Combinatorial Screening for Transgenic Yeasts with High Cellulase Activities in Combination with a Tunable Expression...

Area of Science:

• Metabolic Engineering
• Synthetic Biology
• Biotechnology

Background:

• Optimizing simultaneous expression of multiple enzymes is crucial for metabolic engineering.
• A tunable protein expression system using genome-integrated genes was previously developed.
• This system utilizes a library of expression cassettes with varying gene-expression control elements.

Purpose of the Study:

• To apply a tunable protein expression system for simultaneous cellulase expression in yeast.
• To optimize the expression of three key cellulases: cellobiohydrolase 1, cellobiohydrolase 2, and endoglucanase 2.
• To evaluate the effectiveness of combinatorial screening with diverse gene expression cassettes.

Main Methods:

• Utilized four gene expression cassettes with graded protein expression levels.
• Applied these cassettes to the simultaneous expression of three cellulases in yeast.
• Conducted combinatorial screening to identify optimal transgenic yeast strains.

Main Results:

• Obtained transgenic yeast strains exhibiting higher cellulase expression levels.
• Achieved superior enzyme expression compared to strains with single high-performance cassettes.
• Demonstrated the efficacy of the tunable expression system and screening approach.

Conclusions:

• The developed method is a powerful tool for optimizing simultaneous multi-enzyme expression.
• This approach has broad applicability in metabolic engineering and synthetic biology.
• The tunable system and combinatorial screening enhance enzyme production in engineered organisms.