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Metabolic flux modeling of detoxification of acetic acid by Ralstonia eutropha at slightly alkaline pH levels
Author(s) -
Yu Jian,
Wang Jianping
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.1080
Subject(s) - ralstonia , acetic acid , chemistry , acidogenesis , polyhydroxyalkanoates , fermentation , detoxification (alternative medicine) , biochemistry , organic acid , chromatography , nuclear chemistry , food science , bacteria , organic chemistry , anaerobic digestion , enzyme , biology , medicine , alternative medicine , pathology , methane , genetics
Ralstonia eutropha grows on and produces polyhydroxyalkanoates (PHAs) from fermentation acids. Acetic acid, one major organic acid from acidogenesis of organic wastes, has an inhibitory effect on the bacterium at slightly alkaline pH (6 g HAc/L at pH 8). The tolerance of R. eutropha to acetate, however, was increased significantly up to 15 g/L at the slightly alkaline pH level with high cell mass concentration. A metabolic cell model with five fluxes is proposed to depict the detoxification mechanism including mass transfer and acetyl‐CoA formation of acetic acid and the formation of three final metabolic products, polyhydroxybutyrate (PHB), active biomass, and CO 2 . The fluxes were measured under different conditions such as cell mass concentration, acetic acid concentration, and medium composition. The experimental results indicate that the acetate detoxification by high cell mass concentration is attributed to the increased fluxes at high extracellular acetate concentrations. The fluxes could be doubled to reduce and hence detoxify the accumulated intracellular acetate anions. © 2001 John Wiley & Sons, Inc. Biotechnol Bioeng 73: 458–464, 2001.