Background: L-asparaginase (L-AsnA) enzyme has gained significant attention in the
food, biocatalysts and pharmaceutics industry. It (L-AsnA) has been widely used in food processing
industries as a promising acrylamide mitigating agent and as a therapeutic agent in the treatment
of certain human cancers.
Objective: Based on US Patent (4,433,054; 1984), L-asparaginase (L-AsnA) enzyme is immobilized
by admixing the active enzyme on the polysaccharide to be in a gel form. The storage stability
of immobilized L-AsnA enzyme and its anti-proliferation and antiviral activity were determined.
Methods: In the present study, S. maxima was cultured at large scales (300 liter) for the production
of enough extracellular L-asparaginase (L-AsnA) using modified (high N concentration) Zarrouk
medium as we reported in a previous study. L-AsnA was immobilized on natural polymers,
as agar cake beads, agarose pieces and gelatin blocks, in order to evaluate the efficiency of physical
entrapment techniques. Anti-proliferation properties of L-AsnA against lung carcinoma A549,
hepatocellular carcinoma Hep-G2 and prostate carcinoma PC3 human cancer cell lines were assessed
by the MTT cell viability method. In addition, the antiviral activity against Coxsackie B3
(CSB3) Virus was assessed.
Results: The highest L-AsnA immobilized activity and immobilization yield were achieved with
agar cakes bead. The purified S. maxima L-AsnA showed good antiviral activity against Coxsackie
B3 (CSB3) Virus in a dose-dependent manner with an IC50 value 17.03 μg/ml. The antiviral
mode of action is presumably due to their capability of inhibiting attachment, blocking the adsorption
and penetration event of the viral replication cycle with 89.24%, 72.78% and 72.78%, respectively.
Also, S. maxima L-AsnA showed anti-proliferation effect against lung carcinoma A549,
hepatocellular carcinoma Hep-G2 and prostate carcinoma PC3 human cancer cell lines, with an
IC50 of 22.54, 24.65 and 56.61 μg/ml, respectively.
Conclusion: It is interesting to favor L-asparaginase of S. maxima which showed antiviral activity
and anti-proliferation effect against different types of human cell lines. Thus, S. maxima microalgae
might be a good source for L-AsnA enzymes and can be immobilized on natural polymers.