Production of D-psicose via whole cell conversion at high temperature by using thermostable D-psicose 3-epimerase

Rare sugars, defined by the International Society of Rare Sugars (IRIS), exist in nature as monosaccharides but are present in only limited quantities. Recently, rare sugars have received considerable attention because of its various clinical effects and specific biological functions. Likewise, D-psicose (D-ribo-2-hexulose or D-allulose), a C-3 epimer of D-fructose, also has many uses which include reducing intra-abdominal fat accumulation, protecting pancreas beta-islets and improving insulin sensitivity. Especially, D-psicose has only 0.3% calories compared with sucrose, while it has 70% relative sweetness. In 2012, D-psicose was approved as a food additive and designated as generally recognized as safe (GRAS) by Food and Drug Administration (FDA). Despite such abundant advantages, it has difficulty getting in nature and producing artificially. Recently, the biological production of D-psicose from D-fructose using D-psicose 3-epimerase (DPE) has been used. But, there are only few studies on DPE. So, inhere, a new DPE that has a great advantage on thermostability was expressed in Corynebacterium glutamicum designated as GRAS. Then, whole cell bioconversion reaction of D-fructose to D-psicose was performed in a high temperature range. This work was supported by a grant from the Next-Generation BioGreen 21 Program (SSAC, grant# : PJ00948601), RDA, Korea