Abstract: Problem: To develop a method for producing a novel sweetener containing glucose, fructose, and psicose, which is produced from glucose liquid sugar using an isomerase and an epimerase; use of the novel sweetener as a food or drink material; and a novel sweetener capable of preventing obesity caused by the intake thereof. Means of Resolution: An isomerase and an epimerase are allowed to act on glucose liquid sugar produced in a glucose liquid sugar production plant to thereby produce D-psicose, thereby providing a novel sweetener (product) that maintains the degree and quality of sweetness of a glucose-fructose mixed solution and never causes obesity, a method for producing the same, and use of the same.

Abstract: Problem: To provide a microorganism with an ability to produce deoxy polyol dehydrogenase. Means for Resolution: A microorganism belonging to genus Enterobacter with an ability to produce a dehydrogenase for deoxy polyol of the same structure at the positions C2 and C3 as that of ribitol or L-iditol. The bacterial cell IK7 of the genus Enterobacter (accession No. NITE P-271). A method for producing deoxy ketose comprising allowing a culture containing the deoxy polyol dehydrogenase obtained by the culturing of the microorganism of the invention or allowing the deoxy polyol dehydrogenase to react with a solution containing deoxy polyol of the same structure at the positions C2 and C3 as that of ribitol or L-iditol to oxidize deoxy polyol to produce the corresponding deoxy ketose and then collecting the deoxy ketose. The deoxy polyol is 1-deoxy-D-allitol, while the corresponding deoxy ketose is 1-deoxy-L-psicose.

Abstract: Providing 1- or 6-deoxy products corresponding to all of aldohexoses, ketohexoses and sugar alcohols, as based on Deoxy-Izumoring, as well as a method for systematically producing those products. A method for producing deoxyketohexose and a derivative thereof using a deoxyketohexose isomerase derived from Pseudomonas cichorii ST-24 (FERM BP-2736), comprising epimerizing 1-deoxy D-ketohexose or 6-deoxy D-ketohexose or 1-deoxy L-ketohexose or 6-deoxy L-ketohexose at position 3 to produce the individually corresponding 1-deoxy D-ketohexose or 6-deoxy D-ketohexose or 1-deoxy L-ketohexose or 6-deoxy L-ketohexose as an intended product.

Abstract: Object: To provide a thermostable L-ribose isomerase. Means for Resolution: The thermostable L-ribose isomerase with MW. 32,000 (by SDS-PAGE), optimal temperature of 45° C., optimal pH of pH 9.0 (glycine-NaOH buffer), and stable physicochemical properties such as temperature stability up to 45° C. during thermal treatment at pH 9.0 for 10 minutes, and with an action to isomerize L-ribose to generate L-ribulose or of inversely to isomerize L-ribulose to generate L-ribose.