Background: L-asparaginase is one of the most widely used chemotherapeutic agents for
the treatment of a variety of lymphoproliferative disorders and particularly acute lymphoblastic leukemia.
Due to increased applications of L-asparaginase in several industrial fields including food processing
and medical fields, its production needs to be increased to several folds.
Objectives: The aim was (i) to identify the significant factors which affect L-asparaginase production
by Streptomyces fradiae NEAE-82 and (ii) to achieve higher production of L-asparaginase.
Methods: Sixteen assigned factors and three dummy factors were screened using Plackett-Burman experimental
design to determine the most important factors for the production of L-asparaginase by
Streptomyces fradiae NEAE-82.
Results: L-asparagine was determined to be the most significant positive independent factor (P-value
0.0092) affecting L-asparaginase production by Streptomyces fradiae NEAE-82 followed by pH and
NaCl with significant P-values of 0.0133 and 0.0272; respectively. These factors were further optimized
by Box-Behnken experimental design. The optimized fermentation conditions, which resulted in
the maximum L-asparagine activity of 53.572 UmL-1 are g/L: dextrose 4, L-asparagine 15, KNO3 2,
MgSO4.7H2O 0.5, K2HPO4 1, FeSO4.7H2O 0.02, NaCl 0.2, ZnSO4 0.01 and inoculum size 2 %, v/v for
7 days incubation at temperature 37°C, agitation speed 100 rpm, pH 8.5.
Conclusion: A total of 3.41-fold increase in the production of L-asparaginase was achieved in the medium
after statistical improvement (53.572 UmL-1) as compared to the unoptimized basal medium used
prior to the application of Plackett-Burman (15.704 UmL-1).