Lycopene overproduction in Saccharomyces cerevisiae through combining pathway engineering with host engineering

Area of Science:

• Biotechnology
• Synthetic Biology
• Metabolic Engineering

Background:

• Microbial production of lycopene is gaining importance for commercial and medical applications.
• Saccharomyces cerevisiae offers a safer alternative to Escherichia coli for lycopene synthesis.
• Current lycopene yields in S. cerevisiae are suboptimal, necessitating host and pathway optimization.

Purpose of the Study:

• To engineer Saccharomyces cerevisiae for high-level lycopene overproduction.
• To overcome limitations in lycopene yield and downstream processing in yeast hosts.
• To establish a robust platform for microbial production of lycopene.

Main Methods:

• Constructed the lycopene biosynthesis pathway using CrtE, CrtB, and CrtI genes.
• Engineered the host cell by deleting specific genetic loci (YPL062W, YJL064W, ROX1, DOS2) and up-regulating INO2.
• Optimized the heterologous pathway by screening diverse enzyme sources (e.g., BtCrtI) and fine-tuning gene expression.
• Evaluated the impact of cell mating types on lycopene production.

Main Results:

• Deletion of YPL062W increased cytosolic acetyl-CoA pool by 100%.
• Identified an optimal enzyme combination, with Blakeslea trispora CrtI showing superior performance.
• Achieved a 22-fold increase in lycopene yield, reaching 54.63 mg/g DCW.
• Attained a final lycopene production of 55.56 mg/g DCW in fed-batch fermentation.

Conclusions:

• Successfully engineered Saccharomyces cerevisiae for significantly enhanced lycopene production.
• Combinatorial engineering of host cell and heterologous pathway led to a 22-fold yield improvement.
• The achieved yield of 55.56 mg/g DCW represents the highest reported in yeast.
• This study provides a valuable framework for microbial overproduction of pharmaceutical and chemical products.