title: Genetic engineering of Synechocystis PCC6803 for the photoautotrophic production of the sweetener erythritol.
abstract: BACKGROUND
  Erythritol is a polyol that is used in the food and beverage industry. Due to its non-caloric and non-cariogenic properties, the popularity of this sweetener is increasing. Large scale production of erythritol is currently based on conversion of glucose by selected fungi. In this study, we describe a biotechnological process to produce erythritol from light and CO2, using engineered Synechocystis sp. PCC6803.
  
  
  METHODS
  By functionally expressing codon-optimized genes encoding the erythrose-4-phosphate phosphatase TM1254 and the erythrose reductase Gcy1p, or GLD1, this cyanobacterium can directly convert the Calvin cycle intermediate erythrose-4-phosphate into erythritol via a two-step process and release the polyol sugar in the extracellular medium. Further modifications targeted enzyme expression and pathway intermediates.
  
  
  CONCLUSIONS
  After several optimization steps, the best strain, SEP024, produced up to 2.1 mM (256 mg/l) erythritol, excreted in the medium.
authors.affiliation: Photanol BV, Science Park 408, 1098XH, Amsterdam, The Netherlands. aniek.vanderwoude@photanol.com.
authors.forename: Aniek D
authors.initials: AD
authors.lastname: van der Woude
authors.affiliation: Photanol BV, Science Park 408, 1098XH, Amsterdam, The Netherlands.
authors.forename: Ruth
authors.initials: R
authors.lastname: Perez Gallego
authors.affiliation: Photanol BV, Science Park 408, 1098XH, Amsterdam, The Netherlands.
authors.forename: Angie
authors.initials: A
authors.lastname: Vreugdenhil
authors.affiliation: Photanol BV, Science Park 408, 1098XH, Amsterdam, The Netherlands.
authors.forename: Vinod
authors.initials: V
authors.lastname: Puthan Veetil
authors.affiliation: Photanol BV, Science Park 408, 1098XH, Amsterdam, The Netherlands.
authors.forename: Tania
authors.initials: T
authors.lastname: Chroumpi
authors.affiliation: Photanol BV, Science Park 408, 1098XH, Amsterdam, The Netherlands.
authors.forename: Klaas J
authors.initials: KJ
authors.lastname: Hellingwerf
mesh_terms: D000449:Aldehyde Reductase / Q000235:genetics / Q000378:metabolism; D052818:Autotrophic Processes; D004896:Erythritol / Q000096:biosynthesis*; D004926:Escherichia coli; D005818:Genetic Engineering / Q000379:methods*; D008027:Light; D030781:Organisms, Genetically Modified; D010788:Photosynthesis / Q000235:genetics; D013403:Sugar Phosphates / Q000378:metabolism; D013549:Sweetening Agents / Q000378:metabolism; D046939:Synechocystis / Q000235:genetics* / Q000254:growth & development* / Q000378:metabolism*
chemical_list: D013403:Sugar Phosphates; D013549:Sweetening Agents; C026959:erythrose 4-phosphate; D000449:Aldehyde Reductase; D004896:Erythritol
keywords: Calvin cycle; Cyanobacteria; Erythritol; Erythrose; Erythrose-4-phosphate; Metabolic engineering; Sweetener