Robust production of gamma-amino butyric acid using recombinant Corynebacterium glutamicum expressing glutamate decarboxylase from Escherichia coli

• Published in: Enzyme and microbial technology 2012-08, Vol.51 (3), p.171-176
• Main Authors: Takahashi, Chihiro, Shirakawa, Junki, Tsuchidate, Takeyuki, Okai, Naoko, Hatada, Kazuki, Nakayama, Hideki, Tateno, Toshihiro, Ogino, Chiaki, Kondo, Akihiko
• Format: Article
• Language: English
• Subjects: biodegradability; Biotechnology - methods; carbon; Corynebacterium glutamicum; Corynebacterium glutamicum - enzymology; Corynebacterium glutamicum - genetics; Culture Media; drugs; Escherichia coli; Escherichia coli - metabolism; Fermentation; functional foods; Gamma-amino butyric acid; gamma-aminobutyric acid; gamma-Aminobutyric Acid - biosynthesis; genes; Genetic Engineering; glucose; Glutamate decarboxylase; Glutamate Decarboxylase - genetics; Glutamate Decarboxylase - metabolism; glutamic acid; high performance liquid chromatography; polyamides; pyridoxal; pyridoxal 5′-phosphate; Pyridoxal Phosphate - metabolism; Recombinant Proteins - genetics; Recombinant Proteins - metabolism
• ISSN: 0141-0229; 1879-0909
• DOI: 10.1016/j.enzmictec.2012.05.010

► GABA was produced directly from glucose by C. glutamicum expressing E. coli GadB. ► Without added glutamate, GABA productivity reached 12.3g/L in culture supernatant. ► Addition of PLP to the medium was found to enhance the production of GABA. ► By using C. glutamicum GAD, GABA was produced in a maximum yield of 0.17g/L/h. Gamma-amino butyric acid (GABA) is a component of pharmaceuticals, functional foods, and the biodegradable plastic polyamide 4. Here, we report a simple and robust system to produce GABA from glucose using the recombinant Corynebacterium glutamicum strain GAD, which expresses GadB, a glutamate decarboxylase encoded by the gadB gene of Escherichia coli W3110. As confirmed by HPLC analysis, GABA fermentation by C. glutamicum GAD cultured at 30°C in GABA Production 1 (GP1) medium containing 50g/L glucose without the addition of glutamate yielded 8.07±1.53g/L extracellular GABA after 96h. Addition of 0.1mM pyridoxal 5′-phosphate (PLP) was found to enhance the production of GABA, whereas Tween 40 was unnecessary for GABA fermentation. Using the optimized GABA Production 2 (GP2) medium, which contained 50g/L glucose and 0.1mM PLP, fermentation was performed in a flask at 30°C with 10% (v/v) seed culture of C. glutamicum GAD. GABA was produced in the culture supernatant with a yield of 12.37±0.88g/L after 72h with a space–time yield of 0.172g/L/h, which is the highest yield obtained to date for GABA from fermentation with glucose as a main carbon source.