Design of 5′-UTR to Enhance Keratinase Activity in Bacillus subtilis

Keratinase is an important industrial enzyme, but its application performance limited by low activity. A rational design of 5′-UTRs that increases translation efficiency approach to enhance protein expression. Herein, we optimized the 5′-UTR recombinant keratinase KerZ1 expression element secretory activity in Bacillus subtilis WB600 through Spacer design, RBS screening, and sequence simplification. First, A/U content was increased site-directed saturation mutation G/C bases, secreted mutant strain B. WB600-SP 7.94 times higher than KerZ1. Subsequently, WB600-SP-R further 13.45 based on prediction multi-site screening. Finally, WB600-SP-R-D reached 204.44 KU mL−1 reducing length 5′ end 5′-UTR, which 19.70 In a 5 L fermenter, after 25 h fermentation 797.05 mL−1, indicated high production intensity. Overall, strategy this study obtained mutants will provide good reference for regulation other enzymes.