Microalgae cultivation and harvesting using carbon and sulphate for lipid, protein, and biofuel production

Aditya, Lisa

Microalgae cultivation and harvesting using carbon and sulphate for lipid, protein, and biofuel production

Aditya, Lisa

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Publication Type:: Thesis
Issue Date:: 2025

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Field	Value	Language
dc.contributor.author	Aditya, Lisa
dc.date.accessioned	2026-03-18T03:37:54Z
dc.date.available	2026-03-18T03:37:54Z
dc.date.issued	2025
dc.identifier.uri	http://hdl.handle.net/10453/194367
dc.description	University of Technology Sydney. Faculty of Engineering and Information Technology.	en_US.UTF-8
dc.description.abstract	Microalgae have emerged as a promising platform for carbon capture for producing renewable chemical feedstocks and biofuels. The economic feasibility of microalgae-based systems depends on high costs of cultivation, harvesting, and water reuse. This thesis explores strategies to optimise microalgae growth and harvesting efficiency. Results indicate that balancing CO₂ input (850 mg/L) and light intensity (1089 μmol/m²/s) enhances microalgae growth and carbon fixation, reaching 4.2 g/L. This study highlights key differences in sulphate assimilation and the impact of pH on two freshwater microalgae species for carbon capture from sulphur-rich acidic gas. Scenedesmus sp. utilises NADPH as an electron donor, whereas C. vulgaris relies on ferredoxin. pH fluctuations impaired enzymatic functions, thereby affecting microalgal growth. Optimising nutrient availability and carbon supply controls biomass composition and biofuel potential. Harvesting efficiency was improved using ceramic microfiltration membranes to preconcentrate microalgae solutions before polymer-based harvesting. These membranes demonstrated species-specific performance, minimal fouling (mitigated through aeration), and effective permeate water reuse, facilitating sustainable cultivation cycles. A novel cationic PAPTAC was synthesised for microalgae harvesting. PAPTAC achieved 90–99% flocculation efficiency, outperforming commercial polymers. This thesis advances microalgae systems for greenhouse gas mitigation by optimising cultivation, harvesting, and water reuse, contributing to cost-effective, sustainable applications.	en_US.UTF-8
dc.format	Thesis (PhD)
dc.language.iso	en_US	en_US.UTF-8
dc.relation	https://opus.lib.uts.edu.au/bitstream/10453/194367/1/thesis.pdf
dc.rights	info:eu-repo/semantics/openAccess
dc.rights	The author owns the copyright in this thesis including all reproduction and reuse rights for the work. The work may not be altered without the permission of the copyright owner. Attribution is essential when quoting or paraphrasing from this thesis.
dc.rights	© 2025 Lisa Aditya
dc.rights	au.edu.uts.lib/cph
dc.title	Microalgae cultivation and harvesting using carbon and sulphate for lipid, protein, and biofuel production	en_US.UTF-8
dc.type	Thesis
utslib.copyright.status	open_access	*

Abstract:

Microalgae have emerged as a promising platform for carbon capture for producing renewable chemical feedstocks and biofuels. The economic feasibility of microalgae-based systems depends on high costs of cultivation, harvesting, and water reuse. This thesis explores strategies to optimise microalgae growth and harvesting efficiency. Results indicate that balancing CO₂ input (850 mg/L) and light intensity (1089 μmol/m²/s) enhances microalgae growth and carbon fixation, reaching 4.2 g/L. This study highlights key differences in sulphate assimilation and the impact of pH on two freshwater microalgae species for carbon capture from sulphur-rich acidic gas. Scenedesmus sp. utilises NADPH as an electron donor, whereas C. vulgaris relies on ferredoxin. pH fluctuations impaired enzymatic functions, thereby affecting microalgal growth. Optimising nutrient availability and carbon supply controls biomass composition and biofuel potential. Harvesting efficiency was improved using ceramic microfiltration membranes to preconcentrate microalgae solutions before polymer-based harvesting. These membranes demonstrated species-specific performance, minimal fouling (mitigated through aeration), and effective permeate water reuse, facilitating sustainable cultivation cycles. A novel cationic PAPTAC was synthesised for microalgae harvesting. PAPTAC achieved 90–99% flocculation efficiency, outperforming commercial polymers. This thesis advances microalgae systems for greenhouse gas mitigation by optimising cultivation, harvesting, and water reuse, contributing to cost-effective, sustainable applications.

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http://hdl.handle.net/10453/194367