Selection of Recombinant Bacteria with High L-Asparaginase Production through Normal Pressure and Room Temperature Plasma Mutagenesis

capable of secreting and expressing L-ASNase was constructed, and the enzyme production of the recombinant bacterium was further increased through normal pressure and room temperature plasma mutagenesis. After fermentation of recombinant Bacillus subtilis WB600 (pMA5-wapA-ansZ) for 30 h, the extracellular enzyme activity reached 37.2 U/mL, indicating that L-ASNase can be secreted out of the cell mediated by the signal peptide wapA. Plasma mutagenesis was performed on the recombinant bacteria under the mutagenesis operating conditions of 120 W power, 10 L/min air flow, and 40 s mutagenesis time.

The enzyme activity of the mutant strain reached a maximum of 48.4 U/mL, which was increased by 30% before mutation. The above results show that normal pressure and room temperature plasma mutagenesis can effectively improve the enzyme activity of L-ASNase produced by recombinant bacteria. The research results provide an efficient production strain for the industrial production of L-ASNase.