Changes in fatty acids, amino acids and carbon/nitrogen biomass during nitrogen starvation of ammonium- and nitrate-grownIsochrysis galbana

Flynn, Kevin J.; Garrido, J. L.; Zapata, Manuel; Öpik, Helgi; Hipkin, C. R.

doi:10.1007/bf02442457

Cited by 37 publications

(33 citation statements)

References 18 publications

(16 reference statements)

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“…In our research, sufficient N reduced the lipid accumulation as well as FA content (Table 1), probably because the division of algae was so vigorous that the lipid accumulation was suppressed. Flynn implied that under low light intensity (40 lmol/m 2 s), sufficient N could enhance the activity of fatty acid desaturase, thus resulting in higher ratio of UFA/TFA ratio comparing to other cultures, which was in keeping with our experiment conducted under 80 lmol/m 2 s although the influence of extra N was weaken by higher light intensity (Flynn et al, 1992). CM provided the highest UFA content of 7.476% and UFA/TFA ratio under 320 lmol/m 2 s, suggesting that the condition was beneficial for the production of UFA.…”

Section: The Effect Of Light Intensity and Different Cultures On Fa Csupporting

confidence: 86%

Light intensity and N/P nutrient affect the accumulation of lipid and unsaturated fatty acids by Chlorella sp.

Guo

Zheng

et al. 2015

Bioresource Technology

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Section: The Effect Of Light Intensity and Different Cultures On Fa Csupporting

confidence: 86%

Light intensity and N/P nutrient affect the accumulation of lipid and unsaturated fatty acids by Chlorella sp.

Guo

Zheng

et al. 2015

Bioresource Technology

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“…Mean NPN concentrations were 70, 86, 47 and 110 g/kg DM, which equals 10%, 16%, 11% and 25% of CP for Arthrospira , Chlorella , Nannochloropsis and Phaeodactylum respectively. Among others, NPN compounds in microalgae can be free AA (Al‐Amoudi & Flynn, ; Dortch, Clayton, Thoresen, & Ahmed, ; Flynn, Garrido, Zapata, Öpik, & Hipkin, ), nucleic acids (Dortch et al., ; Lourenço, Barbarino, Marquez, & Aidar, ; Lourenço et al., ) and nitrogenous pigments, such as chlorophylls (Lourenço et al., , ). Furthermore, NPN compounds can originate from intracellular inorganic nitrogenous compounds, such as nitrate, nitrite and ammonium (Dortch, ; Dortch et al., ; Lourenço et al., , ).…”

Section: Resultsmentioning

confidence: 99%

Variability in nutrient composition and in vitro crude protein digestibility of 16 microalgae products

Wild

Steingaß

Rodehutscord

2018

Animal Physiology Nutrition

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The chemical composition of 16 microalgae products of four genera, Arthrospira (n = 2), Chlorella (n = 8), Nannochloropsis (n = 4) and Phaeodactylum (n = 2), was assayed to evaluate the intra- and inter-genera variation of nutrient profiles of commercial microalgae products. Crude protein was the main component in all genera, followed by ether extract and crude ash. Mean crude protein concentrations were 690, 502, 431 and 446 g/kg dry matter, and mean ether extract concentrations were 63, 157, 188 and 113 g/kg dry matter for Arthrospira, Chlorella, Nannochloropsis and Phaeodactylum respectively. However, there was considerable inter- and intra-genera variation. The concentration of α-linked glucose was low (0-143 g/kg dry matter). There was high variation between and within genera in the crude ash concentration (22-237 g/kg dry matter), which was also observed for the mineral composition. In contrast to the crude protein concentration, the amino acid composition of the protein (g amino acid/16 g N) was less variable. The investigated samples possessed high concentrations of Glx, Asx and Leu, and low concentrations of Cys and Met. The mean concentration of non-protein nitrogen compounds was highest in Phaeodactylum (110 g/kg dry matter) and lowest in Nannochloropsis (47 g/kg dry matter) products, and as with proximate nutrients, high variability between and within genera was observed. In vitro crude protein digestibility varied between 54% (non-cell-disrupted Nannochloropsis) and 84% (cell-disrupted Chlorella). Inositol phosphate isomers were not detectable in any sample (concentration <1 μmol/g dry matter). The predominant fatty acids were C16:0 in Arthrospira products, C18:2 n-6+ C19:1 t7 and C18:3 n-3 in Chlorella products, and C20:5 n-3 in Nannochloropsis and Phaeodactylum products; however, the relative proportions of fatty acids varied within genera. Commercially available microalgae products appear to be valuable alternative food and feed products. However, because of the high variability in nutrient profiles, attention should be given to the analytical characterization of the products.

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“…Cell counts were made by haemocytometer (improved Neubauer). Details for measuring intracellular amino acids by high-performance liquid chromatography (HPLC) C-N biomass and ultrastructural examination are given in Flynn et al (1992). For pigment analysis, 25 ml volumes were filtered under low vacuum and immediately frozen.…”

Section: Methodsmentioning

confidence: 99%

Changes in carbon and nitrogen physiology during ammonium and nitrate nutrition and nitrogen starvation inIsochrysis galbana

Flynn

Zapata

Garrido

et al. 1993

European Journal of Phycology

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Isochrysis galbana was grown in a 12/12 h light/dark cycle with either nitrate or ammonium as the N-source, and then resuspended in N-flee medium. During exponential growth ammonium-growing cells contained half the fatty acid content, higher concentrations of intracellular free glutamine and asparagine, and little nitrate reductase activity in comparison with nitrate-growing cells. Differences in the glutamine/glutamate and asparagine/aspartate ratios suggest that nitrate-growing cells were relatively more N-stressed than ammoniumgrowing cells. During N-starvation the fatty acid content of ammonium-grown cells increased to levels similar to those in nitrate-grown cells and the proportion of oleic acid increased in both cultures. Possible reasons for the increased synthesis of fatty acids, with its additional demand for reductant, in cells growing on nitrate N are discussed. Nitrate reductase activity remained low in the ammoniumgrown cells and decreased rapidly in the nitrate-grown cells during N-starvation. Net chlorophyll synthesis ceased within 36 h of the start of N-deprivation but synthesis of some carotenoids continued, with proportions of echinenone increasing and fucoxanthin decreasing. The ratio of chlorophyll a to c was the same in both cultures and remained constant during N-deprivation. Electron microscopy showed increasing numbers of lipid bodies in the cells during N-starvation and the cells reacted to fixation by swelling, possibly because of decreased protein content in membranes.

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Changes in fatty acids, amino acids and carbon/nitrogen biomass during nitrogen starvation of ammonium- and nitrate-grownIsochrysis galbana

Cited by 37 publications

References 18 publications

Light intensity and N/P nutrient affect the accumulation of lipid and unsaturated fatty acids by Chlorella sp.

Light intensity and N/P nutrient affect the accumulation of lipid and unsaturated fatty acids by Chlorella sp.

Variability in nutrient composition and in vitro crude protein digestibility of 16 microalgae products

Changes in carbon and nitrogen physiology during ammonium and nitrate nutrition and nitrogen starvation inIsochrysis galbana

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