Preparation of γ-aminobutyric acid using E-coli cells with high activity of glutamate decarboxylase

gamma-Aminobutyric acid (GABA) is a major inhibitory neurotransmitter synthesized in the central nervous system from glutamate by glutamate decarboxylase (GAD). It has applications in the production of many drugs. The technology of GABA synthesis by treating L-glutamic acid with the cells of the gene-engineered GAD superproducer strain of Escherichia coli GADK10 was developed. Cell growing in the presence of 0.02 mM pyridoxal phosphate (PLP) causes the 2- to 2.5-fold increase of total productivity of the cells. The best way to prep are the cells for the reaction was their thermal activation by pretreatment for 1 h at 53 degrees C. The optimal conditions for this reaction were 37 degrees C and pH 4.6. The rate of the enzymatic reaction is the function of acetate concentration with the maximum at 0.5 M acetate. The total amount of GABA synthesized using 1 g of wet cells reached 23-25 g. The final concentration of GABA in the reaction medium was 280-300 g/L. The yield of the product was about 99%.