Beta-lactamase reporter system for selecting high-producing yeast clones

Area of Science:

• Biotechnology
• Molecular Biology
• Bioprocess Engineering

Background:

• Efficient screening of high-producing clones is crucial for cost-effective biopharmaceutical production.
• Current methods for clone selection can be time-consuming and expensive.
• The yeast Pichia pastoris is a widely used host for recombinant protein expression.

Purpose of the Study:

• To develop a rapid, simple, and inexpensive method for selecting high-producing clones in Pichia pastoris.
• To utilize a beta-lactamase reporter system to correlate reporter activity with the expression level of a gene of interest.
• To demonstrate the applicability of this system for selecting clones expressing pharmaceutically relevant proteins.

Main Methods:

• Constructed a novel expression vector with two independent expression cassettes in Pichia pastoris.
• Integrated the gene of interest (GFP as a model) and the beta-lactamase reporter gene into the same genome locus.
• Utilized beta-lactamase activity, detected by substrate hydrolysis and color change, to select high-producing clones.

Main Results:

• High-producing green fluorescent protein (GFP) clones were directly selected on plates.
• Beta-lactamase activity showed a positive correlation with GFP fluorescence intensity.
• The developed reporter system is effective for rapid screening of high-expression clones.

Conclusions:

• The beta-lactamase reporter system provides an efficient and cost-effective method for screening high-producing clones in Pichia pastoris.
• This system is widely applicable to various proteins and other yeast expression systems like Saccharomyces cerevisiae and Hansenula polymorpha.
• This approach can significantly impact biopharmaceutical production by lowering costs and improving efficiency.