Cephalosporin C acylases (CCAs) catalyze the hydrolysis of cephalosporin C to 7-aminocephalosporanic acid, a key intermediate for semisynthetic cephalosporin antibiotics. The functional secretion of heterologous CCAs in Escherichia coli is often constrained by signal peptide efficiency. To enhance the production of the engineered CCA mutant A14 from Bosea sp. OK403, we performed systematic signal peptide screening and identified the native SP AsPGA as most effective. Following codon optimization to generate SP AsPGA∗ , targeted mutagenesis of its N-, H-, and C-regions produced the superior H9 mutant (C16A). This variant increased extracellular A14 expression and activity by 6.26-fold and 2.0-fold, respectively. Molecular dynamics simulations indicated the C16A substitution stabilizes the signal peptide conformation and facilitates SecA translocon interaction. This work establishes that systematic mining and engineering of signal peptides, particularly through mutations that enhance structural stability, is a powerful strategy for optimizing the secretory production of complex enzymes in recombinant systems. Strategy to enhance CPC acylase secretion in Escherichia coli via signal peptide mining, screening, and optimization, followed by structural analysis and molecular dynamics simulations of the resulting mutants.

RE-Ba-Cu-O (REBCO) bulk high temperature superconducting undulators have been experimentally demonstrated to generate undulator fields exceeding 2 T at a 10 mm period, outperforming alternative undulator technologies for short-period applications. This study aims to further enhance undulator performance by reducing the period length through optimization of staggered-array, half-moon-shaped REBCO bulks. We propose a novel dual-lunate-ring-based REBCO undulator geometry that enables control of magnetization currents within individual lunate rings. The coexistence of magnetization currents on both the upper and lower sides of the undulator axis contributes to a significant enhancement of the on-axis magnetic field. To evaluate the performance of this design, the undulator period and gap were fixed at 7 mm and 3.3 mm, respectively, while the dimensions of the bulk rings were optimized numerically using the H-formulation. When the background solenoidal field changes from 10T to zero (ΔBs = 10 T), the undulator is expected to achieve a field strength B0 of 1.65T with a 7 mm period, corresponding to a deflection parameter of K = 1.1.