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Formate accumulation due to DNA release in aerobic cultivations of Escherichia coli
Author(s) -
Castan Andreas,
Enfors SvenOlof
Publication year - 2001
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.1198
Subject(s) - formate , dna , mixed acid fermentation , escherichia coli , chemistry , biochemistry , fermentation , sodium formate , recombinant dna , bacteria , biology , inorganic chemistry , lactic acid , gene , lactic acid fermentation , genetics , catalysis
Three different aerobic fed‐batch processes of Escherichia coli were studied, two for the production of a recombinant protein and one process with a wild‐type E. coli strain. In all three processes, an accumulation of formate could be observed in the latter part of the process. Analysis of the concentration of DNA in the medium revealed that the release of DNA coincided with the accumulation of formate. It was found that increasing concentrations of DNA correlated in almost linearly increasing concentrations of formate. Formate accumulation is caused by mixed acid fermentation, although no oxygen limitation was measured with the DO electrode. It is proposed that extracellular DNA restrained mass transfer between the bulk medium and the cell. To investigate if the DNA accumulation caused formate production, DNA was removed by continuous feeding of a DNA binding polymer to the medium. The addition of the polymer decreased the content of free DNA in the broth and the formate was reassimilated. Furthermore, additional DNA early in the process resulted in early formate accumulation. © 2002 John Wiley & Sons, Inc. Biotechnol Bioeng 77: 324–328, 2002.