Abstract: L-phenylalanine is one of the eight essential amino acids and plays an important role in human metabolism. Now the production of L-Phe technology cannot satisfy the demand of the market. Therefore, the goal of this study is to improve the yield of L-phe by using reombinant DNA technology and the method of microorganism fermentation. In the process of the study, a gene pool was established by using error-prone PCR to carry out point mutation of rpoA gene. The amount of L-phe produced by the engineered strain was regulated by the mutation acting on the normal transcription of rpoA. Plasmid ptrc99a was used as a vector to transfer into competent cells, and high-yield strains were screened from it. The plasmid was constructed, screened, validated, and verified and a series of tests were used to state the feasibility of this method in this process. The experimental results showed that the engineered strain was successfully constructed and this study provides scientific basis for L-Phe large-scale production.

Key words: L-Phenylalanine, DNA recombination, screening, fermentation