title: Co-expression of D-glucose isomerase and D-psicose 3-epimerase: development of an efficient one-step production of D-psicose.
abstract: D-Psicose has been attracting attention in recent years because of its alimentary activities and is used as an ingredient in a range of foods and dietary supplements. To develop a one-step enzymatic process of D-psicose production, thermoactive D-glucose isomerase and the D-psicose 3-epimerase obtained from Bacillus sp. and Ruminococcus sp., respectively, were successfully co-expressed in Escherichia coli BL21 strain. The substrate of one-step enzymatic process was D-glucose. The co-expression system exhibited maximum activity at 65 °C and pH 7.0. Mg(2+) could enhance the output of D-psicose by 2.32 fold to 1.6 g/L from 10 g/L of D-glucose. When using high-fructose corn syrup (HFCS) as substrate, 135 g/L D-psicose was produced under optimum conditions. The mass ratio of D-glucose, D-fructose, and D-psicose was almost 3.0:2.7:1.0, when the reaction reached equilibrium after an 8h incubation time. This co-expression system approaching to produce D-psicose has potential application in food and beverage products, especially softdrinks.
authors.affiliation: National Engineering Laboratory for Industrial Enzymes, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Men
authors.affiliation: National Engineering Laboratory for Industrial Enzymes, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China.
authors.forename: Yueming
authors.initials: Y
authors.lastname: Zhu
authors.affiliation: National Engineering Laboratory for Industrial Enzymes, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Zeng
authors.affiliation: National Engineering Laboratory for Industrial Enzymes, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China.
authors.forename: Ken
authors.initials: K
authors.lastname: Izumori
authors.affiliation: National Engineering Laboratory for Industrial Enzymes, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China. Electronic address: syx0430@hotmail.com.
authors.forename: Yuanxia
authors.initials: Y
authors.lastname: Sun
authors.affiliation: National Engineering Laboratory for Industrial Enzymes, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China.
authors.forename: Yanhe
authors.initials: Y
authors.lastname: Ma
mesh_terms: D019747:Aldose-Ketose Isomerases / Q000235:genetics / Q000378:metabolism*; D001407:Bacillus / Q000201:enzymology / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D002238:Carbohydrate Epimerases / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D005632:Fructose / Q000096:biosynthesis* / Q000737:chemistry; D005798:Genes, Bacterial; D005947:Glucose / Q000378:metabolism; D066248:High Fructose Corn Syrup / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007218:Industrial Microbiology; D007700:Kinetics; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D045857:Ruminococcus / Q000201:enzymology / Q000235:genetics; D013237:Stereoisomerism; D013379:Substrate Specificity; D013549:Sweetening Agents / Q000378:metabolism; D013696:Temperature
chemical_list: D001426:Bacterial Proteins; D066248:High Fructose Corn Syrup; D011994:Recombinant Proteins; D013549:Sweetening Agents; C003243:psicose; D005632:Fructose; D002238:Carbohydrate Epimerases; D019747:Aldose-Ketose Isomerases; C023298:xylose isomerase; D005947:Glucose
keywords: Co-expression; High-fructose corn syru p(HFCS); d-Glucose isomerase; d-Psicose; d-Psicose 3-epimerase