Anticancer Efficacy of Purified Extracellular L-asparaginase from Aspergillus niger and Yield Enhancement by Agro-industrial Wastes

Abstract

Nowadays L-asparaginase enzyme is of great importance medically as an anticancer agent and in the food industry through acrylamide mitigation so this work aimed to screen thirty-one fungal isolates recovered from rhizosphere soil by using the dilution plate method for L-asparaginase production. Twenty-four isolates (77.4%) were L-asparaginase producers. Aspergillus niger and A. quadrilineatus were the highest producers with enzyme activity 9.808±0.18930 and 7.348±0.12328 U/ml, respectively. The optimum conditions for enzyme production were at 30 °C for 72 h, pH 6 at 160 rpm, and 0.1% of KH2PO4 in presence of 2% glucose and 1.5% sucrose as carbon source and 1% L-asparagine by A. niger and A. quadrilineatus, respectively. Ammonium sulfate precipitation, Sphedax G-200, and SDS-PAGE were performed for L- asparaginase purification and molecular weight determination. Purified L-asparaginase molecular weights were approximately 50.36 KDa from A. niger with specific activity 50.4 U/mg and 27.8 KDa from A. quadrilineatus with specific activity 37.4 U/mg. Purified L-asparaginase significantly inhibited the proliferation of HCT-116, HePG-2, and MCF-7cell lines with IC50 concentrations of 28.9, 36.1, and 82.6 µg/ml, respectively and did not exhibit any antibacterial efficacy. Enhancement of L-asparaginase production using agro-industrial wastes was evaluated. Maximum yield (23.548 ± 0.00000 U/ml) was obtained by cultivation of A. niger on a mixture of onion and pomegranate peels powder (50%: 50% w/w) and cultivation of A. quadrilineatus on pomegranate peels only.