title: Whole cell biosynthesis of a functional oligosaccharide, 2'-fucosyllactose, using engineered Escherichia coli.
abstract: BACKGROUND
  2'-Fucosyllactose (2-FL) is a functional oligosaccharide present in human milk which protects against the infection of enteric pathogens. Because 2-FL can be synthesized through the enzymatic fucosylation of lactose with guanosine 5'-diphosphate (GDP)-l-fucose by α-1,2-fucosyltransferase (FucT2), an 2-FL producing Escherichia coli can be constructed through overexpressing genes coding for endogenous GDP- l-fucose biosynthetic enzymes and heterologous fucosyltransferase.
  
  
  RESULTS
  The gene for FucT2 from Helicobacter pylori was introduced to the GDP-l-fucose producing recombinant E. coli BL21 star(DE3) strain. However, only small amount of 2-FL was produced in a batch fermentation because the E. coli BL21star(DE3) strain assimilated lactose instead of converting to 2-FL. As an alternative host, the E. coli JM109(DE3) strain which is incapable of assimilating lactose was chosen as a 2-FL producer. Whole cell biosynthesis of 2-FL from lactose was investigated in a series of batch fermentations using various concentrations of lactose. The results of batch fermentations showed that lactose was slowly assimilated by the engineered E. coli JM109(DE3) strain and 2-FL was synthesized without supplementation of another auxiliary sugar for cell growth. A maximum 2-FL concentration of 1.23 g/l was obtained from a batch fermentation with 14.5 g/l lactose. The experimentally obtained yield (g 2-FL/g lactose) corresponded to 20% of the theoretical maximum yield estimated by the elementary flux mode (EFM) analysis.
  
  
  CONCLUSIONS
  The experimental 2-FL yield in this study corresponded to about 20% of the theoretical maximum yield, which suggests further modifications via metabolic engineering of a host strain or optimization of fermentation processes might be carried out for improving 2-FL yield. Improvement of microbial production of 2-FL from lactose by engineered E. coli would increase the feasibility of utilizing 2-FL as a prebiotic in various foods.
authors.affiliation: Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
authors.forename: Won-Heong
authors.initials: WH
authors.lastname: Lee
authors.forename: Panchalee
authors.initials: P
authors.lastname: Pathanibul
authors.forename: Josh
authors.initials: J
authors.lastname: Quarterman
authors.forename: Jung-Hyun
authors.initials: JH
authors.lastname: Jo
authors.forename: Nam Soo
authors.initials: NS
authors.lastname: Han
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Miller
authors.forename: Yong-Su
authors.initials: YS
authors.lastname: Jin
authors.forename: Jin-Ho
authors.initials: JH
authors.lastname: Seo
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism*; D005285:Fermentation; D005647:Fucosyltransferases / Q000235:genetics / Q000378:metabolism; D005818:Genetic Engineering; D006154:Guanosine Diphosphate Fucose / Q000096:biosynthesis; D016480:Helicobacter pylori / Q000201:enzymology / Q000235:genetics; D007218:Industrial Microbiology / Q000379:methods*; D007785:Lactose / Q000378:metabolism; D009844:Oligosaccharides / Q000096:biosynthesis*; D014312:Trisaccharides / Q000096:biosynthesis*
chemical_list: D001426:Bacterial Proteins; D009844:Oligosaccharides; D014312:Trisaccharides; D006154:Guanosine Diphosphate Fucose; D005647:Fucosyltransferases; D007785:Lactose; C031420:2'-fucosyllactose