Here we report for the first time heat of ionization of invertase (E.C.3.2.1.26) active site residues from hyper-producer strain of Aspergillus niger (34.1 U ml(-1)), along with its physiochemical properties, kinetics and thermodynamics of stability-function. The Invertase showed great potential for industry as being highly efficient (k(cat) = 24167 s(-1) at 65 degrees C, pH 5.0) and stable (half life= 12 h at 56 degrees C).