Downstream processing and purification of eicosapentaenoic (20:5n-3) and arachidonic acids (20:4n-6) from the microalga Porphyridium cruentum

Eicosapentaenoic acid (FPA, 20:5n-3) and arachidonic acid (AA, 20:4n-3)were obtained from the microalga Porphyridium cruentum by a three-stepprocess: fatty acid extraction by direct saponification of biomass,polyunsaturated fatty acid (PUFA) concentration by urea inclusion complexingand EPA isolation by high-performance liquid chromatography (HPLC). Twosolvents were tested for direct saponification of lipids in biomass. Themost efficient solvent, ethanol (96% v/v), extracted 75% ofthe fatty acids. PUFAs concentration by urea inclusion employed a urea/fattyacid ratio of 4:1 wt/wt at the crystallization temperatures of 4°C and28°C. Concentration factors were similar at both temperatures, but theEPA and AA recoveries were higher at 28°C (67.7% and 61.8%for the two acids, respectively). EPA and AA were purified from this PUFAconcentrate using analytical scale HPLC and the best results of thisseparation were scaled up to preparative level (4.7 i. d. × 30 cmcompression radial cartridge). A 94.3% pure EPA fraction and a81.4% pure AA fraction were obtained. Suitability of severalmicroalgae (Porphyridium cruentum, Phaeodactylum tricornutum and Isochrysisgalbana) and cod liver oil as sources of highly pure PUFAs, mainly EPA, wascompared.     

Eicosapentaenoic and arachidonic acids purification from the red microalga Porphyridium cruentum

The polyunsaturated fatty acids (PUFA) eicosapentaenoic and arachidonic acids (EPA and AA), which have several pharmaceutical properties, have been purified from the red microalga Porphyridium cruentum. The process consists of only four main steps: (i) simultaneous extraction and saponification of the microalgal biomass; (ii) urea inclusion method (iii) PUFA esterification (iv) argentated silica gel column chromatography of the urea concentrate. Total AA and EPA recoveries reached 39.5% and 50.8% respectively for a purity 97% for both fatty acids. Therefore, recovery of highly pure PUFA could be improved in organisms that are rich in two or more fatty acids of interest. The results of several procedures for AA and EPA recovery from several authors by using this microalga were compared.     

Pressurized extraction of unsaturated fatty acids and carotenoids from wet Chlorella vulgaris and Phaeodactylum tricornutum biomass using subcritical liquids

The objective of this study was to investigate the extraction of lipids, for example, mono‐ and polyunsaturated fatty acids (PUFA) as well as carotenoids, from wet microalgae biomass using pressurized subcritical extraction solvents, which meet the requirements of food and feed applications. To demonstrate the effect of the solvent and temperature on the lipid yield, we chose two microalgae species, viz. Chlorella vulgaris and Phaeodactylum tricornutum, differing in their biochemical composition fundamentally. In case of P. tricornutum, ethanol showed the highest fatty acid yield of 85.9% w/w. In addition to eicosapentaenoic acid (EPA), the ethanolic extracts contained exceptional amounts of fucoxanthin (up to 26.1 mg/g d. w.), which can be beneficial to protect unsaturated fatty acids from oxidation processes and in terms of human nutrition. For C. vulgaris, a fatty acid yield of 76.5% w/w was achieved from wet biomass using ethyl acetate at 150°C. In general, an increase in the extraction temperature up to 150°C was found to be important in terms of fatty acid yield when extracting wet microalgae biomass. The results suggest that it is possible to efficiently extract both fatty acids and carotenoids from wet microalgae by selecting suitable solvents and thus circumvent energy‐intensive drying of the biomass.     

Development of High‐Level Omega‐3 Eicosapentaenoic Acid (EPA) Production from Phaeodactylum tricornutum

Phaeodactylum tricornutum is a lipid‐rich marine diatom that contains a high level of omega‐3 polyunsaturated fatty acids, especially eicosapentaenoic acid (EPA). In an effort to reduce costs for large‐scale cultivation of this microalga, this study first established a New BBM medium (0.3 x strength BBM with only 3% of the initial phosphate level) to replace the traditional F/2 medium. Phaeodactylum tricornutum could grow in extremely low phosphate concentrations (25 µM), without compromising the EPA content. In the presence of sea salts, silicate addition was not necessary for high rate growth, high EPA content, or lipid accumulation in this species. Using urea as the sole nitrogen source tended to increase EPA contents per dry biomass (by 24.7%) while not affecting growth performance. The use of sea salts, rather than just sodium chloride, led to significantly improved biomass yields (20% increase) and EPA contents of total fatty acid (46–52% increase), most likely because it supplied sufficient essential elements such as magnesium. A salinity level of 35 led to significantly higher biomass yields compared with 20, but salinity had no significant influence on EPA content. EPA became the dominant fatty acid with average levels of 51.8% of total fatty acids during the exponential growth phase at 20 ppt in New BBM medium with sea salts.     

Production of eicosapentaenoic acid by the filamentous fungus Pythium irregulare

Because of the diversity of their lipids and fatty acid biosynthetic pathways, lower fungi may find utilization as sources of omega-3 or other polyunsaturated fatty acids (PUFA). Production of eicosapentaenoic acid (EPA) by the filamentous fungus, Pythium irregulare, has been demonstrated in 14-1 fermentors. Sweet whey permeate (lactose) was preferred over glucose as a substrate for production of a high-EPA-content lipid. Characterization of the lipid indicated that approximately 90% of the EPA was contained in the neutral lipid fraction. A specific productivity of 24.9 mg EPA/g dry biomass was achieved at 14°C, at which temperature the lipid contained 25.5% EPA and 54.2% PUFA. This is the highest mycelial EPA content for a fungal lipid that has been reported in the literature. Correspondence to: D. J. O'Brien     

The Production of Polyunsaturated Fatty Acids by Microalgae: from Strain Selection to Product Purification

A selection programme to increase the cellular eicosapentaenoic acid (EPA) content has been carried out with the microalga Isochrysis galbana. The selection process involved two stages of single selection. EPA content continuously increased from 2·4% dry weight (d.w.) of the ‘parent’ culture to an average value of 5·3% d.w. in the final stage. The proportion of total EPA variation attributable to the genetic variation (heritability in a broad sense) was 0·99 showing the importance of the genome in the determination of this fatty acid. The growth and fatty acid profile of an EPA-rich isolate grown as a chemostat in a cylindrical photobioreactor have been studied. A decrease in EPA content was observed (5·21% w/w to 2·8% w/w) at the lowest dilution rate D = 0·024 h⁻¹, up close to the maximum growth rate, D = 0·038 h⁻¹. At the same time, the biomass concentration also decreased from 1015 mg/litre to 202 mg/litre over the abovementioned range of dilution rate (D). Nonetheless, the EPA productivity increases with D, with a maximum of 15·26 mg/litre/day at D = 0·0208 h⁻¹. Furthermore, steady-state dilution rates may be related to average internal light intensity. Reverse-phase, high-pressure liquid chromatography (HPLC) on octadecylsilyl semi-preparative columns was used to separate stearidonic acid (SA), EPA and docosohexaenoic acid (DHA) in polyunsaturated fatty acid concentrate obtained by the urea complexation method from a fatty acid solution previously obtained by direct saponification of biomass. Isolate SA, EPA and DHA fraction purity was 94·8, 96·0 and 94·9%, respectively, with yields of 100·0, 99·6 and 94·0%.     

Enhancement of Polyunsaturated Fatty Acid Production by Tn5 Transposon in Shewanella baltica

Transposon Tn5 mutagenesis was used to generate random mutations in Shewanella baltica MAC1, a polyunsaturated fatty acid (PUFA)-producing bacterium. Three mutants produced 3–5 times more eicosapentaenoic acid (EPA 20:5 n−3) compared to the wild type at 10°C. One of the mutants produced 0.3 mg EPA g⁻¹ when grown at high temperature (30°C). Moreover, 2 mg docosahexaenoic acid (DHA 22:6 n−3) g⁻¹ was produced by S. baltica mutants at 4°C. Sequencing of insertion mutation(s) showed 96% homology to trimethylamine N-oxide (TMAO) reductase gene and 85% homology to rRNA operons of E. coli. Tn5 transposon mutagenesis therefore is a suitable technique to increase PUFA formation in bacteria.     

Optimisation of culture conditions for production of eicosapentaenoic acid byMortierella elongate NRRL 5513

Summary WhenMortierella elongata NRRL 5513 was cultured in shake flasks at 25°C, mycelial growth reached a stationary phase at 48 h but maximum eicosapentaenoic acid (EPA) production was observed at 6 days. When incubated at 11°C, EPA production also continued to rise during the stationary phase of growth, reaching a maximum after 10 days. An initial culture pH of 6.1 was found to be optimum for EPA production. The effect of temperature on EPA production was dependent on medium constituents. In glucose and linseed oil supplemented media, optimum temperature for EPA production was 11 and 15°C respectively. A maximum EPA yield of 0.61 g/l was obtained in linseed oil (2%), yeast extract (0.5%) supplemented basal medium. Maximum EPA content as a percentage of lipids (15.12%) was observed when the latter medium was supplemented with 0.25% urea.     

EFFECTS OF LOWERING TEMPERATURE DURING CULTURE ON THE PRODUCTION OF POLYUNSATURATED FATTY ACIDS IN THE MARINE DIATOM PHAEODACTYLUM TRICORNUTUM (BACILLARIOPHYCEAE)1

The composition of fatty acids and contents of eicosapentaenoic acid (EPA) and polyunsaturated fatty acids (PUFAs) of the economically important marine diatom, Phaeodactylum tricornutum (Bohlin), were investigated to see whether reducing the culture temperature enhances the production of EPA and PUFAs. The contents of EPA and PUFAs of P. tricornutum were found to be higher at lower temperature when cultured at 10, 15, 20, or 25°C. When the cells grown at 25°C were shifted to 20, 15, or 10°C, the contents per dry mass of PUFAs and EPA increased to the maximal values in 48, 24, and 12 h, respectively. The highest yields of PUFAs and EPA per unit dry mass (per unit volume of culture) were 4.9% and 2.6% (12.4 and 6.6 mg·L^?1), respectively, when temperature was shifted from 25 to 10°C for 12 h, both being raised by 120% compared with the control. The representative fatty acids in the total fatty acids, when temperature was lowered from 25 to 10°C, decreased proportionally by about 30% in C_16:0 and 20% in C_16:1(n?7) but increased about 85% in EPA. It was concluded that lowering culture temperature of P. tricornutum could significantly raise the yields of EPA and PUFAs.     

Plastidial acyl carrier protein Δ9-desaturase modulates eicosapentaenoic acid biosynthesis and triacylglycerol accumulation in Phaeodactylum tricornutum

The unicellular marine diatom Phaeodactylum tricornutum accumulates up to 35% eicosapentaenoic acid (EPA, 20:5n3) and has been used as a model organism to study long chain polyunsaturated fatty acids (LC-PUFA) biosynthesis due to an excellent annotated genome sequence and established transformation system. In P. tricornutum, the majority of EPA accumulates in polar lipids, particularly in galactolipids such as mono- and di-galactosyldiacylglycerol. LC-PUFA biosynthesis is considered to start from oleic acid (18:1n9). EPA can be synthesized via a series of desaturation and elongation steps occurring at the endoplasmic reticulum and newly synthesized EPA is then imported into the plastids for incorporation into galactolipids via an unknown route. The basis for the flux of EPA is fundamental to understanding LC-PUFA biosynthesis in diatoms. We used P. tricornutum to study acyl modifying activities, upstream of 18:1n9, on subsequent LC-PUFA biosynthesis. We identified the gene coding for the plastidial acyl carrier protein Δ9-desaturase, a key enzyme in fatty acid modification and analyzed the impact of overexpression and knock out of this gene on glycerolipid metabolism. This revealed a previously unknown role of this soluble desaturase in EPA synthesis and production of triacylglycerol. This study provides further insight into the distinctive nature of lipid metabolism in the marine diatom P. tricornutum and suggests additional approaches for tailoring oil composition in microalgae.     

Seasonal dynamics of long-chain polyunsaturated fatty acids in littoral benthos in the upper Yenisei river

We studied composition and concentrations of fatty acids (FAs) in benthos from pebbly littoral region of the Yenisei River in a sampling site near Krasnoyarsk city (Siberia, Russia) for 1 year from March 2003 to February 2004. Special attention was paid to major long-chain polyunsaturated fatty acids (PUFAs) of the ω3 family: eicosapentaenoic acid (EPA, 20:5ω3) and docosahexaenoic acids (DHA, 22:6ω3). In phytobenthos, which was dominated by diatoms, the annual maxima of EPA and DHA pool occurred in spring and early summer. In zoobenthos, EPA and DHA pool peaked in autumn, due mainly to an increase of the biomass of dominant taxa (gammarids) and to a moderate increase of the PUFA content per body weight. Seasonal peaks of EPA in overwintering insect larvae (chironomids and caddisflies) generally coincided with those of biomass of these larvae, while there was no such trend for amphipods and oligochaetes. In spring and early summer, the main part of ω3 PUFA, 40–97% of total amount, in the littoral region was contained in biomass of producers, i.e., benthic microalgae, and in autumn it was transferred to primary consumers—benthic invertebrates, which contained ∼76–93% of total ω3 PUFAs.     

Identification of Δ9-elongation activity from <Emphasis Type="Italic">Thraustochytrium aureum</Emphasis> by heterologous expression in <Emphasis Type="Italic">Pichia pastoris</Emphasis>

The Δ9-elongase isolated from Thraustochytrium aureum, which contains a high level of polyunsaturated fatty acids (PUFAs), was demonstrated to be associated with the synthesis of C20 PUFAs. The TaELO gene contains a 825 bp ORF that encodes a protein of 274 amino acids that shares a high similarity with other PUFA elongases. The expression of the TaELO gene in Pichia pastoris resulted in the elongation of linoleic acid (LA, C18:2; n-6) and α-linolenic acid (ALA, C18:3; n-3) to eicosadienoic acid (EDA, C20:2; n-6) and eicosatrienoic acid (ETrA, C20:3; n-3), respectively. The endogenous conversion rate of LA and ALA to EDA and ETrA was 32.68 and 38.57%, respectively. In addition, TaELO was also able to synthesize eicosenoic acid (C20:1; n-9) from oleic acid (OA, C18:1; n-9), even though the conversion level was low (2.81%). Furthermore, TaELO was able to carry out the 6Δ-elongation of γ-linolenic acid (GLA, C18:3; n-6) to dihomo-γ-linolenic acid (DGLA, C20:3; n-6) and Δ5-elongation of eicosapentaenoic acid (EPA, C20:5; n-3) to docosapentaenoic acid (DPA, C22:5; n-3). The conversion rate of GLA to DGLA and EPA to DPA were 93 and 28.36%, respectively. The TaELO protein was confirmed to have multifunctional activities, such as Δ9, Δ6, and Δ5-elongations as well as the elongation of monounsaturated fatty acid.     

Lipase-catalyzed esterification of glycerol and polyunsaturated fatty acids from fish and microalgae oils

This paper reports on the synthesis of triglycerides by enzymatic esterification of polyunsaturated fatty acids (PUFA) with glycerol. The lipase Novozym 435 (Novo Nordisk, A/S) from Candida antarctica was used to catalyze this reaction. The main factors influencing the degree of esterification and triglyceride yield were the amount of enzyme, water content, temperature and glycerol/fatty acid ratio. The optimum reaction conditions were established as: 100 mg of lipase; 9 ml hexane; 50°C; glycerol/PUFA concentrate molar ratio 1.2:3; 0% initial water; 1 g molecular sieves added at the start of reaction; and an agitation rate of 200 rpm. Under these conditions, a triglyceride yield of 93.5% was obtained from cod liver oil PUFA concentrate; the product contained 25.7% eicosapentaenoic acid and 44.7% docosahexaenoic acid. These optimized conditions were used to study esterification from a PUFA concentrate of the microalgae Phaeodactylum tricornutum and Porphyridium cruentum. With the first, a triglyceride yield of 96.5%, without monoglycerides and very few diglycerides, was obtained after 72 h of reaction; the resulting triglycerides had 42.5% eicosapentaenoic acid. A triglyceride yield of 89.3% was obtained from a P. cruentum PUFA concentrate at 96 h of reaction, which contained 43.4% arachidonic acid and 45.6% EPA. These high triglyceride yields were also achieved when the esterification reaction was scaled up 5-fold.     

Influence of biochemical,mineral and morphological features of natural food on tropical cladocerans

Five laboratory experiments were performed to evaluate the effect of supplements of fatty acids and a green alga on the individual growth and reproduction of three species of tropical cladocerans Ceriodaphnia richardi, Daphnia ambigua, and D. gessneri feeding on natural seston from the Brazilian Lake Monte Alegre. Cohorts of newborns from cultivated females were submitted to one of the following treatments: (1) Natural seston, (2) Natural seston + microcapsules of EPA and DHA or linoleic and linolenic fatty acids, (3) Natural seston + oil-free microcapsules, and (4) Natural seston + green alga Scenedesmus spinosus (1 mg C l⁻¹). Particulate organic carbon, algal carbon, C:P ratios of seston and green alga, polyunsaturated fatty acids (PUFA) content of seston and cladocerans, as well as phytoplankton composition, size, and shape were measured. The addition of fatty acids to seston did not significantly enhance growth and reproduction of the cladocerans, suggesting that sestonic PUFA content is sufficient for promoting cladoceran development, even in the cool–dry season when the fatty acids used in the experiments were 5–10 times lower in the seston than in the warm–wet season. Despite high C:P molar ratios in most experiments, there was only one indication of growth limitation by P. Reproduction was more affected than individual growth on some occasions by food quantity (energy) caused apparently by algal size, morphology, and digestion resistance. Energy availability, which is affected by algae morphological characteristics, seems to prevail over PUFA and P in controlling growth and reproduction of cladocerans in tropical Lake Monte Alegre.     

Interannual and between species comparison of the lipids, fatty acids and sterols of Antarctic krill from the US AMLR Elephant Island survey area

Antarctic euphausiids, Euphausia superba, E. tricantha, E. frigida and Thysanoessa macrura were collected near Elephant Island ¦ during 1997 and 1998. Total lipid was highest in E. superba small juveniles (16 mg g⁻¹ wet mass), ranging from 12 to 15 mg in other euphausiids. Polar lipid (56–81% of total lipid) and triacylglycerol (12–38%) were the major lipids with wax esters (6%) only present in E. tricantha. Cholesterol was the major sterol (80–100% of total sterols) with desmosterol second in abundance (1–18%). 1997 T. macrura and E. superba contained a more diverse sterol profile, including 24-nordehydrocholesterol (0.1–1.7%), trans-dehydrocholesterol (1.1–1.5%), brassicasterol (0.5–1.7%), 24-methylenecholesterol (0.1–0.4%) and two stanols (0.1–0.2%). Monounsaturated fatty acids included primarily 18:1(n−9)c (7–21%), 18:1(n−7)c (3–13%) and 16:1(n−7)c (2–7%). The main saturated fatty acids in krill were 16:0 (18–29%), 14:0 (2–15%) and 18:0 (1–13%). Highest eicosapentaenoic acid [EPA, 20:5(n−3)] and docosahexaenoic acid [DHA, 22:6(n−3)] occurred in E. superba (EPA, 15–21%; DHA, 9–14%), and were less abundant in other krill. E. superba is a good source of EPA and DHA for consideration of direct or indirect use as a food item for human consumption. Lower levels of 18:4(n−3) in E. tricantha, E. frigida and T. macrura (0.4–0.7% of total fatty acids) are more consistent with a carnivorous or omnivorous diet as compared with herbivorous E. superba (3.7–9.4%). The polyunsaturated fatty acid (PUFA) 18:5(n−3) and the very-long chain (VLC-PUFA), C₂₆ and C₂₈ PUFA, were not present in 1997 samples, but were detected at low levels in most 1998 euphausiids. Interannual differences in these biomarkers suggest greater importance of dinoflagellates or some other phytoplankton group in the Elephant Island area during 1998. The data have enabled between year comparisons of trophodynamic interactions of krill collected in the Elephant Island region, and will be of use to groups using signature lipid methodology.     

Isolation and structural characterisation of two antibacterial free fatty acids from the marine diatom, <Emphasis Type="Italic">Phaeodactylum tricornutum</Emphasis>

One solution to the global crisis of antibiotic resistance is the discovery of novel antimicrobial compounds for clinical application. Marine organisms are an attractive and, as yet, relatively untapped resource of new natural products. Cell extracts from the marine diatom, Phaeodactylum tricornutum, have antibacterial activity and the fatty acid, eicosapentaenoic acid (EPA), has been identified as one compound responsible for this activity. During the isolation of EPA, it became apparent that the extracts contained further antibacterial compounds. The present study was undertaken to isolate these additional antibacterial factors using silica column chromatography and reverse-phase high-performance liquid chromatography. Two antibacterial fractions, each containing a pure compound, were isolated and their chemical structures were investigated by mass spectrometry and nuclear magnetic resonance spectroscopy. The antibacterial compounds were identified as the monounsaturated fatty acid (9Z)-hexadecenoic acid (palmitoleic acid; C16:1 n-7) and the relatively unusual polyunsaturated fatty acid (6Z, 9Z, 12Z)-hexadecatrienoic acid (HTA; C16:3 n-4). Both are active against Gram-positive bacteria with HTA further inhibitory to the growth of the Gram-negative marine pathogen, Listonella anguillarum. Palmitoleic acid is active at micro-molar concentrations, kills bacteria rapidly, and is highly active against multidrug-resistant Staphylococcus aureus. These free fatty acids warrant further investigation as a new potential therapy for drug-resistant infections.     

Novel anti-inflammatory omega-3 PUFAs from the New Zealand green-lipped mussel, Perna canaliculus

The present study has identified in the marine mollusc, Perna canaliculus, an homologous series of novel omega 3 polyunsaturated fatty acids (ω-3 PUFA) with significant anti-inflammatory (AI) activity. The free fatty acid (FFA) class was isolated from a supercritical-CO₂ lipid extract of the tartaric acid-stabilised freeze-dried mussel powder by normal phase chromatography, followed by reversed-phase high performance liquid chromatography (RP–HPLC). The RP–HPLC involved separation based on carbon numbers, followed by argentation–HPLC (Ag–HPLC) of the methyl esters based on degree of unsaturation. Identification of the FFA components was performed using gas chromatography (GC) with flame ionisation detection, and individual structures were assigned by GC-mass spectroscopy (GC-MS). Inhibition of leukotriene production by stimulated human neutrophils was used as an in vitro screening method to test the AI activity of the purified PUFAs. A structurally related family of ω-3 PUFAs was identified in the most bioactive fractions, which included C18:4, C19:4, C20:4, and C21:5 PUFA. The C20:4 was the predominant PUFA in the extract, and was a structural isomer of arachidonic acid (AA). The novel compounds may be biologically significant as AI agents, as a result of their in vitro inhibition of lipoxygenase products of the AA pathway.     

Effect of nutrition on fatty acid profiles of riverine, lacustrine, and aquaculture-raised salmonids of pre-alpine habitats

We examined trophic positions and fatty acid concentrations of riverine, lacustrine, and aquaculture diet and fish in Austrian pre-alpine aquatic ecosystems. It was hypothesized that dietary fatty acid (FA) profiles largely influence the FA composition of the salmonids Salvelinus alpinus, Salmo trutta, and Oncorhynchus mykiss. We analyzed trophic positions using stable isotopes (δ¹⁵N) and tested for correlations with polyunsaturated fatty acid (PUFA) concentrations. Gut content analysis revealed benthos (rivers), pellets (aquaculture), and zooplankton (lakes) as the predominant diet source. Results of dorsal muscle tissues analysis showed that the omega-3 PUFA, docosahexaenoic acid (DHA; 22:6n − 3), was the mostly retained PUFA in all fish of all ecosystems, yet with the highest concentrations in S. alpinus from aquaculture (mean: 20 mg DHA/g dry weight). Moreover, we found that eicosapentaenoic acid (EPA; 20:5n − 3) in fish of natural habitats (rivers, lakes) was the second most abundant PUFA (3–5 mg/g DW), whereas aquaculture-raised fish had higher concentrations of the omega-6 linoleic acid (18:2n – 6; 9–11 mg/g DW) than EPA. In addition, PUFA patterns showed that higher omega-3/-6 ratios in aquacultures than in both riverine and lacustrine fish. Data of this pilot field study suggest that salmonids did not seem to directly adjust their PUFA to dietary PUFA profiles in either natural habitats or aquaculture and that some alterations of PUFA are plausible. Finally, we suggest that trophic positions of these freshwater salmonids do not predict PUFA concentrations in their dorsal muscle tissues.     

Associations of maternal prenatal dietary intake of n-3 and n-6 fatty acids with maternal and umbilical cord blood levels

Maternal n-3 and n-6 polyunsaturated fatty acid (PUFA) status may influence birth outcomes and child health. We assessed second trimester maternal diet with food frequency questionnaires (FFQs) (n=1666), mid-pregnancy maternal erythrocyte PUFA concentrations (n=1550), and umbilical cord plasma PUFA concentrations (n=449). Mean (SD) maternal intake of total n-3 PUFA was 1.17 g/d (0.43), docosahexaenoic and eicosapentaenoic acids (DHA+EPA) 0.16 g/d (0.17), and total n-6 PUFA 12.25 g/d (3.25). Mean maternal erythrocyte and cord plasma PUFA concentrations were 7.0% and 5.2% (total n-3), 5.0% and 4.6% (DHA+EPA), and 27.9% and 31.4% (total n-6). Mid-pregnancy diet–blood and blood–blood correlations were strongest for DHA+EPA (r=0.38 for diet with maternal blood, r=0.34 for diet with cord blood, r=0.36 for maternal blood with cord blood), and less strong for n-6 PUFA. The FFQ is a reliable measure of elongated PUFA intake, although inter-individual variation is present     

The effect of low temperature on fatty acid composition and tocopherols of the red microalga, <Emphasis Type="Italic">Porphyridium cruentum</Emphasis>

Porphyridium cruentum was grown in 10 L batch culture at 18°C, pH 8.0 and 28‰ salinity. The cells were harvested in the stationary phase and the fatty acid composition analysed by GC and tocopherol content by HPLC. A total of 14 fatty acids were identified including saturated fatty acids (13:0, 14:0, 14:0 iso, 15:0, 16:0, 16:0iso) and monounsaturated fatty acids (MUFAs; 16:1(n-7), 18:1(n-7), 18:1(n-9). Polyunsaturated fatty acids (PUFAs) were the predominant fatty acids detected, reaching 43.7% of total fatty acids in the stationary phase of culture. Among the PUFAs, eicosapentaenoic acid (EPA, 20:5(n-3)) was dominant (25.4%), followed by 12.8% arachidonic acid (AA, 20:4(n-6)). α-Tocopherol and γ-tocopherol contents were 55.2 μg g⁻¹ dry weight and 51.3 μg g⁻¹ dry weight respectively.