Abstract:
Microalgae, such as Chlamydomonas reinhardtii, offer a sustainable alternative to traditional fermentative microbes for the production of bio-chemicals. Unlike other processes, photosynthetic algae can directly convert inorganic carbon dioxide (CO₂) into bioproducts from its biomass and co-products using light energy. Isoprene, a volatile five-carbon hydrocarbon, is produced by many organisms as a metabolic biproduct and antioxidant. Isoprene has industrial applications as a bulk commodity hydrocarbon, including the production of synthetic rubber and fuels. However, current industrial isoprene production is reliant on petroleum. This dissertation explores the biotechnological potential of C. reinhardtii as a platform for isoprene production through metabolic engineering. Genetic modifications were implemented to explore the production of isoprene from the alga’s terpenoid biosynthesis pathway. Although not naturally producing meaningful isoprene titers, metabolic engineering led to significant yields of this co-product without effecting growth. Scalability and carbon sources were addressed by combining photobioreactor systems with online headspace analysis infrastructure. Wastewater was also investigated as a nutrient source to couple waste remediation with isoprene production, however, further experimentation is required to optimize this. The findings of this dissertation demonstrate the capacity of C. reinhardtii to be engineered into a platform for sustainable isoprene production. The integration of metabolic engineering, co-cultivation systems, and environmental sustainability strategies provides a foundation for future research and development in algal-based biofactories for industrial chemicals.

Bio:
Razan Yahya is a PhD candidate at King Abdullah University of Science and Technology (KAUST), conducting research under the supervision of Professor Kyle Lauersen. She completed her undergraduate studies in Genomics and Biotechnology at King Abdulaziz University and earned her Master’s degree in Bioscience at KAUST under the supervision of Professor Carlos Duarte. Her PhD research focuses on advancing sustainable production methods for industrially valuable biochemicals using microalgae, specifically Chlamydomonas reinhardtii, to produce isoprene as a renewable alternative to petrochemical sources.