title: [Conditions for large-scale production of genetically engineered E.coli bearing humanized anti- HBsAg Fab].
abstract: OBJECTIVE
  To define the conditions for large-scale production of genetically engineered E.coli bearing humanized anti-HBsAg Fab.
  
  
  METHODS
  Characteristic growth and expression of the engineered E.coli were observed during fermentation in the shaking flask to define the optimal culture conditions to achieve the highest production levels. On the basis of the observation results, the E.coli was cultured in a fermentor using the fed-batch method to determine the optimal production techniques.
  
  
  RESULTS
  Observation of the bacterium in the shaking flask showed initiation of the induction procedure in the mid-log growth phase at 25 degrees Celsius; with 0.2% arabinose resulted in the highest production of anti-HBsAg Fab. The D(600) value of the culture reached 55.2, equivalent to 110 g/L wet weight of the bacterium, using the DO-stat fed-batch method. The resultant Fab showed well-preserved biological activity.
  
  
  CONCLUSIONS
  Reliable techniques for rapid and massive production of the Fab have been developed.
authors.affiliation: Department of Oncology, Nanfang Hospital, First Military Medical University, Guangzhou 501515, China. zhengdayong@hotmail.com
authors.forename: Da-yong
authors.initials: DY
authors.lastname: Zheng
authors.forename: Rong-cheng
authors.initials: RC
authors.lastname: Luo
authors.forename: Hong-bin
authors.initials: HB
authors.lastname: Cai
mesh_terms: D004926:Escherichia coli / Q000235:genetics*; D005285:Fermentation; D005818:Genetic Engineering; D006510:Hepatitis B Antibodies / Q000096:biosynthesis*; D006514:Hepatitis B Surface Antigens / Q000276:immunology*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007140:Immunoglobulin Fab Fragments / Q000096:biosynthesis*
chemical_list: D006510:Hepatitis B Antibodies; D006514:Hepatitis B Surface Antigens; D007140:Immunoglobulin Fab Fragments