Antioxidant potential of L-asparaginase and L-glutaminase excreted by Monascus sp.

Abstract

The L-asparaginases and L-glutaminases can be excreted by various organisms such as bacteria and fungi, but also by animal and plant tissues. Studies indicate that these enzymes can be used in the food industry to improve the flavor of foods and in pharmaceuticals as an ally in the treatment of some types of cancer. This article aimed to select a fungal strain that produces these amidohydrolases, investigate the potential production of said enzyme by submerged fermentation and whether the partially purified enzyme has biological activities. Initially, 19 fungal strains were selected by Submerged Fermentation in modified Czapek's Dox medium. The best extracellular enzyme producer, Monascus sp., was tested in Solid State Fermentation and Supplemented Submerged Fermentation, and enzymes extracted both extracellularly and intracellularly. The best yield of Monascus sp. was in Submerged Fermentation supplemented with glutamine (1% v/v), glucose (1% v/v) and meat extract (1% v/v), at pH 7.0 at 30 °C for 72h. Partial purification of the crude extract by ion exchange chromatography (DEAE SP) resulted in 19 fractions that were evaluated for their ability to hydrolyze glutamine and asparagine as substrate. The determination of the antioxidant activity was carried out, which presented an IC50 of 11.83 mg/mL by the DPPH method and 2.87 mg/mL by the ABTS method. In that study it was observed that Monascus sp. was able to excrete these amidohydrolases with affinities to hydrolyze glutamine and asparagine. Despite presenting good antioxidant activity, more studies must be carried out to determine its biotechnological potential.