Enhanced Expression of Recombinant Cephalosporin Acylase in Escherichia coli via Autoinduction Medium

The large-scale synthesis of β-lactam antibiotics, particularly cephalosporins, relies heavily on the industrial production of recombinant cephalosporin acylase (CCA). This study aimed to identify the most suitable Escherichia coli host strain for CCA production. The selected strain was then used for optimizing medium components and culture conditions using an autoinduction medium in shaking flask fermentation. Initially, three E. coli strains were evaluated: BL21(DE3), BL21(DE3) RIPL, and B(DE3) Origami, to determine the most efficient host for recombinant CCA expression. Among the tested conditions, the autoinduction medium proved particularly effective, contributing to a significant improvement in enzyme yield and serving as the basis for subsequent optimization experiments. To identify the key factors influencing CCA production, a Plackett-Burman design was employed to screen medium components and fermentation parameters, with E. coli BL21(DE3) as the most optimal expression host. The significant variables were then optimized using a Central Composite Design, which resulted in a maximum enzyme activity of 53.3 U/mL under the following conditions: 0.78 g/L glucose monohydrate, 1.12 g/L glycerol, 6.21 mL/L trace elements, and an enzyme expression time of 19.48 h. The optimized conditions led to a 3.8-fold increase in CCA activity compared to unoptimized conditions. These findings provide valuable insights into efficient recombinant CCA production and have important implications for its industrial application in antibiotic synthesis.