1. Catalytic reduction was carried out with fresh (wet) Ca-5-keto-D-gluconate preparation isolated from the fresh broth, and it was found that Ca-L-idonate was obtained in a good yield, 94%. 2. The Ca-L-idonate thus obtained was studied for the confirmation of its properties by paper chromatography, potentiometric titration and by the change of specific rotation corresponding to the lactone formation.
