Engineering triacylglycerol production from sugars in oleaginous yeasts

Area of Science:

• Biotechnology
• Microbiology
• Metabolic Engineering

Background:

• Oleaginous yeasts naturally synthesize high levels of triacylglycerol (TAG) lipids.
• While many TAG production steps are known, critical pathway components remain uncharacterized.
• This knowledge gap hinders metabolic engineering efforts and limits the theoretical maximum lipid yield.

Purpose of the Study:

• To present the current understanding of TAG biosynthesis in oleaginous yeasts.
• To review existing metabolic engineering strategies for enhancing lipid production.
• To discuss bioprocess limitations affecting lipid accumulation.

Main Methods:

• Review of current literature on oleaginous yeast TAG biosynthesis.
• Analysis of metabolic engineering approaches applied to lipid production.
• Development of a simplified substrate allocation model.

Main Results:

• The study outlines the knowns and unknowns in the TAG biosynthesis pathway.
• It discusses how bioprocess parameters influence lipid production.
• A substrate allocation model is presented to link lipid content to yield, productivity, and cost.

Conclusions:

• Understanding the complete TAG pathway is crucial for effective metabolic engineering.
• Bioprocess constraints significantly impact the feasibility of microbial lipid production.
• The developed model provides a framework for evaluating and optimizing lipid production metrics.