title: [Producing human lactoferrin by high-density fermentation recombinant Pichia pastoris].
abstract: BACKGROUND
  To evaluate expression of human lactoferrin gene by high-density fermentation in recombinant Pichia pastoris on the premise of maintaining its biological activities.
  
  
  METHODS
  The neutrophil was isolated from human peripheral blood and its total RNA was prepared. Full-length cDNA of human lactoferrin gene was then obtained by RT-PCR, cloned into expression vector pPIC 3.5 K and transformed into Pichia pastoris strain KM71. With two-layer filter method, the transformants with high-productivity of human lactoferrin were screened out into fed-batch high-density fermentation. And later, the physical, chemical and biological activities of fermentation product were detected preliminarily.
  
  
  RESULTS
  The strain p3.5-k-7 with better productivity of human lactoferrin was screened out into fed-batch high-density fermentation. The fermentation lasted nearly for nine days, with A-600 of culture once above 260 and the highest productivity of human lactoferrin being 115 mg/L, 7.67 times the amount of that in shake flask cultivation.
  
  
  CONCLUSIONS
  The authors successfully realized high-density fermentation expression of human lactoferrin gene in recombinant Pichia pastoris.
authors.affiliation: Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 100052, China.
authors.forename: Ge
authors.initials: G
authors.lastname: Ying
authors.forename: Shu-hua
authors.initials: SH
authors.lastname: Wu
authors.forename: Jing
authors.initials: J
authors.lastname: Wang
authors.forename: Xiao-dong
authors.initials: XD
authors.lastname: Zhao
authors.forename: Jian-ming
authors.initials: JM
authors.lastname: Chen
authors.forename: Xiao-guang
authors.initials: XG
authors.lastname: Zhang
authors.forename: Yun-de
authors.initials: YD
authors.lastname: Hou
mesh_terms: D003001:Cloning, Molecular; D005285:Fermentation; D006801:Humans; D007781:Lactoferrin / Q000096:biosynthesis* / Q000235:genetics; D010843:Pichia / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000096:biosynthesis*
chemical_list: D011994:Recombinant Proteins; D007781:Lactoferrin