Growth, Turnover, and Recycling of Cyanobacteria from Soda Lakes

Paquette, Alexandre

Growth, Turnover, and Recycling of Cyanobacteria from Soda Lakes

dc.contributor.advisor	Strous, Marc
dc.contributor.advisor	De la Hoz Siegler, Hector
dc.contributor.author	Paquette, Alexandre
dc.contributor.committeemember	Hubert, Casey
dc.contributor.committeemember	Lauer, Rachel
dc.date	2025-06-09
dc.date.accessioned	2025-02-12T22:59:25Z
dc.date.available	2025-02-12T22:59:25Z
dc.date.issued	2025-01-22
dc.description.abstract	Cyanobacteria have been proposed as a promising resource for the next generation of industrial biotechnologies to produce high-value food ingredients and bioactive compounds. As photosynthetic microorganisms, they require only sunlight, carbon dioxide, water, and essential nutrients to thrive. Cyanobacteria are remarkable for growing in non-arable land, avoiding competition with conventional crops. They can also be cultivated in seawater and wastewater, conserving precious freshwater resources and making them ideal for industrial applications in water-scarce regions. Their versatility and potential for large-scale, sustainable bioproduction make cyanobacteria key players in developing eco-friendly biotechnologies to address global challenges in food and chemicals. However, the scale-up of these biotechnologies faces significant challenges. One major challenge is cultivation, which includes carbon supply, high water requirements, and nutrient availability. This thesis explores strategies to address these challenges by investigating the reuse and recycling of waste products in a closed-loop cultivation system. The study focuses on cultivating a cyanobacterial consortium under high pH and alkalinity conditions, beginning with examining nutrient management and the reuse of spent medium (Chapter 2). The results show that the spent medium contains many essential nutrients for cultivation, but requires replenishment with nitrogen and bicarbonate before it can be reused effectively. Additionally, the spent medium can be reused for several cycles without negatively impacting biomass growth, provided such replenishment is implemented. This approach of reusing spent media reduces water and nutrient demands over multiple cycles, offering a sustainable cultivation method. Chapter 3 delves into the microbial ecology and biogeochemistry of sediments in Canadian soda lakes, the natural habitat of the cyanobacterial consortium. This chapter highlights unique microbial adaptations to extreme environments and provides insights into nutrient cycling and ecological resilience. Chapter 4 analyzes waste products from anaerobic digestion, revealing their potential as nutrient sources while also uncovering contaminants such as 2,4-di-tert-butylphenol, which may contribute to culture crashes. These findings underscore the need for pretreatment strategies to recycle anaerobic digestion waste in the closed-loop system.
dc.identifier.citation	Paquette, A. (2025). Growth, turnover, and recycling of cyanobacteria from soda lakes (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.
dc.identifier.uri	https://hdl.handle.net/1880/120574
dc.language.iso	en
dc.publisher.faculty	Science
dc.publisher.institution	University of Calgary
dc.rights	University of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.
dc.subject	microalgal culitvation
dc.subject	nutrient recycling
dc.subject	bioengineering
dc.subject	renewable energy
dc.subject.classification	Microbiology
dc.subject.classification	Biogeochemistry
dc.title	Growth, Turnover, and Recycling of Cyanobacteria from Soda Lakes
dc.type	doctoral thesis
thesis.degree.discipline	Geoscience
thesis.degree.grantor	University of Calgary
thesis.degree.name	Doctor of Philosophy (PhD)
ucalgary.thesis.accesssetbystudent	I do not require a thesis withhold – my thesis will have open access and can be viewed and downloaded publicly as soon as possible.