Fundamental Study on Production of γ-Aminobutyric Acid using Rice-bran Extract

Production of γ-aminobutyric acid (GABA) was investigated using rice-bran extract for effective utilization of agricultural resources. In the experiments using L-glutamic acid as substrate and rice bran extract as an additive including enzyme, the GABA production reaction stoichiometrically proceeded. The optimum conditions of pH and temperature for GABA production were at pH 5.5 and 30~40°C. The kinetic parameters of rice-bran extract using L-glutamic acid as a substrate were also evaluated by a mathematical model that considered the material balances of L-glutamic acid and GABA, and reaction rate expressed by Michaelis-Menten’s equation. The model successfully explained the concentration profiles of experimental data.