Evidence for the improvement of thermostability of the maltogenic a-amylase of Aspergillus niger by negative pressure

摘要

Thermostability of the enzymes is influenced by the different parameters and pressure also influences the biological activity of the enzymes. Recently reported maltogenic a-amylase from Aspergillus niger acts optimally on starch at 40°C and it was unstable above 40°C at atmospheric pressure. Calcium could stabilize the maltogenic a-amylase activity up to 50°C at atmospheric pressure. But, at negative pressure (-200 mbar) enzyme was stable at temperatures higher than 50°C either in the presence orabsence of the substrate, starch making it adoptable for starch processing. Enzyme showed higher affinity to the starch at negative pressure compared to the atmospheric pressure and change in the surface roughness of the enzyme is almost similar to thenative state at 70°C and negative pressure. These results suggest that thermolabile enzymes can be used at negative pressures for industrial applications.