Biphasic lipid extraction from microalgae after PEF-treatment reduces the energy demand of the downstream process

Abstract Background The gradual extrusion of water-soluble intracellular components (such as proteins) from microalgae after pulsed electric field (PEF) treatment is a well-documented phenomenon. This could be utilized in biorefinery applications with lipid extraction taking place after such an ‘inc...

Full description

Saved in:
Bibliographic Details
Main Authors: Ioannis Papachristou, Natalja Nazarova, Rüdiger Wüstner, Robin Lina, Wolfgang Frey, Aude Silve
Format: Article
Language:English
Published: BMC 2025-01-01
Series:Biotechnology for Biofuels and Bioproducts
Subjects:
Online Access:https://doi.org/10.1186/s13068-025-02608-7
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1832571943799226368
author Ioannis Papachristou
Natalja Nazarova
Rüdiger Wüstner
Robin Lina
Wolfgang Frey
Aude Silve
author_facet Ioannis Papachristou
Natalja Nazarova
Rüdiger Wüstner
Robin Lina
Wolfgang Frey
Aude Silve
author_sort Ioannis Papachristou
collection DOAJ
description Abstract Background The gradual extrusion of water-soluble intracellular components (such as proteins) from microalgae after pulsed electric field (PEF) treatment is a well-documented phenomenon. This could be utilized in biorefinery applications with lipid extraction taking place after such an ‘incubation’ period, i.e., a post-PEF-treatment step during which the biomass is left undisturbed before any further processing. The goal of this work was to further explore how this incubation could improve lipid extraction. Results Experiments were conducted on wet, freshly harvested Auxenochlorella protothecoides, treated with 0.25 or 1.5 MJ/kgDW and incubated for 24 h. Lipid extraction took place with a monophasic ethanol:hexane:water, 1:0.41:0.04 vol/vol/vol mixture with a 75.6 mL solvent per 1 g of dry biomass ratio. The kinetics of the extraction were studied with samples taken between 10 and 1080 min from fresh and incubated biomass. The yields at 10 min were significantly increased with incubation compared to without (31.2% dry weight compared to 1.81%, respectively). The experimental data were fitted with the Patricelli model where extraction occurs in two steps, a rapid washing of immediate available lipids and a slower diffusion one. During Nile-Red staining of microalgae and microscopy imaging, a shift of emission from both GFP and RFP channels to mostly RFP was observed indicating an increase in the polarity of the environment of Nile-Red. These led to an adaption of a biphasic ethanol:hexane:water 1:6:0.4 vol/vol/vol solvent with 37 mL solvent per 1 g of dry biomass ratio which while ineffective on fresh biomass, achieved a 27% dry weight yield from incubated microalgae. The extraction efficiency in the biphasic route was lower compared to the monophasic (i.e., 69% and 95%, respectively). It was compensated however, by the significant solvent reduction (37 mL to 75.6 mL respectively), in particular the ethanol minimization. For the extraction of 1 L lipids, it was estimated that the energy consumption ratio for the biphasic process was 1.6 compared to 9.9 for monophasic, making clearly the most preferential one. Conclusions This biphasic approach significantly reduces solvent consumption and the respective energy requirement for solvent recovery. Incubation thus could majorly improve the commercialization prospects of the process. Graphical abstract
format Article
id doaj-art-9159e4f9612a4fd7a999d103e691103a
institution Kabale University
issn 2731-3654
language English
publishDate 2025-01-01
publisher BMC
record_format Article
series Biotechnology for Biofuels and Bioproducts
spelling doaj-art-9159e4f9612a4fd7a999d103e691103a2025-02-02T12:12:41ZengBMCBiotechnology for Biofuels and Bioproducts2731-36542025-01-0118111410.1186/s13068-025-02608-7Biphasic lipid extraction from microalgae after PEF-treatment reduces the energy demand of the downstream processIoannis Papachristou0Natalja Nazarova1Rüdiger Wüstner2Robin Lina3Wolfgang Frey4Aude Silve5Institute for Pulsed Power and Microwave Technology (IHM), Karlsruhe Institute of Technology (KIT)Institute for Pulsed Power and Microwave Technology (IHM), Karlsruhe Institute of Technology (KIT)Institute for Pulsed Power and Microwave Technology (IHM), Karlsruhe Institute of Technology (KIT)Institute for Pulsed Power and Microwave Technology (IHM), Karlsruhe Institute of Technology (KIT)Institute for Pulsed Power and Microwave Technology (IHM), Karlsruhe Institute of Technology (KIT)Institute for Pulsed Power and Microwave Technology (IHM), Karlsruhe Institute of Technology (KIT)Abstract Background The gradual extrusion of water-soluble intracellular components (such as proteins) from microalgae after pulsed electric field (PEF) treatment is a well-documented phenomenon. This could be utilized in biorefinery applications with lipid extraction taking place after such an ‘incubation’ period, i.e., a post-PEF-treatment step during which the biomass is left undisturbed before any further processing. The goal of this work was to further explore how this incubation could improve lipid extraction. Results Experiments were conducted on wet, freshly harvested Auxenochlorella protothecoides, treated with 0.25 or 1.5 MJ/kgDW and incubated for 24 h. Lipid extraction took place with a monophasic ethanol:hexane:water, 1:0.41:0.04 vol/vol/vol mixture with a 75.6 mL solvent per 1 g of dry biomass ratio. The kinetics of the extraction were studied with samples taken between 10 and 1080 min from fresh and incubated biomass. The yields at 10 min were significantly increased with incubation compared to without (31.2% dry weight compared to 1.81%, respectively). The experimental data were fitted with the Patricelli model where extraction occurs in two steps, a rapid washing of immediate available lipids and a slower diffusion one. During Nile-Red staining of microalgae and microscopy imaging, a shift of emission from both GFP and RFP channels to mostly RFP was observed indicating an increase in the polarity of the environment of Nile-Red. These led to an adaption of a biphasic ethanol:hexane:water 1:6:0.4 vol/vol/vol solvent with 37 mL solvent per 1 g of dry biomass ratio which while ineffective on fresh biomass, achieved a 27% dry weight yield from incubated microalgae. The extraction efficiency in the biphasic route was lower compared to the monophasic (i.e., 69% and 95%, respectively). It was compensated however, by the significant solvent reduction (37 mL to 75.6 mL respectively), in particular the ethanol minimization. For the extraction of 1 L lipids, it was estimated that the energy consumption ratio for the biphasic process was 1.6 compared to 9.9 for monophasic, making clearly the most preferential one. Conclusions This biphasic approach significantly reduces solvent consumption and the respective energy requirement for solvent recovery. Incubation thus could majorly improve the commercialization prospects of the process. Graphical abstracthttps://doi.org/10.1186/s13068-025-02608-7Pulsed electric fieldBiphasic lipid extractionMicroalgae
spellingShingle Ioannis Papachristou
Natalja Nazarova
Rüdiger Wüstner
Robin Lina
Wolfgang Frey
Aude Silve
Biphasic lipid extraction from microalgae after PEF-treatment reduces the energy demand of the downstream process
Biotechnology for Biofuels and Bioproducts
Pulsed electric field
Biphasic lipid extraction
Microalgae
title Biphasic lipid extraction from microalgae after PEF-treatment reduces the energy demand of the downstream process
title_full Biphasic lipid extraction from microalgae after PEF-treatment reduces the energy demand of the downstream process
title_fullStr Biphasic lipid extraction from microalgae after PEF-treatment reduces the energy demand of the downstream process
title_full_unstemmed Biphasic lipid extraction from microalgae after PEF-treatment reduces the energy demand of the downstream process
title_short Biphasic lipid extraction from microalgae after PEF-treatment reduces the energy demand of the downstream process
title_sort biphasic lipid extraction from microalgae after pef treatment reduces the energy demand of the downstream process
topic Pulsed electric field
Biphasic lipid extraction
Microalgae
url https://doi.org/10.1186/s13068-025-02608-7
work_keys_str_mv AT ioannispapachristou biphasiclipidextractionfrommicroalgaeafterpeftreatmentreducestheenergydemandofthedownstreamprocess
AT nataljanazarova biphasiclipidextractionfrommicroalgaeafterpeftreatmentreducestheenergydemandofthedownstreamprocess
AT rudigerwustner biphasiclipidextractionfrommicroalgaeafterpeftreatmentreducestheenergydemandofthedownstreamprocess
AT robinlina biphasiclipidextractionfrommicroalgaeafterpeftreatmentreducestheenergydemandofthedownstreamprocess
AT wolfgangfrey biphasiclipidextractionfrommicroalgaeafterpeftreatmentreducestheenergydemandofthedownstreamprocess
AT audesilve biphasiclipidextractionfrommicroalgaeafterpeftreatmentreducestheenergydemandofthedownstreamprocess