A comprehensive analysis of an effective flocculation method for high quality microalgal biomass harvesting.

Labeeuw, L; Commault, AS; Kuzhiumparambil, U; Emmerton, B; Nguyen, LN; Nghiem, LD; Ralph, PJ

A comprehensive analysis of an effective flocculation method for high quality microalgal biomass harvesting.

Labeeuw, L

Commault, AS Kuzhiumparambil, U

Emmerton, B

Nguyen, LN Nghiem, LD Ralph, PJ

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Publisher:: Elsevier BV
Publication Type:: Journal Article
Citation:: The Science of the total environment, 2020, 752, pp. 141708
Issue Date:: 2020-08-15

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Field	Value	Language
dc.contributor.author	Labeeuw, L https://orcid.org/0000-0002-5167-8386
dc.contributor.author	Commault, AS
dc.contributor.author	Kuzhiumparambil, U https://orcid.org/0000-0003-0582-6779
dc.contributor.author	Emmerton, B https://orcid.org/0000-0003-4106-4791
dc.contributor.author	Nguyen, LN
dc.contributor.author	Nghiem, LD
dc.contributor.author	Ralph, PJ
dc.date.accessioned	2020-10-14T06:46:58Z
dc.date.available	2020-08-13
dc.date.available	2020-10-14T06:46:58Z
dc.date.issued	2020-08-15
dc.identifier.citation	The Science of the total environment, 2020, 752, pp. 141708
dc.identifier.issn	0048-9697
dc.identifier.issn	1879-1026
dc.identifier.uri	http://hdl.handle.net/10453/143245
dc.description.abstract	Flocculation is a low-cost harvesting technique for microalgae biomass production, but flocculation efficiency is species dependent. In this study, we investigated the efficacy of two synthetic (polyacrylamide) and one natural (chitosan) flocculants against three algal species: the cyanobacterium Synechocystis sp., the freshwater Chlorella vulgaris, and the marine Phaeodactylum tricornutum at laboratory and pilot scales to evaluate harvesting efficiency, biomass integrity and media recycling. Growth phase affected the harvesting efficiency of the eukaryotic microalgae. The flocculation was optimal at stationary phase with high flocculation efficiency achieved using polyacrylamides at 24-36 mg/g dry weight. The effect of the flocculants on the harvested biomass was investigated. The flocculated Synechocystis sp. showed a higher proportion of compromised cells compared to C. vulgaris and P. tricornutum likely due to differences in cell walls composition. Compromised cells could lead to the release of valuable products into the surrounding growth media during flocculation. The residual culture media was recycled once with no impact on cell growth for all treatments and algal species. The flocculation technique was demonstrated at pilot-scale using 350 L microalgal suspension, showing an efficiency of 82-90% at a polyacrylamide dosage of 6.5-10 mg/L. This efficiency and the biomass quality are comparable to the laboratory-scale results. Overall, results indicate that polyacrylamide flocculants work on a wide range of species without the need for pre-treatment. The information generated in this study can contribute to making the microalgae industry more competitive.
dc.format	Print-Electronic
dc.language	eng
dc.publisher	Elsevier BV
dc.relation.ispartof	The Science of the total environment
dc.relation.isbasedon	10.1016/j.scitotenv.2020.141708
dc.rights	info:eu-repo/semantics/embargoedAccess
dc.subject.classification	Environmental Sciences
dc.title	A comprehensive analysis of an effective flocculation method for high quality microalgal biomass harvesting.
dc.type	Journal Article
utslib.citation.volume	752
utslib.location.activity	Netherlands
utslib.for	0904 Chemical Engineering
utslib.for	0607 Plant Biology
pubs.organisational-group	/University of Technology Sydney/Faculty of Engineering and Information Technology
pubs.organisational-group	/University of Technology Sydney/Strength - CTWW - Centre for Technology in Water and Wastewater Treatment
pubs.organisational-group	/University of Technology Sydney/Faculty of Engineering and Information Technology/School of Civil and Environmental Engineering
pubs.organisational-group	/University of Technology Sydney
pubs.organisational-group	/University of Technology Sydney/Faculty of Science
pubs.organisational-group	/University of Technology Sydney/Strength - C3 - Climate Change Cluster
utslib.copyright.status	open_access	*
utslib.copyright.embargo	2023-01-31T00:00:00+1000Z
dc.date.updated	2020-10-14T06:46:52Z
pubs.publication-status	Published
pubs.volume	752

Abstract:

Flocculation is a low-cost harvesting technique for microalgae biomass production, but flocculation efficiency is species dependent. In this study, we investigated the efficacy of two synthetic (polyacrylamide) and one natural (chitosan) flocculants against three algal species: the cyanobacterium Synechocystis sp., the freshwater Chlorella vulgaris, and the marine Phaeodactylum tricornutum at laboratory and pilot scales to evaluate harvesting efficiency, biomass integrity and media recycling. Growth phase affected the harvesting efficiency of the eukaryotic microalgae. The flocculation was optimal at stationary phase with high flocculation efficiency achieved using polyacrylamides at 24-36 mg/g dry weight. The effect of the flocculants on the harvested biomass was investigated. The flocculated Synechocystis sp. showed a higher proportion of compromised cells compared to C. vulgaris and P. tricornutum likely due to differences in cell walls composition. Compromised cells could lead to the release of valuable products into the surrounding growth media during flocculation. The residual culture media was recycled once with no impact on cell growth for all treatments and algal species. The flocculation technique was demonstrated at pilot-scale using 350 L microalgal suspension, showing an efficiency of 82-90% at a polyacrylamide dosage of 6.5-10 mg/L. This efficiency and the biomass quality are comparable to the laboratory-scale results. Overall, results indicate that polyacrylamide flocculants work on a wide range of species without the need for pre-treatment. The information generated in this study can contribute to making the microalgae industry more competitive.

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http://hdl.handle.net/10453/143245