[Efficient production of L-asparaginase in by optimizing expression elements and host].

L-asparaginase (L-ASN) is widely applied in the treatment of malignant tumor and low-acrylamide food production, however, the low expression level hampers its application. Heterologous expression is an effective strategy to increase the expression level of target enzymes, and is generally used as the host for efficient production of enzymes. In this study, the expression level of L-asparaginase in was enhanced through optimization of expression element and host. Firstly, five signal peptides (SP, SP, SP, SP and SP) were screened, among which SP showed the best performance, reaching an activity of 157.61 U/mL. Subsequently, four strong promoters (P43, P, P and P) from were screened, and tandem promoter P showed the highest yield of L-asparaginase, which was 52.94% higher than that of control strain. Finally, three expression hosts ( Δ0F3 and BL10, WB800) were investigated, and the maximum L-asparaginase activity, 438.3 U/mL, was reached by BL10, which was an 81.83% increase compared with that of the control. This is also the highest level of L-asparaginase in shake flask reported to date. Taken together, this study constructed a strain BL10/P-SP-ansZ capable of efficiently producing L-asparaginase, which laid the foundation for industrial production of L-asparaginase.