Fractionation of lipids and purification of γ-linolenic acid (GLA) from Spirulina platensis

Use of microalgal-fungal pellets for hydroponics effluent recycling and high-value biomass production

Hydroponic effluent (HE), enriched with inorganic nutrients, presents a viable, low-cost cultivation medium for microalgal biomass production and subsequent resource recovery. However, downstream processing, particularly biomass harvesting, remains a critical challenge for microalgal biorefineries. Therefore, the present study explored the potential of microalgal-fungal pellets (MAFP) in HE recycling for the production of biochemical-rich biomass. The optimized fungi-to-microalgae ratio (F:A) of 1:3 resulted in 100 % microalgal pelletization within 6 h. Surface characteristics suggested that metabolically active fungi with opposite charges facilitate microalgal pelletization. Further, MAFP exhibited a packed porous structure that was resilient to shear forces and had a high capacity for nutrient uptake. MAFP cultivation in HE demonstrated complete removal of ammonia-nitrogen (NH₃-N), phosphate (PO₄³⁻), and nitrate-nitrogen (NO₃⁻-N) within 7-9 days. The produced biomass was rich in biomolecules, including lipids (18.36 ± 0.12 % TS), protein (52.06 ± 2.1 % TS), and carbohydrates (28.95 ± 0.05 % TS). Besides, the high methane potential of MAFP (SMP ≈ 502.74 ± 19.1 mL CH4 g-1 VS, and TMP ≈ 817.68 ± 12.5 mL CH4 g-1 VS) indicated its suitability for biogas production. In essence, MAFP offers efficient HE recycling and biochemically rich biomass production, advancing towards a green and circular bioeconomy.

Effect of adding Spirulina platensis algae to small ruminant rations on productive, reproductive traits and some blood components

This experiment conducted using 20 Rahmani ewes at the last third of pregnancy in two equal groups. One group served as control, while the other group received Spirulina platensis (SP) at the rate of 0.5 gm 10 kg-1 live body weight. The objective was to find out the effect of adding Spirulina platensis algae to small ruminant rations on reproductive and productive traits and blood components of sheep. The experiments lasted for 120 days for both dams and their lambs after weaning. The findings proved that adding SP in ewes' diets had no effect on the average of live body weight change. Average milk yield was significantly (p <0.01) higher in the treatment group than the control. Lamb's birth weight and daily body gain of the treated group were significantly (p <0.01) higher than the control. Blood and serum picture profile of ewes were significantly higher when fed SP additive than the control. It could be concluded that the addition of SP to the ration of sheep positively preserved their health, productive and reproductive status as well as their lambs' growth rate. Also the additive improved the economic efficiency of treated animals by about 53.13%.

Chlorella vulgaris or Spirulina platensis mitigate lead acetate-induced testicular oxidative stress and apoptosis with regard to androgen receptor expression in rats

The current research was constructed to throw the light on the protective possibility of Chlorella vulgaris (C. vulgaris) and Spirulina platensis (S. platensis) against lead acetate-promoted testicular dysfunction in male rats. Forty rats were classified into four groups: (i) control, (ii) rats received lead acetate (30 mg/kg bw), (iii) rats concomitantly received lead acetate and C. vulgaris (300 mg/kg bw), (vi) rats were simultaneously treated with lead acetate and S. platensis (300 mg/kg bw) via oral gavage for 8 weeks. Lead acetate promoted testicular injury as expressed with fall in reproductive organ weights and gonadosomatic index (GSI). Lead acetate disrupted spermatogenesis as indicated by sperm cell count reduction and increased sperm malformation percentage. Lead acetate-deteriorated steroidogenesis is evoked by minimized serum testosterone along with maximized follicle-stimulating hormone (FSH) and luteinizing hormone (LH) levels. Testicular oxidative, inflammatory, and apoptotic cascades are revealed by elevated acid phosphatase (ACP) and sorbitol dehydrogenase (SDH) serum leakage, declined testicular total antioxidative capacity (TAC) with elevated total oxidative capacity (TOC), tumor necrosis factor alpha (TNF-α), caspase-3 levels, lessened androgen receptor (AR) expression, and histopathological lesions against control. Our research highlights that C. vulgaris or S. platensis therapy can modulate lead acetate-promoted testicular dysfunction via their antioxidant activity as expressed by elevated TAC and reduced TOC, immunomodulatory effect as indicated by lessened TNF-α level, and anti-apoptotic potential that was revealed by minimized caspase-3 levels. As well as restoration of testicular histoarchitecture, androgen receptor, steroidogenesis, and spermatogenesis were detected with better impacts to S. platensis comparing with C. vulgaris. Therefore, further clinical trials are needed to test S. platensis and C. vulgaris as a promising candidate in treating male infertility.

A Validated, Rapid and Cost-Efficient HPTLC Method for Quantification of Gamma-Linolenic Acid in Borage Oil and Evaluation of Antioxidant Activity

Borage oil that is extracted from (Borago officinalis Linn.) is a well-known medicinal plant having various medicinal benefits. In this work, an affordable, simple, reliable, rapid and easily accessible high-performance thin-layer chromatography (HPTLC) method was developed for the estimation of gamma-linolenic acid (GLA) in borage oil. HPTLC method employs thin-layer chromatography (TLC) aluminum plates precoated with silica gel (G60F254) as the stationary phase, and the mixture of hexane:toulene:glacial acetic acid (3:7:1, v/v/v) was used as the mobile phase. Densitometric analysis of the TLC plates was carried out at 200 nm. The developed method showed well-resolved spots with retention factor (Rf) value of 0.53 ± 0.04 for GLA. Various experimental conditions like saturation time for chamber, solvent phase migration and width of the band were studied intensely for selecting the optimum conditions. The method validation was performed for parameters like linearity, accuracy, specificity and precision. The values of limit of detection and limit of quantification for GLA were found to be 0.221 and 0.737 μg/band, respectively. In nutshell, the developed HPTLC method was found to be highly sensitive for the estimation of GLA in the herbal oil samples and formulations.

Effects of the substitution of soybean meal by spirulina in a hay-based diet for dairy cows on milk composition and sensory perception

The demand for protein sources alternative to soybean meal for supplementing forages low in metabolizable protein is large. The suitability of spirulina (Arthrospira platensis), a fast growing and resource-efficient blue-green microalga, as a source of metabolizable protein for dairy cows is known, but its effects on milk antioxidants and sensory properties were never investigated. Twelve cows were allocated to 2 groups and fed hay-based diets complemented with sugar beet pulp and wheat flakes in individual feeding troughs. The N content per kilogram of DM was equivalent between the 2 diets. Diet of 1 group was supplemented with 5% spirulina; the second group was supplemented with 6% soybean meal (control). After an adaptation period of 15 d, data were collected, and feed, milk, blood, and rumen fluid were sampled. Feeds were analyzed for proximate contents, and blood plasma was analyzed for total antioxidant capacity and antioxidant contents (tocopherol, phenols). Milk samples were analyzed for fatty acid profile, coagulation properties, color, and contents of fat, protein, lactose, total phenols, lipophilic vitamins, and provitamins (e.g., β-carotene). Triangle tests were performed by a trained sensory panel on 6 homogenized and pasteurized bulk milk samples per treatment. The substitution of soybean meal by spirulina in the diet did not affect feed intake, milk yield, milk fat, protein, or lactose contents compared with the control group. However, the milk from the spirulina-fed cows had a higher content of β-carotene (0.207 vs. 0.135 μg/mL) and was more yellow (b* index: 14.9 vs. 13.8). Similar to the spirulina lipids but far less pronounced, the milk fat from the spirulina-fed cows had a higher proportion of γ-linolenic acid (0.057 vs. 0.038% of fatty acid methyl esters) compared with milk fat from soybean meal-fed cows. Also trans-11 C18:1 (vaccenic acid) and other C18:1 trans isomers were elevated, but otherwise the fatty acid profile resembled that of cows fed the control diet. No sensory difference was found between milk from the 2 experimental groups. Furthermore, we observed no effects of substituting soybean meal by spirulina on total antioxidant capacity, α-tocopherol and total phenols in blood and milk. Effects on rumen fluid characteristics were minor. In conclusion, spirulina seems to be a promising protein source for dairy cows with certain improvements in nutritionally favorable constituents in milk and without side-effects on animal performance in the short term.

Maternal Spirulina supplementation during pregnancy and lactation partially prevents oxidative stress, glial activation and neuronal damage in protein malnourished F1 progeny

Protein malnutrition (PMN) is a global health issue but most prevalent in Africa and Asia. It exerts detrimental effect on structural and physiological aspects of hippocampal circuitry. Despite accumulating evidence for PMN induced changes in nervous system, relatively very little is known about how maternal nutritional supplementation during malnutrition affects glial cells and neurons. Herein, we aimed to investigate the effects of maternal Spirulina supplementation against PMN induced oxidative stress, reactive gliosis and neuronal damage in hippocampus of F1 progeny. Three months old healthy Sprague Dawley females (n = 24) were shifted to normoprotein (NC; 20% protein) and low protein (LP; 8% protein) diets 15 days before conception. The NC and LP group females were subdivided into two groups according to Spirulina supplementation (400 mg/kg/b.wt. orally throughout gestation and lactation period): normal control with Spirulina (NC SPI) and low protein with Spirulina supplemented group (LP SPI). F1 progeny born were used in present study. Thus, building on earlier results of ameliorated neurobehavioral and cognitive abilities in Spirulina supplemented protein deprived rats, the present study incorporates neurochemical and morphometric analysis of glial cells and neurons and revealed that maternal Spirulina consumption partially prevented the PMN associated neuropathological alterations in terms of attenuated oxidative brain damage, reduced reactive gliosis and apoptotic cell population, improved dendritic branch complexity with few damaged neurons and enhanced mushroom shaped spine density. The results suggest that cellular changes in hippocampus after PMN are partially restored after maternal Spirulina supplementation and one could envision intervention approaches using Spirulina against malnutrition.

Preparative supercritical fluid chromatography for lipid class fractionation-a novel strategy in high-resolution mass spectrometry based lipidomics

In this work, a lipidomics workflow based on offline semi-preparative lipid class-specific fractionation by supercritical fluid chromatography (SFC) followed by high-resolution mass spectrometry was introduced. The powerful SFC approach offered separation of a wide polarity range for lipids, enabled enrichment (up to 3 orders of magnitude) of lipids, selective fractionation of 14 lipid classes/subclasses, and increased dynamic range enabling in-depth characterization. A significantly increased coverage of low abundant lipids improving lipid identification by numbers and degree (species and molecular level) was obtained in Pichia pastoris when comparing high-resolution mass spectrometry based lipidomics with and without prior fractionation. Proof-of-principle experiments using a standard reference material (SRM 1950, NIST) for human plasma showed that the proposed strategy enabled quantitative lipidomics. Indeed, for 70 lipids, the consensus values available for this sample could be met. Thus, the novel workflow is ideally suited for lipid class-specific purification/isolation from milligram amounts of sample while not compromising on omics type of analysis (identification and quantification). Finally, compared with established fractionation/pre-concentration approaches, semi-preparative SFC is superior in terms of versatility, as it involved only volatile modifiers and salt additives facilitating any follow-up use such as qualitative or quantitate analysis or further purification down to the single lipid species level. Graphical Abstract.

Amelioration of neurobehavioral and cognitive abilities of F1 progeny following dietary supplementation with Spirulina to protein malnourished mothers

Early life adversities (stress, infection and mal/undernutrition) can affect neurocognitive, hippocampal and immunological functioning of the brain throughout life. Substantial evidence suggests that maternal protein malnutrition contributes to the progression of neurocognitive abnormalities and psychopathologies in adolescence and adulthood in offspring. Maternal malnutrition is prevalent in low and middle resource populations. The present study was therefore undertaken to evaluate the effects of dietary Spirulina supplementation of protein malnourished mothers during pregnancy and lactation on their offspring's reflex, neurobehavioral and cognitive development. Spirulina is a Cyanobacterium and a major source of protein and is being used extensively as a dynamic nutraceutical against aging and neurodegeneration. Sprague Dawley rats were switched to low protein (8% protein) or normal protein (20% protein) diet for 15 days before conception. Spirulina was orally administered (400 mg/kg/b.wt.) to subgroups of pregnant females from the day of conception throughout the lactational period. We examined several parameters including reproductive performance of dams, physical development, postnatal reflex ontogeny, locomotor behavior, neuromuscular strength, anxiety, anhedonic behavior, cognitive abilities and microglia populations in the F1 progeny. The study showed improved reproductive performance of Spirulina supplemented protein malnourished dams, accelerated acquisition of neurological reflexes, better physical appearance, enhanced neuromuscular strength, improved spatial learning and memory and partly normalized PMN induced hyperactivity, anxiolytic and anhedonic behavior in offspring. These beneficial effects of Spirulina consumption were also accompanied by reduced microglial activation which might assist in restoring the behavioral and cognitive skills in protein malnourished F1 rats. Maternal Spirulina supplementation is therefore proposed as an economical nutraceutical/supplement to combat malnutrition associated behavioral and cognitive deficits.

Extraction of Dairy Phospholipids Using Switchable Solvents: A Feasibility Study

A tertiary amine (N,N-dimethylcyclohexylamine, CyNMe2) was used as a switchable hydrophilicity solvent (SHS) for extracting phospholipids (PLs) from raw cream (RC), buttermilk (BM), concentrated buttermilk (CBM), and beta-serum (BS). The SHS extractions were performed with varying solvent-sample weight ratio at room temperature. The extracted PLs using CyNMe2 were recovered by bubbling CO₂ at atmospheric pressure, switching the CyNMe2 into its respective salt. For comparison, the PLs were also extracted using Folch (FE) and Mojonnier (ME) extraction. The extraction efficiency of SHS varied from 0.33% to 99%, depending on the type of byproduct. The SHS extracted up to 99% of the PLs directly from BM, while only 11.37% ± 0.57% and 2.66% ± 0.56% of the PLs were extracted with FE and ME, respectively. These results demonstrate the applicability of SHS for the extraction of PLs from dairy byproducts.

Solid Matrix-Supported Supercritical CO₂ Enhances Extraction of γ-Linolenic Acid from the Cyanobacterium Arthrospira (Spirulina) platensis and Bioactivity Evaluation of the Molecule in Zebrafish

Marine cyanobacteria represent a large untapped source of functional glycolipids enriched with polyunsaturated fatty acids (PUFAs) for human health. However, advanced methods for scalable isolation of diverse species containing high-purity PUFA-rich glycolipids will have to be developed and their possible pharmaceutical and nutraceutical functions identified. This paper introduces a novel solid matrix-supported supercritical CO₂ extraction method for scalable isolation of the PUFA γ-linolenic acid (GLA)-enriched glycolipids from the cyanobacterium Arthrospira (Spirulina) platensis, which has been the most widely used among microalgae in the nutraceutical and pharmaceutical industries. Of various porous materials studied, diatomite was the best to facilitate extraction of GLA-rich glycolipids, resulting in an extraction efficiency of 98%. Gamma-linolenic acid made up 35% of total fatty acids (TFAs) in the extracts, which was considerably greater than that obtained with ethanol (26%), Bligh and Dyer (24%), and in situ transesterification (24%) methods, respectively. Lipidomics analysis revealed that GLA was exclusively associated with galactolipids. Pharmaceutical functions of GLA-rich galactolipids were investigated on a zebrafish caudal fin regeneration model. The results suggested that GLA extracted from A. platensis possessed anti-oxidative, anti-inflammatory, and anti-allergic activities, which acted in a concerted manner to promote post-injury regeneration of zebrafish.

Algal Proteins: Extraction, Application, and Challenges Concerning Production

Population growth combined with increasingly limited resources of arable land and fresh water has resulted in a need for alternative protein sources. Macroalgae (seaweed) and microalgae are examples of under-exploited "crops". Algae do not compete with traditional food crops for space and resources. This review details the characteristics of commonly consumed algae, as well as their potential for use as a protein source based on their protein quality, amino acid composition, and digestibility. Protein extraction methods applied to algae to date, including enzymatic hydrolysis, physical processes, and chemical extraction and novel methods such as ultrasound-assisted extraction, pulsed electric field, and microwave-assisted extraction are discussed. Moreover, existing protein enrichment methods used in the dairy industry and the potential of these methods to generate high value ingredients from algae, such as bioactive peptides and functional ingredients are discussed. Applications of algae in human nutrition, animal feed, and aquaculture are examined.

Uncovering Potential Applications of Cyanobacteria and Algal Metabolites in Biology, Agriculture and Medicine: Current Status and Future Prospects

Cyanobacteria and algae having complex photosynthetic systems can channelize absorbed solar energy into other forms of energy for production of food and metabolites. In addition, they are promising biocatalysts and can be used in the field of "white biotechnology" for enhancing the sustainable production of food, metabolites, and green energy sources such as biodiesel. In this review, an endeavor has been made to uncover the significance of various metabolites like phenolics, phytoene/terpenoids, phytols, sterols, free fatty acids, photoprotective compounds (MAAs, scytonemin, carotenoids, polysaccharides, halogenated compounds, etc.), phytohormones, cyanotoxins, biocides (algaecides, herbicides, and insecticides) etc. Apart from this, the importance of these metabolites as antibiotics, immunosuppressant, anticancer, antiviral, anti-inflammatory agent has also been discussed. Metabolites obtained from cyanobacteria and algae have several biotechnological, industrial, pharmaceutical, and cosmetic uses which have also been discussed in this review along with the emerging technology of their harvesting for enhancing the production of compounds like bioethanol, biofuel etc. at commercial level. In later sections, we have discussed genetically modified organisms and metabolite production from them. We have also briefly discussed the concept of bioprocessing highlighting the functioning of companies engaged in metabolites production as well as their cost effectiveness and challenges that are being addressed by these companies.

Quantification of Phytochemicals from Commercial Spirulina Products and Their Antioxidant Activities

The present study aimed to profile the polyunsaturated fatty acids, sugars, free amino acids, and polyphenols in 37 varieties of Spirulina commonly available in the market using gas chromatography and high performance liquid chromatography. In addition, the biological potentials of the Spirulina samples were evaluated by analysing the in vitro antioxidant activities using various analytical techniques. The analyses revealed the presence of 13 polyunsaturated fatty acids, 18 amino acids, 7 sugars, and polyphenols. The polyunsaturated fatty acids contents were varied between Spirulina samples. The total polyunsaturated fatty acids amount was 4.25 mg/100 g, and the average among of sapienic acid detected was 2.25 mg/100 g, which was followed by linoleic acid (16.7%) and γ-linolenic acid (14%). Among the 7 sugars, the hexose levels were the highest (73.85%). The total amino acids contents ranged from 11.49 to 56.14 mg/100 g, and the individual essential amino acids accounted for 17% to 39.18%. The “natural” tablets exhibited the highest polyphenols levels (24 mg/g). All of the Spirulina samples expressed dose-dependent antioxidant activities. The polyunsaturated fatty acids, sugars, free amino acids, and polyphenols contents varied widely, and the variations in these compounds between the Spirulina samples were significant.

P. D, M. V. N. L. C. Isolation of methyl gamma linolenate from Spirulina platensis using flash chromatography and its apoptosis inducing effect

Background

Isolation of methyl gamma linolenate from Spirulina platensis using flash chromatography and its apoptosis inducing effect against human lung carcinoma A- 549 cell lines.

Methods

Gamma linolenic acid is an important omega-6 polyunsaturated fatty acid (PUFA) of medicinal interest was isolated from microalgae Spirulina platensis using flash chromatography system (Isolera system) as its methyl ester. The isolated methyl gamma linolenate was characterized by IR, ¹H NMR, ¹³C NMR and mass spectral analysis and the data were consistent with the structure.

Results

The percentage yield of isolated methyl gamma linolenate is found to be 71 % w/w, which is a very good yield in comparison to other conventional methods. It was subjected to in-vitro cytotoxic screening on A-549 lung cancer cell lines using SRB assay and result was compared with standard rutin.

Conclusion

It may be concluded that the Flash chromatography system plays a major role in improving the yield for theisolation of methyl gamma linoleate from Spirulina platensis and the isolated molecule is a potent cytotoxicagent towards human lung carcinoma cell lines, however it may be further taken up for an extensive study.

Synthesis and characterization of some novel fatty acid analogues: a preliminary investigation on their activity against human lung carcinoma cell line

BACKGROUND

Preparation of some novel heterocyclic compounds with long alkyl and alkenyl chain of cytotoxic activity.

METHODS

Gamma linolenic acid, a poly unsaturated fatty acid and stearic acid, a saturated fatty acid were isolated from the microalga Spirulina platensis. Some novel gamma linolenic acid and stearic acid analogues having 1,3,4-oxadiazole and 1,2,4-triazole were synthesized and characterized by IR, 1H NMR, 13C NMR and mass spectral analysis. Cytotoxicity of these compounds was evaluated by the growth inhibition of A-549 cells in-vitro.

RESULTS

Compound 1 and 3 showed comparable cytotoxicity against the human lung carcinoma A-549 cell lines.

Synthesis, antidepressant and antimicrobial activities of some novel stearic acid analogues

Stearic acid, a saturated fatty acid was isolated from the microalga Spirulina platensis. Some novel stearic acid analogues having 1,3,4-oxadiazole, 1,2,4-triazole and 1,2,4-triazolo-[3,4-b]-1,3,4-thiadiazole are synthesized and characterized by IR, NMR and mass spectral analysis. All the synthesized compounds were screened for antimicrobial activity by using cup plate method. The synthesized compounds have been further screened for their antidepressant activity in swiss albino mice by forced swim test (FST), midbrain dopamine has been estimated and quantified. All the compounds showed good antimicrobial activity and compound 6 showed significant antidepressant activity.

Low-parachor solvents extraction and thermostated micro-thin-layer chromatography separation for fast screening and classification of spirulina from pharmaceutical formulations and food samples

The goal of this paper is to demonstrate the separation and detection capability of eco-friendly micro-TLC technique for the classification of spirulina and selected herbs from pharmaceutical and food products. Target compounds were extracted using relatively low-parachor liquids. A number of the spirulina samples which originated from pharmaceutical formulations and food products, were isolated using a simple one step extraction with small volume of methanol, acetone or tetrahydrofuran. Herb samples rich in chlorophyll dyes were analyzed as reference materials. Quantitative data derived from micro-plates under visible light conditions and after iodine staining were explored using chemometrics tools including cluster analysis and principal components analysis. Using this method we could easily distinguish genuine spirulina and non-spirulina samples as well as fresh from expired commercial products and furthermore, we could identify some biodegradation peaks appearing on micro-TLC profiles. This methodology can be applied as a fast screening or fingerprinting tool for the classification of genuine spirulina and herb samples and in particular may be used commercially for the rapid quality control screening of products. Furthermore, this approach allows low-cost fractionation of target substances including cyanobacteria pigments in raw biological or environmental samples for preliminary chemotaxonomic investigations. Due to the low consumption of the mobile phase (usually less than 1 mL per run), this method can be considered as environmentally friendly analytical tool, which may be an alternative for fingerprinting protocols based on HPLC machines and simple separation systems involving planar micro-fluidic or micro-chip devices.

Microalgae for "Healthy" Foods-Possibilities and Challenges

  Microalgae have the potential to become a novel source of bioactive molecules, especially for those who might wish to enhance the nutritional and functional quality of foods. Spirulina, one of the most popular microalgae, has been described by the World Health Organization as one of the greatest superfoods on earth serving as an example of the potential of microalgae. This review provides background on current and future uses of microalgae in the human diet, lists the most common species of microalgae used to this end, and describes some production methods used in research and industrial production and recovery. The review also discusses some of the difficulties so far encountered such as low productivities and recovery rates, as well as challenges in the production of compounds of interest. Many scientists and engineers in research centers around the globe are currently dedicated to solve these problems as the various capabilities of microalgae have caught the attention of the energy, environmental, and agricultural industries, we propose that the food industry should as well evaluate the potential of microalgae as a novel source of "health promoting" compounds.

Supercritical fluid extraction: Recent advances and applications

Among the different extraction techniques used at analytical and preparative scale, supercritical fluid extraction (SFE) is one of the most used. This review covers the most recent developments of SFE in different fields, such as food science, natural products, by-product recovery, pharmaceutical and environmental sciences, during the period 2007-2009. The revision is focused on the most recent advances and applications in the different areas; among them, it is remarkable the strong impact of SFE to extract high value compounds from food and natural products but also its increasing importance in areas such as heavy metals recovery, enantiomeric resolution or drug delivery systems.

Recent trends in the advanced analysis of bioactive fatty acids

The consumption of dietary fats have been long associated to chronic diseases such as obesity, diabetes, cancer, arthritis, asthma, and cardiovascular disease; although some controversy still exists in the role of dietary fats in human health, certain fats have demonstrated their positive effect in the modulation of abnormal fatty acid and eicosanoid metabolism, both of them associated to chronic diseases. Among the different fats, some fatty acids can be used as functional ingredients such as alpha-linolenic acid (ALA), arachidonic acid (AA), eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), gamma-linolenic acid (GLA), stearidonic acid (STA) and conjugated linoleic acid (CLA), among others. The present review is focused on recent developments in FAs analysis, covering sample preparation methods such as extraction, fractionation and derivatization as well as new advances in chromatographic methods such as GC and HPLC. Special attention is paid to trans fatty acids due its increasing interest for the food industry.

Predictive modeling of biomass production by Spirulina platensis as function of nitrate and NaCl concentrations

Effects of nitrate (2.0, 2.5, and 3.0 g L(-1)) and salt (0.5, 1.0, 1.5, 2.0 g L(-1)) concentrations on biomass production by Spirulinaplatensis was examined in the Schlösser medium. The highest (p<0.001) biomass yields and chlorophyll a content was observed at 2.5 g L(-1) nitrate and 1.5 g L(-1) NaCl as 3.495 g L(-1) and 29.92 mg L(-1), respectively. Increment rate of biomass production was especially found between 72 and 216 h. Modified Richards, Schnute, Logistic and Gompertz models was successfully predicted (r(2)>0.96 and RSS0.003) biomass production by S.platensis as function of nitrate and salt concentrations. Low residual sum of squares (RSS) and high regression coefficients (r(2)) indicated that used models were well fitted to the experiment data and it could be regarded as sufficient to describe biomass production of Spirulina sp. Biological variables i.e. production rate (micro) and lag time (lambda) for S.platensis ranged 0.012-0.034 h(-1) and 2.43-5.85 h, respectively from biomass production were successfully predicted by modified Logistic model according to low RSS and F-testing value.