Food processing applications of protease activity identified in the methotrexate degrading enzyme of Variovorax paradoxus

Abstract

A 46 kDa dimeric methotrexate (MTX) degrading enzyme was reported from Variovorax paradoxus. This enzyme also showed caseinolytic protease activity. The optimum pH (5.5), and temperature (35 ℃) of protease activity were different from those of MTX degrading activity of the enzyme. Cross linked enzyme aggregates (CLEAs) of the purified soluble protease showed higher activity, higher thermostability, and lower Michaelis–Menten constant (Km) value on casein compared to the soluble enzyme. The soluble enzyme showed casein hydrolysis capacity in the zymogram reactions. The CLEAs could lead to faster milk clotting, lower bread hardness, shorten dough forming time, and increased dough and bread volumes compared to the soluble enzyme, which could be due to the higher affinity of CLEAs to the proteins over soluble enzyme. Majority of the panellists given ‘excellent’ in the five-point scale starting from ‘not satisfactory’ to ‘excellent’ to the CLEAs treated cheese, and bread samples compared to the soluble enzyme treated samples with respect to flavor, texture, and taste. These results suggest that CLEAs are advantageous over soluble enzyme during food processing applications.