Improving Expression of Pepsinogen A from Homo sapiens in Aspergillus niger by Using a Multi-Copy Gene Knock-in Strategy

Pepsinogen A (PGA) plays an important role in the treatment of human gastrointestinal diseases. At present, PGA is mainly extracted from pig stomach, so its source very limited and price expensive. Production by microbial fermentation using engineered strain with high yield would be ideal solution. This paper presents a new system for high-level expression Homo sapiens (hPGA) Aspergillus niger. The hPGA5 gene codon was optimized according to bias A. niger then connected strong promoter signal peptide construct cassette. An ingenious multi-copy knock-in strategy mediated CRISPR/Cas9 tool used improve production hPGA By optimizing copy number integration sites gene, engineering constructed. After shake-flask 7 d, enzyme activity recombinant reached 542.3 U/mL, which highest known activity. lays foundation fermentation.