Optimization of production of anti-tumor l-asparaginase by free and immobilized marine Aspergillus terreus

l-asparaginase plays a vital role in medical application, particularly in treatment of acute lymphoblastic leukemia as an effective anti-tumor agent. In the present study, twenty-one fungal strains were isolated from marine environment of the Red Sea coasts of Egypt. Screening for fungal l-asparaginase production was done, and only five fungal strains were selected and identified as Aspergillus, Penicillium and Fusarium. The most potent fungal isolate was Aspergillus terreus which yielded the highest l-asparaginase specific activity (4.81 U/mg protein). The highest enzyme productivity was observed on the 5th day and the optimized fermentation parameters were pH 6.0, temperature 35 °C. The yield was also high up on using dextrose and asparagine (8.26 U/mg protein) as carbon and nitrogen sources. The cultural conditions were studied using the Plackett–Burman experimental design. Immobilization using A. terreus adsorbed on sponge enhanced the enzyme production by 1.33-fold compared to the conventional free-cells. Repeated reuse of the adsorbed cells achieved the maximum enzyme specific activity after three cycles (33.86 U/mg protein).