Biosynthesis of the Resistant Polymer in the Alga Botryococcus braunii. Studies on the Possible Direct Precursors

Laureillard, J.; Largeau, Claude; Waeghemaeker, F.

doi:10.1021/np50047a005

Cited by 22 publications

(5 citation statements)

References 5 publications

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“…These TAG may be difficult to extract due to their large molecular weight, though further analysis of intact TAG would be required to confirm this. Alternatively, B. braunii is known to produce degradation-resistant biopolymers that include the identified C28:1/C28:2 fatty acids [26], which may also explain this phenomenon.…”

Section: Discussionmentioning

confidence: 99%

Suitability of Soxhlet Extraction to Quantify Microalgal Fatty Acids as Determined by Comparison with In Situ Transesterification

McNichol

MacDougall

Melanson

et al. 2011

Lipids

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To assess Soxhlet extraction as a method for quantifying fatty acids (FA) of microalgae, crude lipid, FA content from Soxhlet extracts and FA content from in situ transesterification (ISTE) were compared. In most cases, gravimetric lipid content was considerably greater (up to sevenfold) than the FA content of the crude lipid extract. FA content from Soxhlet lipid extraction and ISTE were similar in 12/18 samples, whereas in 6/18 samples, total FA content from Soxhlet extraction was less than the ISTE procedure. Re-extraction of residual biomass from Soxhlet extraction with ISTE liberated a quantity of FA equivalent to this discrepancy. Employing acid hydrolysis before Soxhlet extraction yielded FA content roughly equivalent to ISTE, indicating that acidic conditions of ISTE are responsible for this observed greater recovery of FA. While crude lipid derived from Soxhlet extraction was not a useful proxy for FA content for the species tested, it is effective in most strains at extracting total saponifiable lipid. Lipid class analysis showed the source of FA was primarily polar lipids in most samples (12/18 lipid extracts contained \5% TAG), even in cases where total FA content was high ([15%). This investigation confirms the usefulness of ISTE, reveals limitations of gravimetric methods for projecting biodiesel potential of microalgae, and reinforces the need for intelligent screening using both FA and lipid class analysis.

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Section: Discussionmentioning

confidence: 99%

Suitability of Soxhlet Extraction to Quantify Microalgal Fatty Acids as Determined by Comparison with In Situ Transesterification

McNichol

MacDougall

Melanson

et al. 2011

Lipids

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“…COSY experiments established that in (73)- (75) the methine protons of the ether function resonated at 03.23 for H(10) and 3.43 for H(9'); the signal of proton H(lO'), on the hydroxyl-bearing carbon, appeared at 03.49 and the signal of proton H(9), attached to the ester-bearing carbon, was at 05.02. In structure (72), the protons were assigned on the basis of spectral comparisons with the diacetate derivative: protons H(9) and H(lO') on hydroxyl bearing carbons resonated at 03.57, whereas those attached to the carbons of the ether function, H (10) and H(9') were found at 03.32. The 13C-NMR spectra of (73)- (75) (72)- (74) and their TMS derivatives exhibited similar fragmentation modes giving ions of substantial diagnostic value, as shown in Fig.…”

Section: R -Ch -Ch-r /mentioning

confidence: 99%

“…Coupling might start by protonation of an epoxide (64), (65) or (66) followed by the specific cleavage of the C(9')-O bond; the carbocation formed would then attack a second epoxide (64) with concomitant cleavage of the C(9)-O bond. Then the positive charge at C(9) would be neutralized by reaction with water or a fatty acid, leading to (72) or (73)- (75), respectively.…”

Section: R -Ch -Ch-r /mentioning

confidence: 99%

“…In addition, feeding experiments with radiolabelled compounds confirmed the involvement of long unbranched, hydrocarbon chains in the biopolymer network. Indeed, sodium DL [2_ 14 C] mevalonate, a botryococcene precursor, was poorly incorporated, while [10_ 14 C] oleic acid resulted in strongly labelled PRB B (69,72); in this latter case radioactivity was recovered both in the hydrocarbons and the fatty acids released on pyrolysis. To date the origin of PRB B is still obscure, no ether lipids similar to those found in the A race have been so far isolated from the Brace.…”

Section: Resistant Biopolymers From Outer Walls (P Rb)mentioning

confidence: 99%

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Lipids and Macromolecular Lipids of the Hydrocarbon-rich Microalga Botryococcus braunii. Chemical Structure and Biosynthesis. Geochemical and Biotechnological Importance

Metzger

Largeau

Casadevall

1991

Fortschritte Der Chemie Organischer Naturstoffe / Progress in the Chemistry of Organic Natural Products

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“…To test this hypothesis, we examined the effect of hydrophobic intracellular substances on hydrocarbon recovery efficiency from concentrated samples. Oleic acid, which is one of the main fatty acids in B. braunii race B , and a precursor of the biopolymer used to synthesize the colony matrix, , was used as a model hydrophobic intracellular compound. The concentrated sample filtered under the same conditions was used (dry cell weight ∼3 g/L).…”

Section: Resultsmentioning

confidence: 99%

Effect of Mechanical Pretreatment on Hydrocarbon Extraction from Concentrated Wet Hydrocarbon-Rich Microalga, Botryococcus braunii

et al. 2018

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In the present study, we investigated the effects of concentrating a cell suspension of a hydrocarbon-rich microalga, Botryococcus braunii, by membrane filtration on hydrocarbon recovery efficiency. B. braunii suspensions before and after filtration were mechanically pretreated with a high-pressure homogenizer or a JET PASTER high-speed mixer. Concentrating the suspension increased the apparent viscosity of the sample and altered the particle size and shape distributions. The increase of viscosity was derived from the existence probability that was caused by shear forces in the pump that introduced the suspension into the membrane filter and/or between the membrane wall and algae. Homogenizer treatment decreased the sample viscosity from 20 to 5 mPa·s due to the collapse of the bridge between the algae and polysaccharides. The treatment also decreased the hydrocarbon recovery efficiency from 60% to 15% because of the release of intracellular substances that prevented hydrocarbon extraction. In contrast, JET PASTER treatment increased the hydrocarbon recovery efficiency by removing polysaccharides surrounding the colonies and disrupting colonies, without disrupting the cells. Adding oleic acid as a model intracellular substance to the concentrated sample before extraction decreased the amount of extracted hydrocarbon. These results demonstrate that concentrating the sample by filtration combined with JET PASTER treatment can improve the hydrocarbon recovery efficiency of B. braunii. In addition, an energy analysis was performed in the present study. The energy consumption of the JET PASTER treatment combined with filtration was 7.6 times as high as the energy produced.

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Biosynthesis of the Resistant Polymer in the Alga Botryococcus braunii. Studies on the Possible Direct Precursors

Cited by 22 publications

References 5 publications

Suitability of Soxhlet Extraction to Quantify Microalgal Fatty Acids as Determined by Comparison with In Situ Transesterification

Suitability of Soxhlet Extraction to Quantify Microalgal Fatty Acids as Determined by Comparison with In Situ Transesterification

Lipids and Macromolecular Lipids of the Hydrocarbon-rich Microalga Botryococcus braunii. Chemical Structure and Biosynthesis. Geochemical and Biotechnological Importance

Effect of Mechanical Pretreatment on Hydrocarbon Extraction from Concentrated Wet Hydrocarbon-Rich Microalga, Botryococcus braunii

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