Metabolic Engineering of Phaeodactylum tricornutum for Triacylglycerol Production

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dc.contributor.advisorYoung, Jamey
dc.contributor.committeeChairYoung, Jamey
dc.creatorZheng, Amy Olivia
dc.creator.orcid0000-0002-0254-5253
dc.date.accessioned2025-06-06T09:46:14Z
dc.date.available2025-06-06T09:46:14Z
dc.date.created2025-05
dc.date.issued2025-03-18
dc.date.submittedMay 2025
dc.description.abstractCulturing microalgae for biodiesel production is one of the few viable methods to completely replace our reliance on petroleum for transportation vehicles. Phaeodactylum tricornutum (Pt) produces lipids called triacylglycerol (TAG) that can be easily converted into biodiesel. Despite the recent advancements in TAG production, a clear understanding of how environmental conditions and genomic engineering enhance TAG production. In this work, 13C isotopic nonstationary metabolic flux analysis (INST-MFA) was utilized to investigate how light intensity and malic enzyme overexpression increase TAG production. First, wild type Pt cells were cultured under two different light conditions, 60 μE and 250 μE. Increased light intensity was found to increase growth and TAG production. As light intensity increases, the excess fixed carbon was directed towards TAG synthesis instead of biomass. Next, a malic enzyme (ME) overexpressing strain was developed through electroporation. The mutation increased TAG production while maintaining equivalent growth rate to wild type. Using INST-MFA, the primary mechanism of ME was shown to direct the citrate and pyruvate pool towards TAG synthesis and decrease TCA cycle flux. Finally, a systematic analysis of the effect of pool size measurements on flux estimates was conducted. Pool size measurements increase sensitivity to errors in the model. Therefore, inclusion of pool size measurements results in the accurate flux estimates even when there are certain model errors. Overall, these studies show the utility of INST-MFA to elucidate the underlying mechanisms for TAG synthesis. Furthermore, this work highlights the potential of INST-MFA to develop gene targets and optimize cell culture conditions to increase TAG production.
dc.format.mimetypeapplication/pdf
dc.identifier.urihttps://hdl.handle.net/1803/19751
dc.language.isoen
dc.subjectMetabolic Engineering, Biofuels, Metabolic Flux Analysis
dc.titleMetabolic Engineering of Phaeodactylum tricornutum for Triacylglycerol Production
dc.typeThesis
dc.type.materialtext
thesis.degree.disciplineChemical Engineering
thesis.degree.grantorVanderbilt University Graduate School
thesis.degree.levelDoctoral
thesis.degree.namePhD
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