title: Fed-batch cultivation of Bordetella pertussis: metabolism and Pertussis Toxin production.
abstract: The production of acellular pertussis in comparison with whole cell pertussis vaccines demands 5-25 times the amount of Bordetella pertussis' virulence factors, such as Pertussis Toxin (PT), to produce the same number of vaccine doses. An increase in the volumetric productivity by employing fed-batch rather than the currently used batch cultivations of B. pertussis could reduce the cost price of acellular pertussis vaccines. This study defined the conditions that enable fed-batch cultivations at high specific PT production. A solution containing lactate and glutamate was fed to the cultures at various rates. The feed rate and whether or not the fed substrates were completely consumed, significantly influenced cellular metabolism. If lactate was detectable in the culture broth while glutamate was not, poly-hydroxy-butyrate (PHB) was formed. Any PHB present was metabolized when glutamate became detectable again in the culture liquid. At higher lactate and glutamate concentrations, free fatty acids were produced. Though toxic, free fatty acids were not the reason the cultures stopped growing. By choosing appropriate conditions, a cell density of 6.5 g/L dry weight was reached, i.e. a 7-fold increase compared to batch culture. The metabolic mechanisms behind the formation of PHB and fatty acids are discussed, as well as how to increase the cell density further. The PT production stopped at 12 mg/L, well before growth stopped, indicating that regulatory mechanisms of PT production may be involved.
authors.affiliation: SynCo Bio-Partners, Paasheuvelweg 30, 1105 BJ Amsterdam ZO, The Netherlands. marcel_thalen@synco-biopartners.com
authors.forename: Marcel
authors.initials: M
authors.lastname: Thalen
authors.forename: Marian
authors.initials: M
authors.lastname: Venema
authors.forename: Anita
authors.initials: A
authors.lastname: Dekker
authors.forename: Luc
authors.initials: L
authors.lastname: Berwald
authors.forename: Jan
authors.initials: J
authors.lastname: van den IJssel
authors.forename: Bert
authors.initials: B
authors.lastname: Zomer
authors.forename: Coen
authors.initials: C
authors.lastname: Beuvery
authors.forename: Dirk
authors.initials: D
authors.lastname: Martens
authors.forename: Johannes
authors.initials: J
authors.lastname: Tramper
mesh_terms: D001431:Bacteriological Techniques; D001886:Bordetella pertussis / Q000254:growth & development* / Q000378:metabolism*; D008954:Models, Biological; D010084:Oxidation-Reduction; D037342:Pertussis Toxin / Q000096:biosynthesis*
chemical_list: D037342:Pertussis Toxin