Identifying Amino Acid Overproducers Using Rare-Codon-Rich Markers.

Area of Science:

• Biotechnology
• Molecular Biology
• Synthetic Biology

Background:

• The increasing demand for amino acids necessitates high-performance production strains.
• Conventional methods for identifying amino acid overproducers rely on analog-based screening, which suffers from low accuracy and limited analog availability.
• A more efficient and accurate screening strategy is required to meet market demands.

Purpose of the Study:

• To develop and validate a novel, accurate, sensitive, and high-throughput screening strategy for amino acid overproducers.
• To leverage the phenomenon of codon usage bias for the development of a rare-codon-rich marker system.
• To provide an alternative to analog-based screening methods for strain improvement.

Main Methods:

• The strategy utilizes rare-codon-rich markers by replacing common codons with synonymous rare alternatives in reporter genes (e.g., antibiotic resistance, fluorescent proteins).
• The system is based on the principle that rare codon translation is dependent on rare transfer RNAs (tRNAs), which are restored by amino acid overproduction.
• Screening involves identifying strains where protein expression is restored in the presence of rare codons, indicating amino acid overproduction.

Main Results:

• Incorporation of rare codons significantly hinders protein expression.
• Protein expression levels positively correlate with intracellular amino acid concentrations.
• The rare-codon-based system successfully screened amino acid overproducers from mutation libraries.
• The method demonstrated high accuracy, sensitivity, and throughput compared to conventional techniques.

Conclusions:

• The rare-codon-based strategy offers an accurate, sensitive, and high-throughput alternative for screening amino acid overproducers.
• This approach simplifies the screening process, requiring only a single modified gene.
• The developed system enhances the likelihood of identifying superior production strains for industrial applications.