Improved process for exopolysaccharide production by Klebsiella pneumoniae sp. pneumoniae by a fed-batch strategy.
Exopolysaccharide (EPS) was produced by Klebsiella pneumoniae K63 grown in fed-batch cultures using different procedures of the supply of carbon or nitrogen (N) source, or both. Cultures grown with excess of glucose and limitation or exhaustion of N produced 54.8 and 47.4 g(EPS) l(-1), respectively. These cultures also led to an accumulation of 'overflow' metabolites representing more than 16% of carbon conversion. The consistency indexes ( K ) obtained to the end of the cultures, characteristic of the rheological property of the biopolymer, were 16.4 Pa s(n) for N deficiency and 5.2 Pa s(n) for N limitation conditions. The simultaneous limitation of glucose and N decreased the excretion of co-metabolites (6.4% of carbon conversion) and the EPS production (18.1 g(EPS) l(-1)), while improving the quality of the polysaccharide, characterized by the highest K of 126.2 Pa s(n) and the highest pseudoplasticity degree (flow behaviour index, n=0.2).
Ramírez-Castillo
M L
ML
Centre de Bioingénierie Gilbert Durand, UMR-CNRS 5504 UR-INRA 792, Institut National des Sciences Appliquées, Département Génie Biochimique et Alimentaire, Complexe Scientifique de Rangueil, 31077 Toulouse Cedex, France.
Uribelarrea
J L
JL
D018929:Cell Culture Techniques / Q000379:methods*; D049109:Cell Proliferation; D003470:Culture Media / Q000737:chemistry / Q000378:metabolism; D005947:Glucose / Q000378:metabolism*; D007711:Klebsiella pneumoniae / Q000254:growth & development* / Q000378:metabolism*; D009584:Nitrogen / Q000378:metabolism*; D011135:Polysaccharides, Bacterial / Q000096:biosynthesis* / Q000737:chemistry; D014783:Viscosity
D003470:Culture Media; D011135:Polysaccharides, Bacterial; D005947:Glucose; D009584:Nitrogen