title: Features of bacterial growth and polysaccharide production of Streptococcus pneumoniae serotype 14.
abstract: The effect of several cultivation conditions on the kinetics of bacterial growth and polysaccharide production of Streptococcus pneumoniae serotype 14 was studied. The presence in the supernatant of serotype-specific CPS (capsular polysaccharide) during growth was followed by size-exclusion HPLC and, in parallel, confirmed by using a specific latex reagent. The agitation level did not affect the production behaviour, whereas pH maintenance above 6 strongly enhanced both growth and CPS production throughout the cultivation period in flasks. Production of high-molecular-mass polysaccharide was found to be maximal between 5 and 6 h of cultivation, at the end of the exponential phase. By laser light scattering, 90% of this purified CPS product showed a M(w) (molecular mass) range from 350 to 1500 kDa, with an average M(w) of 921 kDa. Extending the culture to 24 h gave rise to a clear shift of the M(w) distribution of the polysaccharide to values lower than 100 kDa. These findings may have strong implications for the large-scale manufacture of the polysaccharide and the associated conjugate vaccine.
authors.affiliation: Departamento de Desarrollo Biotecnológico y Producción, Instituto de Higiene, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay. massaldi@higiene.edu.uy
authors.forename: Hugo
authors.initials: H
authors.lastname: Massaldi
authors.forename: M Inés
authors.initials: MI
authors.lastname: Bessio
authors.forename: Norma
authors.initials: N
authors.lastname: Suárez
authors.forename: Esther
authors.initials: E
authors.lastname: Texeira
authors.forename: Silvina
authors.initials: S
authors.lastname: Rossi
authors.forename: Fernando
authors.initials: F
authors.lastname: Ferreira
mesh_terms: D016667:Bacterial Capsules / Q000378:metabolism*; D011135:Polysaccharides, Bacterial / Q000378:metabolism*; D012703:Serotyping; D013296:Streptococcus pneumoniae / Q000145:classification / Q000254:growth & development* / Q000378:metabolism*; D013997:Time Factors
chemical_list: D011135:Polysaccharides, Bacterial