The diatom Phaeodactylum tricornutum (Pt) has the ability to store up to 45% of dry cell weight as triacylglycerol (TAG), a neutral lipid and precursor to biodiesel1. To take advantage of this innate ability, we need to understand how metabolic pathways adjust to changing environmental conditions. The long-term goal of this project is to promote efficient production of high-value and fuel-related compounds through optimization of metabolic fluxes in Pt. Building upon our expertise in 13C metabolic flux analysis (MFA),2 our current goal is to develop novel experimental protocols and data analysis workflows to enable 13C MFA of Pt. We are currently investigating the metabolic adjustments of Pt to two variables, light and genetic knockout of TAG degradation enzymes, which strongly affect cell growth and lipid accumulation. In this presentation, we discuss the optimization of the isotope labeling experiments and metabolic models for these conditions. In our optimization, we observed phenotypes of the diatom during stationary phase and exponential phase at higher optical densities by looking at growth rate, chlorophyll content and metabolism. We discuss our optimization of the metabolic model and the biomass equation reflect the different experimental conditions. We also investigate the differences in phenotype and in metabolism when we knockout the Acyl-CoA dehydrogenase (ACAD) enzyme during nitrogen repletion after starvation. Our novel MFA analysis will include a new model that uses compartmentalization in conjunction with metabolic data generated from our tailored GC-MS and LC-MS/MS measurements to compare metabolism of different strains of diatoms and under different light conditions.

Modeling carbon metabolism of the diatom Phaeodactylum tricornutum due to genetic knockout of TAG degradation enzymes and to high light versus low light conditions

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.