共查询到20条相似文献,搜索用时 31 毫秒
1.
Bo Xie Dan Stessman Jason H. Hart Haili Dong Yingjun Wang David A. Wright Basil J. Nikolau Martin H. Spalding Larry J. Halverson 《Plant biotechnology journal》2014,12(7):872-882
The genetically tractable microalga Chlamydomonas reinhardtii has many advantages as a model for renewable bioproducts and/or biofuels production. However, one limitation of C. reinhardtii is its relatively low‐lipid content compared with some other algal species. To overcome this limitation, we combined ethane methyl sulfonate mutagenesis with fluorescence‐activated cell sorting (FACS) of cells stained with the lipophilic stain Nile Red to isolate lipid hyperaccumulating mutants of C. reinhardtii. By manipulating the FACS gates, we sorted mutagenized cells with extremely high Nile Red fluorescence signals that were rarely detected in nonmutagenized populations. This strategy successfully isolated several putative lipid hyperaccumulating mutants exhibiting 23% to 58% (dry weight basis) higher fatty acid contents than their progenitor strains. Significantly, for most mutants, nitrogen starvation was not required to attain high‐lipid content nor was there a requirement for a deficiency in starch accumulation. Microscopy of Nile Red stained cells revealed that some mutants exhibit an increase in the number of lipid bodies, which correlated with TLC analysis of triacyglycerol content. Increased lipid content could also arise through increased biomass production. Collectively, our findings highlight the ability to enhance intracellular lipid accumulation in algae using random mutagenesis in conjunction with a robust FACS and lipid yield verification regime. Our lipid hyperaccumulating mutants could serve as a genetic resource for stacking additional desirable traits to further increase lipid production and for identifying genes contributing to lipid hyperaccumulation, without lengthy lipid‐induction periods. 相似文献
2.
A fluorescence‐activated cell sorting‐based strategy for rapid isolation of high‐lipid Chlamydomonas mutants 下载免费PDF全文
Mia Terashima Elizabeth S. Freeman Robert E. Jinkerson Martin C. Jonikas 《The Plant journal : for cell and molecular biology》2015,81(1):147-159
There is significant interest in farming algae for the direct production of biofuels and valuable lipids. Chlamydomonas reinhardtii is the leading model system for studying lipid metabolism in green algae, but current methods for isolating mutants of this organism with a perturbed lipid content are slow and tedious. Here, we present the Chlamydomonas high‐lipid sorting (CHiLiS) strategy, which enables enrichment of high‐lipid mutants by fluorescence‐activated cell sorting (FACS) of pooled mutants stained with the lipid‐sensitive dye Nile Red. This method only takes 5 weeks from mutagenesis to mutant isolation. We developed a staining protocol that allows quantification of lipid content while preserving cell viability. We improved separation of high‐lipid mutants from the wild type by using each cell's chlorophyll fluorescence as an internal control. We initially demonstrated 20‐fold enrichment of the known high‐lipid mutant sta1 from a mixture of sta1 and wild‐type cells. We then applied CHiLiS to sort thousands of high‐lipid cells from a pool of about 60 000 mutants. Flow cytometry analysis of 24 individual mutants isolated by this approach revealed that about 50% showed a reproducible high‐lipid phenotype. We further characterized nine of the mutants with the highest lipid content by flame ionization detection and mass spectrometry lipidomics. All mutants analyzed had a higher triacylglycerol content and perturbed whole‐cell fatty acid composition. One arbitrarily chosen mutant was evaluated by microscopy, revealing larger lipid droplets than the wild type. The unprecedented throughput of CHiLiS opens the door to a systems‐level understanding of green algal lipid biology by enabling genome‐saturating isolation of mutants in key genes. 相似文献
3.
To advance the utilization of microalgae as a viable feedstock for biodiesel production, the intracellular lipid content of three strains of the marine microalgae Nannochloropsis sp. was enhanced using flow cytometry (FC) coupled with cell sorting. Total lipid content was doubled to 55% (biomass dry weight) in the sorted, daughter cells of Nannochloropsis (strain 47) after consecutive three rounds of cell sorting, and this trait was maintained for approximately 100 subsequent cell generations. In addition, daughter cells had a fatty acid profile similar to that of the parent, wild‐type strain. The study demonstrates that FC coupled with cell sorting is a powerful tool for the enhancement of intracellular lipid content in microalgae exploited for biodiesel feedstock. 相似文献
4.
Effects of nitrogen sources on cell growth and lipid accumulation of green alga <Emphasis Type="Italic">Neochloris oleoabundans</Emphasis> 总被引:8,自引:0,他引:8
Microalgal lipids are the oils of future for sustainable biodiesel production. However, relatively high production costs due
to low lipid productivity have been one of the major obstacles impeding their commercial production. We studied the effects
of nitrogen sources and their concentrations on cell growth and lipid accumulation of Neochloris oleoabundans, one of the most promising oil-rich microalgal species. While the highest lipid cell content of 0.40 g/g was obtained at
the lowest sodium nitrate concentration (3 mM), a remarkable lipid productivity of 0.133 g l−1 day−1 was achieved at 5 mM with a lipid cell content of 0.34 g/g and a biomass productivity of 0.40 g l−1 day−1. The highest biomass productivity was obtained at 10 mM sodium nitrate, with a biomass concentration of 3.2 g/l and a biomass
productivity of 0.63 g l−1 day−1. It was observed that cell growth continued after the exhaustion of external nitrogen pool, hypothetically supported by the
consumption of intracellular nitrogen pools such as chlorophyll molecules. The relationship among nitrate depletion, cell
growth, lipid cell content, and cell chlorophyll content are discussed. 相似文献
5.
G. S. Kalacheva N. N. Sushchik M. I. Gladyshev O. N. Makhutova 《Russian Journal of Plant Physiology》2009,56(6):795-807
Identification of lipid fatty acids (FA) and studying of their seasonal dynamics in water moss Fontinalis antipyretica from the Yenisei River were carried out by means of gas chromatography-mass spectrometry. FA composition of water moss was
notable for a relatively low level of saturated acids and predominance of polyunsaturated acids (PUFA) with double bonds (accounting
for more than 30% of total FA) and polyunsaturated acids with double and triple bonds (acetylenic acids, accounting for more
than 40% of total FA). Among PUFA, α- and γ-linolenic (18:3ω3 and 18:3ω6), arachidonic (20:4ω6), and eicosapentaenoic (20:5ω3)
acids prevailed. Relative content of PUFA from ω3-family was the greatest in spring, and the level of PUFA from ω6-group was
essentially the same throughout all the seasons. In the biomass of water moss, we identified seven acetylenic acids; among
them octadeca-9,12-dien-6-ynoic (6a,9,12-18:3), octadeca-9,12,15-trien-6-ynoic (6a,9,12,15-18:4), and eicosa-11,14-dien-8-ynoic
(8a,11,14-20:3) acids were predominant. For the first time, in the lipids of water moss we identified an acetylenic eicosa-11,14,17-trien-8-ynoic
acid (8a,11,14,15-20:4). Relative content of acetylenic acids in the total FA was great throughout the entire period of investigation
with the peak accumulation in summer. Owing to a steadily high level in the biomass of water moss and the lack of other producers
of these acids in the ecosystem, acetylenic FA are highly specific biochemical markers useful for the investigation of trophic
interactions between higher aquatic plants and zoobenthos. 相似文献
6.
David Sternberg Stephen R. Balcombe Jonathan C. Marshall Jaye S. Lobegeiger Angela H. Arthington 《Environmental Biology of Fishes》2012,93(1):95-104
The ecology of dryland rivers is driven by their highly variable hydrology, particularly flooding regimes, whereby intermittent
floods typically generate ‘booms’ of primary and secondary productivity, including massive fish production. We tested these
concepts in the Moonie River, Australia, using the percichthyid, Macquaria ambigua, a dryland river species known to display pronounced ‘boom and bust’ abundance patterns in response to floodplain inundation
followed by extended periods of low to no channel flow. We expected that body condition (as measured by whole body lipid content)
and biomass of M. ambigua would be related to prey biomass, and that these factors would all ‘spike’ following widespread flooding. Instead we found
more subtle responses. There were ‘booms’ in biomass of Macrobrachium and zooplankton, two important food items, whereas M. ambigua maintained relatively low but sustained lipid and biomass levels following flooding. It appears that instead of a ‘boom’
in fish biomass, abundant invertebrate food resources and sustained lipid levels contributed to high survivorship of this
species during the ‘bust’ period over cool dry months. 相似文献
7.
Because of its high growth rate at low temperatures in early spring, there is renewed interest in Brassica rapa as a winter crop for biomass production in Europe. The available cultivars are not developed for this purpose however. An
approach for breeding bioenergy cultivars of B. rapa could be to establish populations from two or more different cultivars with high combining ability. The objective of this
study was to evaluate the heterosis for biomass yield in the European winter B. rapa genepool. The genetic variation and heterosis of the biomass parameters: dry matter content, fresh and dry biomass yields
were investigated in three cultivars representing different eras of breeding by comparing full-sibs-within and full-sibs-between
the cultivars. Field trials were performed at two locations in Germany in 2005–2006. Mean mid-parent heterosis was low with
2.5% in fresh and 3.0% in dry biomass yield in full-sibs-between cultivars. Mean values of individual crosses revealed a higher
variation in mid-parent heterosis ranging from 14.6% to −7.5% in fresh biomass yield and from 19.7% to −12.7% in dry biomass
yield. The low heterosis observed in hybrids between European winter cultivars can be explained by the low genetic variation
between these cultivars as shown earlier with molecular markers. In conclusion, a B. rapa breeding program for biomass production in Europe should not only use European genetic resources, but should also utilize
the much wider worldwide variation in this species. 相似文献
8.
Two years of measurements are explored with a view to formulating an ecosystem model for Myall Lake. Stable physical characteristics,
low catchment loads, low light attenuation, flat-bottomed hypsometry, and soft gyttja substrate allow stable charophyte biomass
throughout the year in Myall Lake. Chara fibrosa dominates the total biomass and is abundant over the depth range 0.5–4 m. Nitella hyalina is found over the same depth range but has diminished biomass at depths greater than 2 m due to increased incidence of zero-biomass
samples at depths greater than 1.5 m. Upper bounds for biomass densities were estimated for charophytes. Najas marina has great seasonal variability and meadows can have very high biomass in waters 1.5–2.7 m deep. High biomass of Najas marina is associated with low biomass of Nitella hyalina and may be a factor determining how the biomass of Nitella hyalina is distributed with respect to depth. Patchiness of Najas marina is particularly high. Temperature and light can support two growing seasons for Najas marina but mechanical disturbance is often high in spring and high biomass was only observed in late autumn during the present study.
Less than 5% of the present-day production of submerged macrophytes would have been required to produce organic material of
the gyttja over a 1,000-year period. The spatial distributions of gyttja and the dominant macrophytes are consistent with
wind patterns. Down-lake limits on the distributions of charophytes and Najas marina are related to a gradient in the coefficient of light attenuation that is, in turn, related to proximity to the bulk of the
catchment load. 相似文献
9.
Sirisansaneeyakul S Singhasuwan S Choorit W Phoopat N Garcia JL Chisti Y 《Marine biotechnology (New York, N.Y.)》2011,13(5):928-941
The microalgae Chlorella protothecoides UTEX 25, Chlorella sp. TISTR 8991, and Chlorella sp. TISTR 8990 were compared for use in the production of biomass and lipids under photoautotrophic conditions. Chlorella sp. TISTR 8990 was shown to be potentially suitable for lipid production at 30°C in a culture medium that contained only
inorganic salts. For Chlorella sp. TISTR 8990 in optimal conditions in a stirred tank photobioreactor, the lipid productivity was 2.3 mg L−1 h−1 and after 14 days the biomass contained more than 30% lipids by dry weight. To attain this, the nitrogen was provided as
KNO3 at an initial concentration of 2.05 g L−1 and chelated ferric iron was added at a concentration of 1.2 × 10−5 mol L−1 on the ninth day. Under the same conditions in culture tubes (36 mm outer diameter), the biomass productivity was 2.8-fold
greater than in the photobioreactor (0.125 m in diameter), but the lipid productivity was only 1.2-fold higher. Thus, the
average low-light level in the photobioreactor actually increased the biomass specific lipid production compared to the culture
tubes. A light-limited growth model closely agreed with the experimental profiles of biomass production, nitrogen consumption,
and lipid production in the photobioreactor. 相似文献
10.
Sang Do Yook Jiwon Kim Gyeongtack Gong Ja Kyong Ko Youngsoon Um Sung Ok Han Sun‐Mi Lee 《Global Change Biology Bioenergy》2020,12(9):670-679
Lignocellulosic biomass shows high potential as a renewable feedstock for use in biodiesel production via microbial fermentation. Yarrowia lipolytica, an emerging oleaginous yeast, has been engineered to efficiently convert xylose, the second most abundant sugar in lignocellulosic biomass, into lipids for lignocellulosic biodiesel production. Yet, the lipid yield from xylose or lignocellulosic biomass remains far lower than that from glucose. Here we developed an efficient xylose‐utilizing Y. lipolytica strain, expressing an isomerase‐based pathway, to achieve high‐yield lipid production from lignocellulosic biomass. The newly developed xylose‐utilizing Y. lipolytica, YSXID, produced 12.01 g/L lipids with a maximum yield of 0.16 g/g, the highest ever reported, from lignocellulosic hydrolysates. Consequently, this study shows the potential of isomerase‐based xylose‐utilizing Y. lipolytica for economical and sustainable production of biodiesel and oleochemicals from lignocellulosic biomass. 相似文献
11.
A novel biosuperabsorbent protein hydrogel was prepared from protein-rich alcoholic–alkali soluble parts of zygomycete Rhizomucor pusillus biomass. The fungal protein content was 46.8%, and the lipid content was 13.1%. Extraction of protein from this microorganism
through the method applied prevents protein decomposition, resulting in maximum yield. After alcoholic–alkaline extraction,
the proteins from the biomass were acylated using ethylenediaminetetraacetic dianhydride and subsequently treated with glutaraldehyde
as a crosslinker for further experiments. Thermal consistency was investigated by means of two different methods: thermal
denaturation via differential scanning calorimetry and thermal decomposition study via thermogravimetric analysis. The swelling
behaviour of the crosslinked hydrogel was measured in deionised water, 0.9% NaCl solution and synthetic urine, which were
87.6, 43 and 38.6 g/g water after 24 h, respectively. Moreover, the isoelectric point (pI) of the hydrogel was determined as pH = 8 by studying swelling behaviour at different pHs. In addition, the dependencies
of the swelling behaviour with regard to the chemical modification, the ionic strength, the degree of crosslinking, as well
as water absorbency with or without load were studied. 相似文献
12.
High-throughput screening of microalgae for use as a potential feedstock for biodiesel requires a reliable method for the
rapid detection of intracellular neutral lipid content. In this study, we report a modified and improved Nile Red (NR) fluorescence
staining procedure for use as a rapid and sensitive screening tool to estimate levels of intracellular neutral lipid in the
picopleustonic microalgae, Nannochloropsis sp. Addition of either glycerol or dimethyl sulfoxide (DMSO) into microalgae cultures greatly enhances lipid staining efficiency
and increases the fluorescence intensity of stained cells. The optimized procedure requires glycerol and DMSO at the concentration
of 0.1 and 0.165 g mL−1, respectively, for peak fluorescence in a live culture of Nannochloropsis sp. Incubation for 5 min for glycerol-NR staining and 10 min for DMSO-NR staining at room temperature, in darkness, is used for
the NR concentration of 0.3 and 0.7 μg mL−1 for glycerol and DMSO, respectively. For the selection of lipid-rich cells of Nannochloropsis sp. using flow cytometric cell sorting, the glycerol-NR procedure is recommended as glycerol, unlike DMSO, does not inhibit
subsequent growth of sorted cells. 相似文献
13.
Chanika Saenge Benjamas Cheirsilp Thanwadee Tachapattaweawrakul Suksaroge Thawien Bourtoom 《Biotechnology and Bioprocess Engineering》2011,16(1):23-33
Rhodotorula glutinis TISTR 5159 is oleaginous red yeast that accumulates both lipids and carotenoids. It was cultured in palm oil mill effluent
(POME) with only the addition of ammonium sulfate and Tween 20 as a suitable nitrogen source and surfactant, respectively.
Response surface methodology (RSM) was applied to optimize initial chemical oxygen demand (COD) in POME, C/N ratio, and Tween
20 concentration for concomitant production of lipids and carotenoids. Among three investigated factors, C/N ratio contributed
a significant effect upon lipid and carotenoids production. Analysis of response surface plots revealed that the optimum C/N
ratio for the biomass was 140, while that for lipid content and carotenoids were higher at 180 and 170, respectively. The
high level of the nitrogen source (with a low C/N ratio) enhanced the biomass, making the accumulation of lipids and carotenoids
less preferable. Hence, the two-stage process was attempted as an optimal way for cell growth in the first stage and product
accumulation in the second stage. The lipid yield and carotenoid production obtained in the two-stage process were higher
than those in the one-stage process. In the semi-continuous fermentation, R. glutinis TISTR 5159 accumulated high lipid content and produced a considerably high concentration of carotenoids during long-term
cultivation. Additionally, efficient COD removal by R. glutinis TISTR 5159 was observed. The biodiesel produced from yeast lipids was composed mainly of oleic and palmitic acids, similar
to those from plant oil. 相似文献
14.
To evaluate the effects of allochthonous litter input on the population density of invasive red swamp crayfish (Procambarus clarkii) in Japanese farm ponds, we analyzed gut contents, stable isotope ratios, and the correlation between crayfish biomass and
environmental factors in the ponds. For our correlation analysis, we used Akaike’s information criterion (AIC) corrected for
small sample size (AICC) to select appropriate models within the generalized linear model. Allochthonous litter input was the most influential variable
affecting crayfish biomass, followed by pond area. Gut content analysis demonstrated a positive correlation between the percentage
of litter in the crayfish gut and the amount of litter input into the pond from which animals were collected. Crayfish δ13C became increasingly similar to litter δ13C as litter input into ponds increased. Nitrogen isotope signature analysis suggested that microorganisms attached to litter
may contribute to crayfish diet. The above results obtained by three complementary approaches demonstrated an important influence
of allochthonous litter input on crayfish biomass in farm ponds. We propose that the appropriate management of surrounding
forests may be effective in controlling the abundance of exotic crayfish with minimized impacts on native communities. 相似文献
15.
Biodiesel from microalgae seems to be the only renewable biofuel that has the potential to completely replace the petroleum-derived
transport fuels. Therefore, improving lipid content of microalgal strains could be a cost-effective second generation feedstock
for biodiesel production. Lipid accumulation in Scenedesmus obliquus was studied under various culture conditions. The most significant increase in lipid reached 43% of dry cell weight (dcw),
which was recorded under N-deficiency (against 12.7% under control condition). Under P-deficiency and thiosulphate supplementation
the lipid content also increased up to 30% (dcw). Application of response surface methodology in combination with central
composite rotary design (CCRD) resulted in a lipid yield of 61.3% (against 58.3% obtained experimentally) at 0.04, 0.03, and
1.0 g l−1 of nitrate, phosphate, and sodium thiosulphate, respectively for time culture of 8 days. Scenedesmus cells pre-grown in glucose (1.5%)-supplemented N 11 medium when subjected to the above optimized condition, the lipid accumulation
was boosted up to 2.16 g l−1, the value ~40-fold higher with respect to the control condition. The presence of palmitate and oleate as the major constituents
makes S. obliquus biomass a suitable feedstock for biodiesel production. 相似文献
16.
We tested 10 different Chlorella and Parachlorella strains under lipid induction growth conditions in autotrophic laboratory cultures. Between tested strains, substantial differences
in both biomass and lipid productivity as well as in the final content of lipids were found. The most productive strain (Chlorella vulgaris CCALA 256) was subsequently studied in detail. The availability of nitrates and/or phosphates strongly influenced growth
and accumulation of lipids in cells by affecting cell division. Nutrient limitation substantially enhanced lipid productivity
up to a maximal value of 1.5 g l−1 day−1. We also demonstrated the production of lipids through large-scale cultivation of C. vulgaris in a thin layer photobioreactor, even under suboptimal conditions. After 8 days of cultivation, maximal lipid productivity
was 0.33 g l−1 day−1, biomass density was 5.7 g l−1 dry weight and total lipid content was more than 30% dry weight. C. vulgaris lipids comprise fatty acids with a relatively high degree of saturation compared with canola oil offering a possible alternative
to the use of higher plant oils. 相似文献
17.
Blanco AM Moreno J Del Campo JA Rivas J Guerrero MG 《Applied microbiology and biotechnology》2007,73(6):1259-1266
The growth performance of the chlorophycean microalga Muriellopsis sp. outdoors in open tanks agitated with a paddlewheel and its ability to accumulate carotenoids have been evaluated throughout
the year. The cells grown in the open system had free lutein as the main carotenoid, with violaxanthin, β-carotene, and neoxanthin
also present. Lutein content of the dry biomass ranged from 0.4 to 0.6%, depending on the growth and environmental conditions.
In addition, the biomass of Muriellopsis sp. had a high content in both protein and lipids with about half of the fatty acids being of the polyunsaturated type, with
α-linolenic acid accounting for almost 30% of the total fatty acids. The effect of determinant parameters on the performance
of the cultures in open tanks was evaluated. Operating conditions that allow the maintenance of productive cultures were established
under semicontinuous regime for 9 months throughout the year. Biomass and lutein yields in the open system were not far from
those in closed tubular photobioreactors, and reached productivity values of 20 g dry biomass, containing around 100 mg lutein
m−2 day−1 in summer. The outdoor culture of Muriellopsis sp. in open ponds thus represents a real alternative to established systems for the production of lutein. 相似文献
18.
Björn J. Gosch Marie Magnusson Nicholas A. Paul Rocky de Nys 《Global Change Biology Bioenergy》2012,4(6):919-930
We investigated the potential of seaweeds as feedstock for oil‐based products, and our results support macroalgae (seaweeds) as a biomass source for oil‐based bioproducts including biodiesel. Not only do several seaweeds have high total lipid content above 10% dry weight, but in the brown alga Spatoglossum macrodontum 50% of these lipids are in the form of extractable fatty acids. S. macrodontum had the highest fatty acid content (57.40 mg g?1 dw) and a fatty acid profile rich in saturated fatty acids with a high content of C18:1, which is suitable as a biofuel feedstock. Similarly, the green seaweed Derbesia tenuissima has high levels of fatty acids (39.58 mg g?1 dw), however, with a high proportion of PUFA (n‐3) (31% of total lipid) which are suitable as nutraceuticals or fish oil replacements. Across all species of algae the critical parameter of fatty acid content (measured as fatty acid methyl esters, FAME) was positively correlated (R2 = 0.67) with total lipid content. However, the proportion of fatty acids to total lipid decreased markedly with total lipid content, generally between 30% and 50%, making it an inaccurate measure of the potential to identify seaweeds suitable for oil‐based bioproducts. Finally, we quantified within species variation of fatty acids across locations and sampling periods supporting either environmental effects on quantitative fatty acid profiles, or genotypes with specific quantitative fatty acid profiles, thereby opening the possibility to optimize the fatty acid content and quality for oil production through specific culture conditions and selective breeding. 相似文献
19.
Solovchenko A Khozin-Goldberg I Recht L Boussiba S 《Marine biotechnology (New York, N.Y.)》2011,13(3):527-535
In order to develop a practical approach for fast and non-destructive assay of total fatty acid (TFA) and pigments in the
biomass of the marine microalga Nannochloropsis sp. changes in TFA, chlorophyll, and carotenoid contents were monitored in parallel with the cell suspension absorbance.
The experiments were conducted with the cultures grown under normal (complete nutrient f/2 medium at 75 μmol PAR photons/(m2 s)) or stressful (nitrogen-lacking media at 350 μmol PAR photons/(m2 s)) conditions. The reliable measurement of the cell suspension absorbance using a spectrophotometer without integrating
sphere was achieved by deposition of cells on glass–fiber filters in the chlorophyll content range of 3–13 mg/L. Under stressful
conditions, a 30–50% decline in biomass and chlorophyll, retention of carotenoids and a build-up of TFA (15–45 % of dry weight)
were recorded. Spectral regions sensitive to widely ranging changes in carotenoid-to-chlorophyll ratio and correlated changes
of TFA content were revealed. Employing the tight inter-correlation of stress-induced changes in lipid metabolism and rearrangement
of the pigment apparatus, the spectral indices were constructed for non-destructive assessment of carotenoid-to-chlorophyll
ratio (range 0.3–0.6; root mean square error (RMSE) = 0.03; r
2 = 0.93) as well as TFA content of Nannochloropsis sp. biomass (range 5.0–45%; RMSE = 3.23 %; r
2 = 0.89) in the broad band 400–550 nm normalized to that in chlorophyll absorption band (centered at 678 nm). The findings
are discussed in the context of real-time monitoring of the TFA accumulation by Nannochloropsis cultures under stressful conditions. 相似文献
20.
Freddy Guihéneuf Manuela Fouqueray Virginie Mimouni Lionel Ulmann Boris Jacquette Gérard Tremblin 《Journal of applied phycology》2010,22(5):629-638
Polyunsaturated fatty acids (PUFAs), especially eicosapentaenoic and docosahexaenoic acids (EPA and DHA), are abundantly synthesized
by some phytoplankton species and play a key role in the marine food chain. However, they are generally considered to be sensitive
to oxidation by UV radiation (UV-R). In order to investigate the effect of UV-R on the lipid composition of two marine microalgae,
Pavlova lutheri and Odontella aurita, they were exposed to a combination of UVA-R and UVB-R with a total UV-R daily dose of 110 kJ m−2. Chlorophyll a, photochemical efficiency, and lipid composition were then determined on days 3, 5, and 8 of UV-R exposure. In P. lutheri, exposure to UV-R treatment led to a decrease in the proportions of PUFAs, such as EPA and DHA, especially into structural
lipids (glycolipids and phospholipids). Our findings reveal a reduction of 20% in EPA levels and 16% in DHA levels, after
8 days of UV-R treatment. In O. aurita, exposure to UV-R did not change the fatty acid composition of the total lipids and lipid fractions of the cells. EPA levels
remained high (27–28% of total lipids) during the 8 days of treatment. Consequently, the n-3 fatty acid content of P. lutheri was altered which highlights the sensitivity of this species to UV-R, whereas the results obtained for O. aurita suggest a more UV-R resistance. As a result, in latitude countries with medium UV-R level, outdoor “race-way” culture of
O. aurita could yield a high-EPA algal biomass, whatever the seasonal variations in UV-R. 相似文献