title: Production of d-psicose from d-fructose by whole recombinant cells with high-level expression of d-psicose 3-epimerase from Agrobacterium tumefaciens.
abstract: The specific activity of recombinant Escherichia coli cells expressing the double-site variant (I33L-S213C) d-psicose 3-epimerase (DPEase) from Agrobacterium tumefaciens was highest at 24 h of cultivation time in Terrific Broth (TB) medium among the media tested. The contents of crude protein and DPEase in recombinant cells at 24 h were 37.0 and 8.6% (w/w), respectively, indicating that the enzyme was highly expressed. The reaction conditions for the production of d-psicose from d-fructose by whole recombinant cells with the highest specific activity were optimal at 60°C, pH 8.5, 4 g/l cells, and 700 g/l d-fructose. Under these conditions, whole recombinant cells produced 230 g/l d-psicose after 40 min, with a conversion yield of 33% (w/w), a volumetric productivity of 345 g/l/h, and a specific productivity of 86.2 g/g/h. These are the highest conversion yield and volumetric and specific productivities of d-psicose from d-fructose by cells reported thus far.
authors.affiliation: Department of Food Science and Technology, Catholic University of Daegu, Gyeongbuk, Gyeongsan 712-702, Republic of Korea.
authors.forename: Chang-Su
authors.initials: CS
authors.lastname: Park
authors.affiliation: Department of Bioscience and Biotechnology, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul 143-701, Republic of Korea.
authors.forename: Chul-Soon
authors.initials: CS
authors.lastname: Park
authors.affiliation: Department of Bioscience and Biotechnology, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul 143-701, Republic of Korea.
authors.forename: Kyung-Chul
authors.initials: KC
authors.lastname: Shin
authors.affiliation: Department of Bioscience and Biotechnology, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul 143-701, Republic of Korea. Electronic address: deokkun@konkuk.ac.kr.
authors.forename: Deok-Kun
authors.initials: DK
authors.lastname: Oh
mesh_terms: D016960:Agrobacterium tumefaciens / Q000201:enzymology* / Q000235:genetics; D002238:Carbohydrate Epimerases / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000166:cytology / Q000235:genetics / Q000378:metabolism*; D005632:Fructose / Q000096:biosynthesis / Q000378:metabolism*; D015870:Gene Expression; D005818:Genetic Engineering; D006863:Hydrogen-Ion Concentration; D013696:Temperature
chemical_list: C003243:psicose; D005632:Fructose; D002238:Carbohydrate Epimerases
keywords: Agrobacterium tumefaciens; High-level expression; Recombinant Escherichia coli; Whole cell reaction; d-Psicose; d-Psicose 3-epimerase