Improved purification of α-amylase isolated fromRhizomucor pusillus by affinity chromatography

Abstract

A highly purified extracellular α-amylase was isolated fromRhizomucor pusillus with minimum loss of enzymatic activity. The enzyme was purified from the mycelium-free liquid filtrate of the thermophilic moldRhizomucor pusillus. Maximum enzyme yields were attained after 5 days of growth on liquid starch-yeast extract at 45°C and pH 7.0. The crude enzyme preparation was first concentrated 80-fold by ultrafiltration. Purification was recently achieved with high-performance liquid chromatography and Waters Protein Pak 300 SW. Improved purification was then achieved with a dextrin-bound affinity column, with a 59-fold increase in specific activity from the crude enzyme preparation. This final enzyme preparation produced a single band on polyacrylamide gel electrophoresis. The molecular weight determined by SDS gel electrophoresis was 52,000 daltons.