Reprogramming Yeast Metabolism from Alcoholic Fermentation to Lipogenesis.

Area of Science:

• Biotechnology
• Metabolic Engineering
• Synthetic Biology

Background:

• Microbial metabolism is tightly regulated for optimal growth, posing challenges for engineering high-value product synthesis.
• Traditional yeast metabolism favors ethanol fermentation, limiting production of other compounds like lipids.

Purpose of the Study:

• To re-program Saccharomyces cerevisiae metabolism for high-level production of free fatty acids.
• To demonstrate the feasibility of replacing ethanol fermentation with lipogenesis in yeast.

Main Methods:

• Metabolic engineering strategies including altered subcellular trafficking and fine-tuned cofactor supply.
• Deletion of pyruvate decarboxylase enzymes and adaptive laboratory evolution.
• Process design to decrease carbon flux to biomass.

Main Results:

• Achieved production of 33.4 g/L extracellular free fatty acids.
• Successfully replaced ethanol fermentation with a pure lipogenesis metabolism.
• Identified essential pyruvate kinase mutations in evolved strains enabling the lipogenesis phenotype.

Conclusions:

• Metabolic engineering can successfully redirect yeast carbon flux towards lipogenesis.
• Adaptive laboratory evolution is a key tool for overcoming metabolic regulation barriers.
• This work establishes a platform for yeast-based free fatty acid production.