Characterization of thermostable amylases of the mid intestine gland of Ucides Cordatus and its potential use as an enzymatic biosensor for mercury

Abstract

Amylases are enzymes that represent approximately 25% of the global enzymatic market, presenting a widespread biotechnological application. This study aimed at extracting, purifying, and characterizing the amylases from the mid intestine gland (MIG) of Ucides cordatus to evaluate their sensitivity to metallic ions as a source of enzymes for environmental monitoring. The crude extract obtained from the MIG was subjected to a partial two-step purification: thermal treatment and precipitation with ammonium sulfate in two fractions (F1: 0-30% and F2: 30-60%). F2 was incubated in different substrates. After observing the high amylolytic activity in this fraction when compared to the other substrates, characterization was performed. The optimum temperature for F2 varied between 45 and 55ºC and the optimum pH between 6 and 7. Protein molecular masses for F2 were estimated to be between 30-34 kDa. F2 amylolytic activity was activated in the presence of 0.0001 mM of Cu+2 (14.5%), Mg+2 (13.29%), Na+ (12.66%), Ca+2 (11.04%), Fe+2 (6%) and inhibited by 0.0001 mM of Cd+2 (22.38%) and Hg+2 (95%). Due to having its activity strongly inhibited by mercury, we suggest the potential use of this fraction as a biological component as a biosensor for heavy metal monitoring.