The producing organism, strain TP-A0451 was isolated from a stem of bracken, Pteridium aquilinum, collected in Toyama, Japan. The seed culture was incubated in a medium consisting of 1% soluble starch, 0.5% glucose, 0.3% NZ-case, 0.2% yeast extract, 0.5% tryptone, 0.1% K₂HPO₄, 0.05% MgSO₄.7H₂O and 0.3% CaCO₃ (adjusted to pH 7.0 before sterilization) at 30 ℃ for 4 days on a rotary shaker (200rpm). Three-ml aliquots of the seed culture were transferred into thirty 500-ml/K flasks each containing 100 ml of the production medium consisting of 0.5% glucose, 2% glycerol, 2% soluble starch, 1.5% Pharmamedia, 0.3% yeast extract, 1% Diaion HP-20 (adjusted to pH 7.0 before sterilization). Fermentation was carried out for 6 days at 30 ℃ on a rotary shaker (200 rpm).