Repurposing the Diatom Periplastidial Compartment for Heterologous Terpenoid Production

Area of Science:

• Synthetic Biology
• Metabolic Engineering
• Photosynthetic Eukaryotes

Background:

• Diatoms offer sustainable routes for photosynthetic terpenoid production from CO2.
• Compartmentalized engineering potential in diatoms for terpenoid biosynthesis is largely unexplored.

Purpose of the Study:

• To systematically profile the biosynthetic capacity of Phaeodactylum tricornutum.
• To investigate the accessibility of prenyl phosphate precursors in different cellular compartments.
• To establish a foundation for compartmentalized terpenoid biosynthesis engineering in diatoms.

Main Methods:

• Targeted representative terpenoid synthases to the cytosol, chloroplast, and periplastidial compartment (PPC).
• Systematic profiling of prenyl phosphate precursor (DMAPP, GPP, FPP, GGPP) availability.
• Analysis of precursor accessibility and metabolic flux in engineered P. tricornutum.

Main Results:

• All major prenyl phosphate precursors are accessible in the cytosol, chloroplast, and PPC.
• Heterologous terpenoid flux can be sustained in all compartments without significant physiological penalties.
• Production efficiency varies across compartments and terpenoid product classes.

Conclusions:

• The diatom PPC is an engineerable intracellular space integrated with the chloroplast.
• This provides a framework for compartment-specific terpenoid engineering and modular pathway assembly.
• The study highlights opportunities for synthetic biology in photosynthetic eukaryotes and metabolic exchange studies.