Crystallization and General Properties of an Extracellular Inulase from Aspergillus sp.: (Studies on Microbial Inulase Part IV)

Abstract

An extracellular inulase from Aspergillus niger was purified by Sephadex column chromatography, and was obtained in the crystalline form by ammonium sulfate precipitation. This enzyme hydrolyzed inulin, but not sucrose and raffinose. The main products from inulin were inulotriose, inulotetraose and inulopentaose, whose amounts were much in this order. The enzyme acted scarcely on inulo-oligosaccharides smaller than pentasaccharide, and the pattern of action seems to be endowise. The enzyme showed the maximum activity at pH 5.3 and 45°C, and was activated by divalent metal ions such as Mn2+, whereas was markedly inhibited by Hg2+, Ag+, and PCMB. The Km value for inulin was 1.25 × 10−3M. © 1978, Japan Society for Bioscience, Biotechnology, and Agrochemistry. All rights reserved.