Biotechnology Letters, Vol.26, No.16, 1301-1306, 2004
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) 1(-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 theological 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) 1(-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).