Inulin formation of penicillin producing industrial Penicillium chrysogenum strains

Conidia of certain penicillin producing Penicillium chrysogenum industrial strains produced polyfructose. Two types of polyfructoses were formed by conidia of P. chrysogenum B10 from sucrose and with less yield from raffinose. Ten percent of fructans were in water insoluble form attached to the outer wall of conidia. The other, ethanol precipitable fructan formed a colloid opalescent solution. The latter had inulin type beta (2-->1) bonds--identified by 13C NMR spectroscopy--between fructose molecules and had a molecular weight of 217,000 Daltons. The KM value of sucrose hydrolysis--the first step of inulin production--was 0.86 M. The invertase hydrolysed about 70% of sucrose on the second day. Optimal conditions for inulin formation were: pH 6.0, 25-45 degrees C, 100 mg/ml sucrose, 10(7) spore/ml. The maximum conversion rate of fructose from sucrose into precipitable inulin was about 10% after 48 h incubation. The inulin production could be inhibited by glucose.