Isolation and purification of a new protease from Aspergillus niger LCF no 9

Summary Aspergillus niger LCF N ^o 9 synthesizes large amounts of a semi-alkaline protease highly active on Benzoyl arginine p-nitroanilide (BAPNA) that is likely to find industrial use. An industrial-grade enzyme of around 80% purity was prepared and a reference enzyme was obtained in high yield from the industrial product by ultrafiltration and HPIEC on a mono Q column. The industrial-grade enzyme was produced on a pilot scale with a yield of 0.52% of medium solid starting material by adsorption on CM-Sephadex A₅₀, precipitation with acetone at –30°C, ion-exchange chromatography on DEAE-Sepharose and diafiltration.