earticle

영어

D-Psicose, a rare keto-hexose, are not abundant in nature and are difficult to prepare by chemical methods. D-Psicose has sweet taste like general sugars, but calorie is near to
zero because it is not metabolized in the human body. For the production of D-psicose,
we used allulose-6-phosphate 3-epimerase of Escherichia coli and D-tagatose 3-epimerase of Agrobacterium tumefeciens. In order to use the allulose-6-phosphate 3-epimerase, E. coli was transformed with pTalsE containing alsE. Fructose-6-phosphate of glycolysis pathway might be epimerized to psicose-6-phosphate by alsE. The pfkA gene encoding 6-phosphofructokinase of glycolysis was deleted to make the psicose producing E. coli blocking use of fructose, and allose operon, including alsE, alsI, alsK, alsA, alsB, alsC and alsR genes, was deleted. When E. coli (
pfkA, als2) harboring pTalsE was cultivated in 2YT medium with 30g/ℓ of glucose and fructose, 0.5 and 1g/ℓ of D-psicose was obtained approximately, respectively. The other scheme for production of D-psicose was performed with D-tagatose 3-epimerase by which fructose was epimerized to D-psicose. When recombinant E. coli (
pfkA, als2) harboring pTPE with Atu4750 was cultivated in 2YT medium containing 30g/ℓ of fructose, D-psicose was
obtained upto 6g/ℓ. This work was supported by the 21C Frontier Microbial Genomics and Applications Center Program, EB-NCRC (Grant No. R15-2003-012-02001-0), Brain Pool program and BK21 program of Korea.