Limits...
Potential of lipid metabolism in marine diatoms for biofuel production.

d'Ippolito G, Sardo A, Paris D, Vella FM, Adelfi MG, Botte P, Gallo C, Fontana A - Biotechnol Biofuels (2015)

Bottom Line: The effect was less pronounced in cultures where silicon was reduced to 20% of the standard supply.Nitrogen limitation did not affect growth rates but led to lipid remodeling and de novo synthesis of triacylglycerols.Triacylglycerols in T. weissflogii and C. cryptica can account for up to 82% and 88% of total glycerolipids, thereby suggesting that the two species are promising candidates for large-scale experimentation for biofuel production.

View Article: PubMed Central - PubMed

Affiliation: Istituto di Chimica Biomolecolare (ICB) - CNR, Via Campi Flegrei 34, 80078 Pozzuoli, NA Italy.

ABSTRACT

Background: Diatoms are an ecologically relevant group of microalgae that are not commonly considered for bio-oil production even if they are responsible for massive blooms at sea. Seventeen diatom species were screened for their capacity to produce biomass and lipids, in relation to their growth rate. Triglyceride levels were also assessed as a preferential source of biofuels.

Results: Using statistical analysis, two centric diatoms, Thalassiosira weissflogii and Cyclotella cryptica, were selected as good candidates for oil production. Lipid levels significantly increased when the two diatoms were cultivated in a two-stage process under nitrogen limitation. The effect was less pronounced in cultures where silicon was reduced to 20% of the standard supply. Nitrogen limitation did not affect growth rates but led to lipid remodeling and de novo synthesis of triacylglycerols.

Conclusions: Triacylglycerols in T. weissflogii and C. cryptica can account for up to 82% and 88% of total glycerolipids, thereby suggesting that the two species are promising candidates for large-scale experimentation for biofuel production.

No MeSH data available.


Cultures of T. weissflogii P09 and C. cryptica CCMP 331 under two-stage nutrient regime. (A) Growth curves during the first (from day 0 to day 6) and second (from day 6 to day 11) stage of growth for Thalassiosira weissflogii . Gray lines indicate nutrient consumption under replete conditions; (B) growth curves during the first (from day 0 to day 8) and second (from day 8 to day 14) stage of growth for C. cryptica. Gray lines indicate nutrient consumption under replete conditions; (C) growth curve and nutrient consumption under depleted conditions (second stage of growth) for Thalassiosira weissflogii P09; (D) growth curve and nutrient consumption under depleted conditions (second stage of growth) for C. cryptica.
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Fig2: Cultures of T. weissflogii P09 and C. cryptica CCMP 331 under two-stage nutrient regime. (A) Growth curves during the first (from day 0 to day 6) and second (from day 6 to day 11) stage of growth for Thalassiosira weissflogii . Gray lines indicate nutrient consumption under replete conditions; (B) growth curves during the first (from day 0 to day 8) and second (from day 8 to day 14) stage of growth for C. cryptica. Gray lines indicate nutrient consumption under replete conditions; (C) growth curve and nutrient consumption under depleted conditions (second stage of growth) for Thalassiosira weissflogii P09; (D) growth curve and nutrient consumption under depleted conditions (second stage of growth) for C. cryptica.

Mentions: As shown in Figure 2, the two diatoms consumed both silicon and nitrogen at different extent during the exponential growth phase. In agreement with the literature [30-32], after 2 days, silicon had diminished to close to zero, whereas nitrogen levels had decreased more slowly but were nonetheless reduced to one third of the starting supply by the time cells had entered the stationary phase (6 days for T. weissflogii P09 and 8 days for C. cryptica) (Figure 2A,B). A similar response was also recorded during the second stage of growth when cultures were gently centrifuged and re-suspended in both replete and nutrient-limited media. Since silicon is an essential nutrient for diatoms [33], it was immediately incorporated when added to the medium, independently of the culture conditions of both species (Figure 2C,D). On the other hand, nitrogen was consumed to a small extent in Si-deprived cultures. Interestingly, the two species responded differently to Si limitation, since C. cryptica grew better than T. weissflogii P09 when Si was reduced or absent in the medium.Figure 2


Potential of lipid metabolism in marine diatoms for biofuel production.

d'Ippolito G, Sardo A, Paris D, Vella FM, Adelfi MG, Botte P, Gallo C, Fontana A - Biotechnol Biofuels (2015)

Cultures of T. weissflogii P09 and C. cryptica CCMP 331 under two-stage nutrient regime. (A) Growth curves during the first (from day 0 to day 6) and second (from day 6 to day 11) stage of growth for Thalassiosira weissflogii . Gray lines indicate nutrient consumption under replete conditions; (B) growth curves during the first (from day 0 to day 8) and second (from day 8 to day 14) stage of growth for C. cryptica. Gray lines indicate nutrient consumption under replete conditions; (C) growth curve and nutrient consumption under depleted conditions (second stage of growth) for Thalassiosira weissflogii P09; (D) growth curve and nutrient consumption under depleted conditions (second stage of growth) for C. cryptica.
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Related In: Results  -  Collection

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Fig2: Cultures of T. weissflogii P09 and C. cryptica CCMP 331 under two-stage nutrient regime. (A) Growth curves during the first (from day 0 to day 6) and second (from day 6 to day 11) stage of growth for Thalassiosira weissflogii . Gray lines indicate nutrient consumption under replete conditions; (B) growth curves during the first (from day 0 to day 8) and second (from day 8 to day 14) stage of growth for C. cryptica. Gray lines indicate nutrient consumption under replete conditions; (C) growth curve and nutrient consumption under depleted conditions (second stage of growth) for Thalassiosira weissflogii P09; (D) growth curve and nutrient consumption under depleted conditions (second stage of growth) for C. cryptica.
Mentions: As shown in Figure 2, the two diatoms consumed both silicon and nitrogen at different extent during the exponential growth phase. In agreement with the literature [30-32], after 2 days, silicon had diminished to close to zero, whereas nitrogen levels had decreased more slowly but were nonetheless reduced to one third of the starting supply by the time cells had entered the stationary phase (6 days for T. weissflogii P09 and 8 days for C. cryptica) (Figure 2A,B). A similar response was also recorded during the second stage of growth when cultures were gently centrifuged and re-suspended in both replete and nutrient-limited media. Since silicon is an essential nutrient for diatoms [33], it was immediately incorporated when added to the medium, independently of the culture conditions of both species (Figure 2C,D). On the other hand, nitrogen was consumed to a small extent in Si-deprived cultures. Interestingly, the two species responded differently to Si limitation, since C. cryptica grew better than T. weissflogii P09 when Si was reduced or absent in the medium.Figure 2

Bottom Line: The effect was less pronounced in cultures where silicon was reduced to 20% of the standard supply.Nitrogen limitation did not affect growth rates but led to lipid remodeling and de novo synthesis of triacylglycerols.Triacylglycerols in T. weissflogii and C. cryptica can account for up to 82% and 88% of total glycerolipids, thereby suggesting that the two species are promising candidates for large-scale experimentation for biofuel production.

View Article: PubMed Central - PubMed

Affiliation: Istituto di Chimica Biomolecolare (ICB) - CNR, Via Campi Flegrei 34, 80078 Pozzuoli, NA Italy.

ABSTRACT

Background: Diatoms are an ecologically relevant group of microalgae that are not commonly considered for bio-oil production even if they are responsible for massive blooms at sea. Seventeen diatom species were screened for their capacity to produce biomass and lipids, in relation to their growth rate. Triglyceride levels were also assessed as a preferential source of biofuels.

Results: Using statistical analysis, two centric diatoms, Thalassiosira weissflogii and Cyclotella cryptica, were selected as good candidates for oil production. Lipid levels significantly increased when the two diatoms were cultivated in a two-stage process under nitrogen limitation. The effect was less pronounced in cultures where silicon was reduced to 20% of the standard supply. Nitrogen limitation did not affect growth rates but led to lipid remodeling and de novo synthesis of triacylglycerols.

Conclusions: Triacylglycerols in T. weissflogii and C. cryptica can account for up to 82% and 88% of total glycerolipids, thereby suggesting that the two species are promising candidates for large-scale experimentation for biofuel production.

No MeSH data available.