Hydrothermal Extraction of Microalgae Fatty Acid Influences Hydrochar Phytotoxicity

Christopher Ennis, Joyce Clarke, Katherine Neate, Joana Cerejeira, Lewis Tull

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Abstract

Hydrothermal carbonization (HTC) of microalgae biomass for the production of triacylglycerides is a potentially valuable enabling technology for a waste water treatment-based integrated biorefinery. Here, HTC was used to treat Phaeodactylum tricornutum lipid-rich biomass producing a solid hydrochar from the surface of which adsorbed lipids were removed by hexane extraction following filtration of the solid hydrochar from the process liquid product. Approximately 7% of the input biomass was recovered and transesterified for qualitative and quantitative GCMS analysis for fatty acid methyl esters. Transesterifiable lipids accounted for 94% of the material recovered by solvent extraction. Of the transesterified fatty acids (FA) analysed, the majority was monounsaturated (40.4%) and saturated (37%) C-16 FA. Other FA detected included saturated and monounsaturated C-18 (7.7% and 1.9%) and saturated C-14 (5.3%) and C-25 (1.5%). Thermal analysis (TGA/DSC) of the hydrochar in air showed calorific values of 10.6 MJ kg-1 (delipidated hydrochar) and 3.1 MJ kg-1 (non-delipidated hydrochar) with the latter exhibiting the presence of volatalisable components. Germination trials were conducted to assess the potential phytotoxic effects of these hydrochars. Delipidated hydrochar showed a germination index of 73% suggesting the presence of some phytotoxicity. Non-delipidated hydrochar showed high germination index results of 102% (unground) and 126 % (ground). Taken together with the observation of reduced root hair proliferation in these two test conditions, this suggests the operation of a second phytotoxic effect that is removed by delipidation.
Original languageEnglish
Pages (from-to)-
JournalFrontiers in Environmental Science
DOIs
Publication statusPublished - 14 Aug 2017

Fingerprint

phytotoxicity
microalgae
germination
fatty acids
lipids
biorefining
Phaeodactylum tricornutum
thermal analysis
biomass
root hairs
wastewater treatment
hexane
quantitative analysis
biomass production
air
liquids
testing
hydrothermal carbonization

Bibliographical note

Author can archive post-print (ie final draft post-refereeing). [This Document is Protected by copyright and was first published by Frontiers. All rights reserved. it is reproduced with permission.] http://www.sherpa.ac.uk/romeo/issn/2296-665X/

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Ennis, Christopher ; Clarke, Joyce ; Neate, Katherine ; Cerejeira, Joana ; Tull, Lewis. / Hydrothermal Extraction of Microalgae Fatty Acid Influences Hydrochar Phytotoxicity. In: Frontiers in Environmental Science. 2017 ; pp. -.
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abstract = "Hydrothermal carbonization (HTC) of microalgae biomass for the production of triacylglycerides is a potentially valuable enabling technology for a waste water treatment-based integrated biorefinery. Here, HTC was used to treat Phaeodactylum tricornutum lipid-rich biomass producing a solid hydrochar from the surface of which adsorbed lipids were removed by hexane extraction following filtration of the solid hydrochar from the process liquid product. Approximately 7{\%} of the input biomass was recovered and transesterified for qualitative and quantitative GCMS analysis for fatty acid methyl esters. Transesterifiable lipids accounted for 94{\%} of the material recovered by solvent extraction. Of the transesterified fatty acids (FA) analysed, the majority was monounsaturated (40.4{\%}) and saturated (37{\%}) C-16 FA. Other FA detected included saturated and monounsaturated C-18 (7.7{\%} and 1.9{\%}) and saturated C-14 (5.3{\%}) and C-25 (1.5{\%}). Thermal analysis (TGA/DSC) of the hydrochar in air showed calorific values of 10.6 MJ kg-1 (delipidated hydrochar) and 3.1 MJ kg-1 (non-delipidated hydrochar) with the latter exhibiting the presence of volatalisable components. Germination trials were conducted to assess the potential phytotoxic effects of these hydrochars. Delipidated hydrochar showed a germination index of 73{\%} suggesting the presence of some phytotoxicity. Non-delipidated hydrochar showed high germination index results of 102{\%} (unground) and 126 {\%} (ground). Taken together with the observation of reduced root hair proliferation in these two test conditions, this suggests the operation of a second phytotoxic effect that is removed by delipidation.",
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Hydrothermal Extraction of Microalgae Fatty Acid Influences Hydrochar Phytotoxicity. / Ennis, Christopher; Clarke, Joyce; Neate, Katherine; Cerejeira, Joana; Tull, Lewis.

In: Frontiers in Environmental Science, 14.08.2017, p. -.

Research output: Contribution to journalArticleResearchpeer-review

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AU - Cerejeira, Joana

AU - Tull, Lewis

N1 - Author can archive post-print (ie final draft post-refereeing). [This Document is Protected by copyright and was first published by Frontiers. All rights reserved. it is reproduced with permission.] http://www.sherpa.ac.uk/romeo/issn/2296-665X/

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N2 - Hydrothermal carbonization (HTC) of microalgae biomass for the production of triacylglycerides is a potentially valuable enabling technology for a waste water treatment-based integrated biorefinery. Here, HTC was used to treat Phaeodactylum tricornutum lipid-rich biomass producing a solid hydrochar from the surface of which adsorbed lipids were removed by hexane extraction following filtration of the solid hydrochar from the process liquid product. Approximately 7% of the input biomass was recovered and transesterified for qualitative and quantitative GCMS analysis for fatty acid methyl esters. Transesterifiable lipids accounted for 94% of the material recovered by solvent extraction. Of the transesterified fatty acids (FA) analysed, the majority was monounsaturated (40.4%) and saturated (37%) C-16 FA. Other FA detected included saturated and monounsaturated C-18 (7.7% and 1.9%) and saturated C-14 (5.3%) and C-25 (1.5%). Thermal analysis (TGA/DSC) of the hydrochar in air showed calorific values of 10.6 MJ kg-1 (delipidated hydrochar) and 3.1 MJ kg-1 (non-delipidated hydrochar) with the latter exhibiting the presence of volatalisable components. Germination trials were conducted to assess the potential phytotoxic effects of these hydrochars. Delipidated hydrochar showed a germination index of 73% suggesting the presence of some phytotoxicity. Non-delipidated hydrochar showed high germination index results of 102% (unground) and 126 % (ground). Taken together with the observation of reduced root hair proliferation in these two test conditions, this suggests the operation of a second phytotoxic effect that is removed by delipidation.

AB - Hydrothermal carbonization (HTC) of microalgae biomass for the production of triacylglycerides is a potentially valuable enabling technology for a waste water treatment-based integrated biorefinery. Here, HTC was used to treat Phaeodactylum tricornutum lipid-rich biomass producing a solid hydrochar from the surface of which adsorbed lipids were removed by hexane extraction following filtration of the solid hydrochar from the process liquid product. Approximately 7% of the input biomass was recovered and transesterified for qualitative and quantitative GCMS analysis for fatty acid methyl esters. Transesterifiable lipids accounted for 94% of the material recovered by solvent extraction. Of the transesterified fatty acids (FA) analysed, the majority was monounsaturated (40.4%) and saturated (37%) C-16 FA. Other FA detected included saturated and monounsaturated C-18 (7.7% and 1.9%) and saturated C-14 (5.3%) and C-25 (1.5%). Thermal analysis (TGA/DSC) of the hydrochar in air showed calorific values of 10.6 MJ kg-1 (delipidated hydrochar) and 3.1 MJ kg-1 (non-delipidated hydrochar) with the latter exhibiting the presence of volatalisable components. Germination trials were conducted to assess the potential phytotoxic effects of these hydrochars. Delipidated hydrochar showed a germination index of 73% suggesting the presence of some phytotoxicity. Non-delipidated hydrochar showed high germination index results of 102% (unground) and 126 % (ground). Taken together with the observation of reduced root hair proliferation in these two test conditions, this suggests the operation of a second phytotoxic effect that is removed by delipidation.

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