Efficient secretory system of Corynebacterium glutamicum by optimization and modification of expression elements and cell wall structure
摘要
Corynebacterium glutamicum is a safe strain with great potential for industrial applications, but more research is needed on secretory expression systems. Here, we constructed a non-inducible secretory expression system of the strain. By building a signal peptide library, we screened several Sce-type signal peptides and analyzed the relationship between their constitutive properties and secretory efficiency. To further meet the safety requirements in industrial applications, fifteen constitutive promoters were screened, and protein expression was optimized by promoter tandem strategy. In the WYJ1, WYJ2, WYJ3, and WYJ4 engineering strains, we confirmed that the modification of cell permeability favored protein secretion. The engineering strains WYJ2P35SP35 and WYJ4P35SP35 were scaled up for culture, and their extracellular enzyme activities and proteins reached 26.42 U/mL and 19.65 mg/L, and 23.97 U/mL and 13.84 mg/L, respectively. This secretory expression system increases the potential of industrial applications of Corynebacterium glutamicum and lays the foundation for applications.