Abstract
Penicillium sp.-1 and Aspergillus niger-12, respectively, produced inulinase inducibly and constitutively. The basic cultivation conditions for the production of the enzymes, their enzymological features, their mechanisms of action, etc., were examined for the two fungi. The estimated molecular weights of the extracellular inulinases produced by the two fungi were in the range of 59, 00086, 000, their optimum pH in the range of 4.0-5.3, and their optimum temperature in the range of 40-50°C. Each enzyme was activated by Mn2+, and strongly inhibited by Ag+, Hg2+, Fe3+, EDTA and PCMB. As to substrate specificity, the extracellular P-III enzyme of the Aspergillus niger-12 was a new type of enzyme which specifically acted only on inulin, and did not act on sucrose, raflinose or bacterial levan at all. The enzyme hydrolyzed inulohexaose to inulotriose and inuloheptaose to inuloteraose and inulotriose mainly, and scarcely hydrolyzed the smaller substratesunder DP 4.
