L-asparaginase from Aspergillus oryzae spp.: effects of production process and biochemical parameters

L-asparaginases prevent the formation of acrylamide, a substance commonly found in foods subjected to heat and that also contains reducing sugars and L-asparagine. This work aimed to select a strain of Aspergillus spp. able to produce L-asparaginase and to optimize the fermentation parameters, the partial purification and biochemical characterization were also performed. The Aspergillus oryzae IOC 3999 was selected due to its greater enzymatic activity: 1443.57 U/mL of L-asparaginase after 48 h of fermentation. The optimized conditions allowed for an increase of 223% on the L-asparaginase production: 2.9% lactose, 2.9% L-asparagine and 0.7% hydrolyzed casein, 0.152% KH2PO4, 0.052% KCl and MgSO4, 0.001% of CuNO3.3H(2)O, ZnSO4.7H(2)O and FeSO4.7H(2)O adjusted to pH 7.0; added a concentration of 5.05x10(6) spores/mL at 30 degrees C for 100 rpm. A purification factor of 2.11 was found and the molecular mass was estimated at 20.8 kDa. The enzyme showed optimum activity at 60 degrees C and pH 5 and stability at 50 degrees C for 1 h. The enzyme presented desirable biochemical characteristics, mainly the acid pH stability, indicating that the enzyme would work well in food matrices due to the closeness of pH, meaning that it could be a potential option for use in the food industry.

Automated summary

The study selected Aspergillus oryzae IOC 3999 strain for its high L-asparaginase activity, and optimized fermentation parameters and purification processes to achieve a significant increase in L-asparaginase production. The enzyme showed desirable biochemical characteristics, with stability at acid pH indicating its potential use in food industry.