Optimization of L-asparaginase type II produced by Bacillus velezensis SE114

Once the acute lymphoblastic leukemia cells that need L-asparagine are exposed to L-ASNase, they die because of the limitations of L-asparagine. The globally rising rate of ALL also requires extraordinary efforts to discover new microorganisms with high L-ASNase production and efficiency. The aim of this study is the high amount of L-ASNase production. After isolation, the L-ASNase production was optimized using the response surface methodology and the central composite design. Then, in-silico studies were predicted for the L-ASNase-producing gene. In this study, Bacillus velezensis was isolated as an L-ASNase producer from slaughterhouse effluent using the M9 medium. The optimization process further illustrated Tween 20, glucose, temperature, and L-asparagine, which were more significant for L-ASNase production. Based on statistical prediction by response surface methodology, more enzyme activity (7.11 U/mL) could be realized at 0.6% Tween 20, 1.7% glucose, 55°C temperature, and 1.8% L-asparagine. The in-silico studies also established that the binding site is located at the N-terminal domain and the active site flexible loop. Additionally, it contained Thr36, Ala47, Tyr50, Glu84, Asp117, Thr116, Met142, Lys189, Thr193, and Thr192 as the conserved and functional residues in L-ASNase. It was concluded that B. velezensis SE114  produced L-ASNase type II in the present study. The statistical optimization results also showed that Tween 20, glucose, temperature, and L-asparagine were significant variables affecting the L-ASNase production. In addition, temperature and L-asparagine had noteworthy interactions.

Optimization of L-asparaginase type II produced by Bacillus velezensis SE114 Keywords:

L-Asparaginase , Bacillus velezensis , Optimization , Response surface methodology , Central Composite Design