Properties of the recombinant alpha-glucosidase from Sulfolobus solfataricus in relation to starch processing

An a-glucosidase activity EC 3.2.1.20 isolated from Sulfolobus solfataricus strain MT-4 was characterised and found of interest at industrial level in the saccharification step of hydrolysis process of starch. The gene encoding for the enzyme was expressed in Escherichia coli BL21 DE3 with a yield of 87.5 Urg of wet biomass. The recombinant cytosolic enzyme was purified to homogeneity with a rapid purification procedure employing only steps of selective and progressive thermal precipitations with a final yield of 75.4% and a purification of 14.5-fold. The properties of this thermophilic a-glucosidase were compared with those of the a-glucosidase of a commercial preparation from Aspergillus niger used in the starch processing.