila, Philippines. 相似文献
5.
Mohammad K. Khalesi H. H. Beeftink R. H. Wijffels 《Marine biotechnology (New York, N.Y.)》2009,11(4):488-494
The branching zooxanthellate soft coral Sinularia flexibillis releases antimicrobial and toxic compounds with potential pharmaceutical importance. As photosynthesis by the symbiotic algae
is vital to the host, the light-dependency of the coral, including its specific growth rate (μ day−1) and the physiological response to a range of light intensities (10–1,000 μmol quanta m−2 s−1) was studied for 12 weeks. Although a range of irradiances from 100 to 400 μmol quanta m−2 s−1 was favorable for S. flexibilis, based on chlorophyll content, a light intensity around 100 μmol quanta m−2 s−1 was found to be optimal. The contents of both zooxanthellae and chlorophyll a were highest at 100 μmol quanta m−2 s−1. The specific budding rate showed almost the same pattern as the specific growth rate. The concentration of the terpene flexibilide,
produced by this species, increased at high light intensities (200–600 μmol quanta m−2 s−1). 相似文献
6.
Gracilaria is a potentially valuable source of marine biopolymers such as proteins and polysaccharides. In order to select suitable culture conditions, growth and tolerance of Gracilaria chorda Holmes from Shikoku Island in southwest Japan were investigated under variations of temperature (5–30 ∘C), photon irradiance (20–120 μmol photons m−2 s−1), and photoperiod (12:12 h, 14:10 h light:dark regime) in a unialgal culture. Gracilaria chorda showed wide tolerances for all factors investigated, which is characteristic of eurythermal species. Maximum growth was observed at 18–24 ∘C. The optimum photon irradiance for the algal growth was 60–120 μmol photons m−2s−1. Instead of using ordinary sea salt (NaCl) to prepare artificial seawater, ultra pure salt was adopted. Gracilaria chorda grew faster in artificial seawater made with ultra-pure salt than that made with ordinary sea salt, probably because the former medium was clear, while the latter was milky. Effects of some metal ions on the growth were tested with artificial seawater. Iron ions affected algal growth, but cobalt ions did not. This study enables us to determine suitable culture conditions for G. chorda. A scaled-up 30 l culture of G. chorda under such conditions was successful. 相似文献
7.
Andrea Kodym Stefan Hollenthoner Francisco Javier Zapata-Arias 《In vitro cellular & developmental biology. Plant》2001,37(2):237-242
Summary Daylight instead of artificial light was exploited for the in vitro culture of banana. Tubular skylights rediverted natural light into an interior enelosed room whereby each skylight, available
for ca. US$600, could sufficiently illuminate an area of 3–5 m2. The maintenance-free system allowed only a minimum of heat transfer and no cooling was necessary. The culture room required
no electricity supply and under our conditions savings on costs for electricity of US$6 m−2 wk−1 were achieved, as compared to a standard growth room equipped with artificial lighting and controlled photoperiod and temperature
regimes. Under natural light conditions, micropropagated plantlets were well developed at mean photosynthetic photon flux
densities (PPFD) of 5–13 μmol m−2 s−1 and photoperiods of 9–14 h. Micropropagation rates were either the same or significantly higher than under artificial lighting.
Single shoots on rooting medium showed some symptoms of etiolation, yet acclimatization rates averaged 95%. A step-like culture
rack. rather than a vertical one, permitted uniform plant growth on all levels. This paper describes an established micropropagation
system of low cost and simplicity. 相似文献
8.
Kinetic models for astaxanthin production by high cell density mixotrophic culture of the microalga Haematococcus pluvialis 总被引:3,自引:0,他引:3
High cell density cultivation of Haematococcus pluvialis for astaxanthin production was carried out in batch and fed-batch modes in 3.7-L bioreactors with stepwise increased light
intensity control mode. A high cell density of 2.65 g L−1 (batch culture) or 2.74 g L−1 (fed-batch culture) was obtained, and total astaxanthin production in the fed-batch culture (64.36 mg L−1) was about 20.5% higher than in the batch culture (53.43 mg L−1). An unstructured kinetic model to describe the microalga culture system including cell growth, astaxanthin formation, as
well as sodium acetate consumption was proposed. Good agreement was found between the model predictions and experimental data.
The models demonstrated that the optimal light intensity for mixotrophic growth of H. pluvialis in batch or fed-batch cultures in a 3.7-L bioreactor was 90–360 μmol m−2 s−1, and that the stepwise increased light intensity mode could be replaced by a constant light intensity mode.
Received 24 December 1998/ Accepted in revised form 23 April 1999 相似文献
9.
Light irradiation had remarkable effects on callus growth of Oldenlandia affinis with an optimum intensity of 35 μmol m−2 s−1. Biosynthesis of kalata B1, the main cyclic peptide in O. affinis, was induced and triggered with rising irradiation intensities. The highest concentration of kalata B1, 0.49 mg g−1 DW characterised by the maximum productivity of 3.88 μg per litre and day was analysed at 120 μmol m−2 s−1, although callus growth was repressed. The light saturation point was established to be 35 μmol m−2 s−1, where kalata B1 productivity was in a similar order (3.41 μg per day) due to the higher growth index. O. affinis suspension cultures were shown to accumulate comparable specific kalata B1 concentrations in a delayed growth associated
production pattern. These were dependent on irradiation intensity (0.16 mg g−1 at 2 μmol m−2 s−1; 0.28 mg g−1 at 35 μmol m−2 s−1). The batch cultivation process resulted in a maximum productivity of 27.30 μg per litre and day with culture doubling times
of 1.16 d−1. Submers operation represented a 8-fold product enhancement compared to callus cultivation. 相似文献
10.
Han Gil Choi Ki Hoon Lee Hyun Il Yoo Pil Jun Kang Young Sik Kim Ki Wan Nam 《Journal of applied phycology》2008,20(5):729-735
The effects of temperature, irradiance, and daylength on Sargassum horneri growth were examined at the germling and adult stages to discern their physiological differences. Temperature–irradiance
(10, 15, 20, 25, 30°C × 20, 40, 80 μmol photons m−2s−1) and daylength (8, 12, 16, 24 h) experiments were carried out. The germlings and blades of S. horneri grew over a wide range of temperatures (10–25°C), irradiances (20–80 μmol photons m−2s−1), and daylengths (8–24 h). At the optimal growth conditions, the relative growth rates (RGR) of the germlings were 21% day−1 (25°C, 20 μmol photons m−2s−1) and 13% day−1 (8 h daylength). In contrast, the RGRs of the blade weights were 4% day−1 (15°C, 20 μmol photons m−2s−1) and 5% day−1 (12 h daylength). Negative growth rates were found at 20 μmol photons m−2s−1 of 20°C and 25°C treatments after 12 days. This phenomenon coincides with the necrosis of S. horneri blades in field populations. In conclusion, we found physiological differences between S. horneri germlings and adults with respect to daylength and temperature optima. The growth of S. horneri germlings could be enhanced at 25°C, 20 μmol photons m−2s−1, and 8 h daylength for construction of Sargassum beds and restoration of barren areas. 相似文献
11.
Growth and extracellular polysaccharide production byPorphyridium cruentum were measured as a function of several culture parameters. Photon flux density of 75 μmol m−2 s−1 and CO2 concentration of 2.5% were found to be optimum for both growth and extracellular polysaccharide production. Interactive studies
on these two parameters further confirmed that at these levels of photon flux density and CO2, when applied together, both growth (5.9·107 cells per mL) and extracellular polysaccharide production (1.9 g/L) were at the maximum. Maximum growth and extracellular
polysaccharide production were observed at inoculum density of 106 cells per mL and aeration rate of 500 mL air per min per liter. 相似文献
12.
J. Masojídek M. Sergejevová K. Rottnerová V. Jirka J. Korečko J. Kopecký I. Zaťková G. Torzillo D. Štys 《Journal of applied phycology》2009,21(1):55-63
A novel two-stage experimental photobioreactor (PBR) with a total volume of 450 L and based uniquely on solar concentrators—linear
Fresnel lenses—has been constructed and tested. Daily courses of irradiance, and also its distribution inside cultivation
tubes, were studied in two unit types. The supra-high irradiance units in the ‘roof’ achieved a maximum summer value above
6 mmol photon m−2 s−1, while irradiance in the vertical-facade units was lower than ‘ambient’. In model cultivations, cultures of the cyanobacterium
Arthrospira platensis were cultivated at much higher solar irradiances than those usually recorded outdoors in summer, indicating that this organism
is resilient to high-irradiance (photoinhibition). Starting from a biomass density of 0.5 g L−1 at optimum temperature, the cultures grew exponentially. A two-stage cultivation process of the green microalga Haematococcus pluvialis was investigated with respect to correlations between photochemical activities and astaxanthin production. The culture was
first grown in low-irradiance units, and then exposed to supra-high irradiance when the rate of astaxanthin production was
30–50% higher than in the culture exposed to ‘ambient’ irradiance. Within 4 days, the astaxanthin content reached 3% of dry
weight, whereas under ambient irradiance the astaxanthin content was 25% lower. 相似文献
13.
This work describes the long-term acclimation of the halotolerant microalga Dunaliella viridis to different photon irradiance, ranging from darkness to 1500 μmol m−2 s−1. In order to assess the effects of long-term photoinhibition, changes in oxygen production rate, pigment composition, xanthophyll
cycle and in vivo chlorophyll fluorescence using the saturating pulse method were measured. Growth rate was maximal at intermediate irradiance
(250 and 700 μmol m−2 s−1). The increase in growth irradiance from 700 to 1500 μmol m−2 s−1 did not lead to further significant changes in pigment composition or EPS, indicating saturation in the pigment response
to high light. Changes in Photosystem II optimum quantum yield (Fv/Fm) evidenced photoinhibition at 700 and especially at 1500 μmol m−2 s−1. The relation between photosynthetic electron flow rate and photosyntetic O2 evolution was linear for cultures in darkness shifting to curvilinear as growth irradiance increased, suggesting the interference
of the energy dissipation processes in oxygen evolution. Carbon assimilation efficiencies were studied in relation to changes
in growth rate, internal carbon and nitrogen composition, and organic carbon released to the external medium. All illuminated
cultures showed a high capability to maintain a C:N ratio between 6 and 7. The percentage of organic carbon released to the
external medium increased to its maximum under high irradiance (1500 μmol m−2 s−1). These results suggest that the release of organic carbon could act as a secondary dissipation process when the xanthophyll
cycle is saturated.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
14.
Ganka Chaneva Sevdalina Furnadzhieva Kaledona Minkova Jaromir Lukavsky 《Journal of applied phycology》2007,19(5):537-544
The effect of light intensity (50–300 μmol photons m−2 s−1) and temperature (15–50°C) on chlorophyll a, carotenoid and phycobiliprotein content in Arthronema africanum biomass was studied. Maximum growth rate was measured at 300 μmol photons m−2 s−1 and 36°C after 96 h of cultivation. The chlorophyll a content increased along with the increase in light intensity and temperature and reached 2.4% of dry weight at 150 μmol photons
m−2 s−1 and 36°C, but it decreased at higher temperatures. The level of carotenoids did not change significantly under temperature
changes at illumination of 50 and 100 μmol photons m−2 s−1. Carotenoids were about 1% of the dry weight at higher light intensities: 150 and 300 μmol photons m−2 s−1. Arthronema africanum contained C-phycocyanin and allophycocyanin but no phycoerythrin. The total phycobiliprotein content was extremely high,
more than 30% of the dry algal biomass, thus the cyanobacterium could be deemed an alternative producer of C-phycocyanin.
A highest total of phycobiliproteins was reached at light intensity of 150 μmol photons m−2 s−1 and temperature of 36°C, C-phycocyanin and allophycocyanin amounting, respectively, to 23% and 12% of the dry algal biomass.
Extremely low (<15°C) and high temperatures (>47°C) decreased phycobiliprotein content regardless of light intensity. 相似文献
15.
Terence J. Evens Randall P. Niedz Gary J. Kirkpatrick 《Journal of applied phycology》2008,20(4):411-422
The microalga Haematococcus pluvialis Flotow has been the subject of a number of studies concerned with maximizing astaxanthin production for use in animal feeds
and for human consumption. Several of these studies have specifically attempted to ascertain the optimal temperature and irradiance
combination for growth of H. pluvialis, but there has been a great deal of disagreement between laboratories. “Ideal” levels of temperature and irradiance have
been reported to range from 14 to 28°C and 30 to 200 μmol photons m−2 s−1. The objective of the present study was to simultaneously explore temperature and irradiance effects for a single strain
of H. pluvialis (UTEX 2505) across an experimental region that encompassed the reported “optimal” combinations of these factors for multiple
strains. To this end, a two-dimensional experimental design based on response surface methodology (RSM) was created. Maximum
growth rates for UTEX 2505 were achieved at 27°C and 260 μmol photons m−2 s−1, while maximum quantum yield for stable charge separation at PSII (Fv/Fm) was achieved at 27°C and 80 μmol photons m−2 s−1. Maximum pigment concentrations correlated closely with maximum Fv/Fm. Numeric optimization of growth rate and Fv/Fm produced an optimal combination of 27°C and 250 μmol photons m−2 s−1. Polynomial models of the various response surfaces were validated with multiple points and were found to be very useful
for predicting several H. pluvialis UTEX 2505 responses across the entire two-dimensional experimental design space. 相似文献
16.
Tetraspores of Sarcothalia crispata from San Juan Bay, Strait of Magellan, Chile, were cultivated under different combinations of photon flux densities and agricultural
fertilizers in the laboratory. In the experiment, the S. crispata specimens were cultured in combinations of different photon flux densities (50, 100, 150 μmol photons m-2 s-1) and enriched seawater solutions (sodium nitrate + monocalcium phosphate, urea + monocalcium phosphate, ammonium nitrate
+ monocalcium phosphate), always adjusting the N and P concentrations to 10 and 3 mg L-1, and in sea water as control. After 45 days, the tetrasporeling plants were found to be larger at photon flux densities of
50 and 100 μmol photons m-2 s-1 in the nutrient enrichment experiments; growth was greatest in the sea water enriched with ammonium nitrate and urea. An
analysis of the combined effect of the photon flux density and nutrients revealed that the best combination for sporeling
growth was the ammonium nitrate and urea solution at 50–100 μmol photons m-2 s-1. 相似文献
17.
The activity of 3-deoxy-D-arabino-heptulosonate 7-phosphate (DAHP) synthase (DS-Mn, DS-Co), phenylalanine ammonia-lyase (PAL),
and chalcone synthase (CHS) was monitored at various light intensities (dark, 8.88 μmol m−2 s−1, 88.8 μmol m−2 s−1) using a strawberry cell suspension culture. DS-Mn, PAL, and CHS were found to increase significantly (p>0.05) under light intensitie of 88.8 μmol m−2 s−1 compared to those of 8.88 μmol m−2 s−1 and dark. The activity of DS-Mn, PAL, and CHS were maximum at 88.8 μmol m−2 s−1. Anthocyanin content reached a maximum after 48–60 h of culturing at 88.8 μmol m−2 s−1. DS-Co showed greater activity than DS-Mn during cell culturing, but showed no correlation with anthocyanin production and
light intensity. The CHS gene expression was continuous at a light intensity of 88.8 μmol m−2 s−1.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
18.
Vegetative reproduction of Chondracanthus chamissoi by means of fragmentation and re-attachment of thalli is considered an effective strategy for maintaining natural populations
of this species. Here, we evaluate the effects of (1) time of drifting thallus, (2) type of substratum, and (3) photon flux
density, on the re-attachment capacity of thallus fragments of C. chamissoi. The results show that re-attachment decreases with the time after detachment, and was higher at the lower photon flux densities
tested (10 and 40 μmol photons m−2s−1), and on calcareous substratum. Secondary attachment discs are formed along the entire surface of the fragment. 相似文献
19.
Photosynthetic photon flux density (PPFD) at 15 cm above the ground was measured at 20 microsites in gaps and grass patches
within aMiscanthus sinensis Anderss community at 10 s intervals during 5 days every month from May to September 1989.
Microsite light availability, which was characterized by daily total PPFD, sunfleck PPFD (PPFD above a threshold value of
50 or 400 μmol m−2 s−1) and the diffuse site factor, showed evident seasonal changes, with a marked reduction between June and July due to the rapid
growth of the grass canopy. The monthly median value of daily total PPFD among the microsites decreased from 10.3 mol m−2 day−1 in May to 0.77 mol m−2 day−1 in September, with a reduction in the diffuse site factor from 31 to 4%. During the summer, the median value of the total
time of sunflecks exceeding 50 μmol m−2 s−1 contributed 7–18% of measurement time, but the contribution of these sunflecks to daily total PPFD ranged from 29 to 59%.
There was considerable microsite variation in light availability throughout the measurement period. Rank correlation analysis
revealed that some microsites, such as those in gaps, consistently received more total PPFD, more sunfleck PPFD and had a
higher diffuse site factor than those in grass patches. The diffuse site factor had a linearly positive relationship with
daily total PPFD and total sunfleck PPFD for the 20 microsites during the measurement period, confirming that the diffuse
site factor is a useful index for microsite light availability withinM. sinensis canopies. 相似文献
20.
Carbon dioxide compensation concentration,Г, net photosynthetic rate,Pn, and photorespiration rate,Rl, were measured in young, adult and old primary leaves ofPhaseolus vulgaris L. over a range of photon flux densities using a closed system with IRGA. Irrespective of leaf age,Г decreased rapidly with rising photon flux density up toca. 260 (μmol m−2 s−1. From this valueГ did not change with photon flux density under constant temperature, reaching on the average 178, 118 and 239 mg m−3 in young, adult and old leaves, respectively. Changes with age in curves relatingPn andRl to photon flux density were found. 相似文献