Characterization of waste cell biomass derived glutamate decarboxylase for in vitro γ-aminobutyric acid production and value-addition

Waste biomass of Lactobacillus brevis obtained from in vivo gamma-aminobutyric acid (GABA) production was used for value-addition. This study aims to extract glutamate decarboxylase (GAD) and characterize it for in vitro GABA production. Extracted GAD showed an excellent activity for in vitro GABA production. 52 W ultrasonic output was best in crude GAD extraction which was purified by Q HP anion-exchange column followed by Superdex-200 colloid separation column. The molecular weight of the purified GAD was determined to be similar to 53 kDa, and the K-m value for L-glutamic acid was calculated similar to 7.65 mM. Pyridoxal 5'-phosphate (PLP) acted as the best cofactor for GAD. Optimum temperature and PLP dosing were deferring for crude and purified enzyme forms which respectively exhibited at 45 degrees C, 55 degrees C, 200 nmol and 20 mu mol whereas optimum pH was the same at 4.5. GAD finds applications in food industries hence its detailed characterization would be promising for commercial exploitations.

Automated summary

In this study, waste biomass from Lactobacillus brevis was used for in vitro GABA production by extracting and characterizing glutamate decarboxylase (GAD) with excellent activity. The purified GAD had a molecular weight of around 53 kDa and a KM value for L-glutamic acid of approximately 7.65 mM. Optimum temperature and cofactor dosage for GAD varied for crude and purified enzyme forms.