peptones and magnesium-carbonate

The effect of process optimization on succinic acid production by Escherichia coli W3110 and on enzymes involved in the reverse tricarboxylic acid cycle was studied. Approximately, 7.02 g L-1 of succinic acid was produced in 60 h at pH 7.0 in 500 mL anaerobic bottles containing 300 mL of the medium, wherein the sucrose concentration was 2.5%, the ratio of tryptone to ammonium hydrogen phosphate was 1:1, and the concentration of magnesium carbon ate was 1.5%. When these optimized fermentation conditions were employed in a 10 L bioreactor, 11.2 g L-1 of succinic acid was produced in 48 h. This is a 10-fold increase in succinic acid production from the initial titer of 0.94 g L-1. This clearly indicates the importance of process optimization, where by manipulating the media composition and production conditions, a remarkable increase in the production of the desired biomolecule can be obtained. The production of succinic acid is a multi-step reaction through the reverse tricarboxylic acid cycle. A linear relationship was observed between succinic acid production and the enzyme activities. The enzyme activities were found to increase in the order phospho-enol-pyruvate carboxylase

Topics: Anaerobiosis; Bioreactors; Citric Acid Cycle; Escherichia coli; Fermentation; Hydrogen-Ion Concentration; Industrial Microbiology; Ions; Magnesium; Peptones; Phosphates; Phosphoenolpyruvate Carboxylase; Succinic Acid; Sucrose; Temperature