Gamma-Aminobutyric Acid Production Using Immobilized Glutamate Decarboxylase Followed by Downstream Processing with Cation Exchange Chromatography

International Journal of Molecular Sciences

Seungwoon Lee¹  Jungoh Ahn²  Yeon-Gu Kim²  Joon-Ki Jung²  Hongweon Lee² 

[1] University of Science and Technology (UST), 217 Gajeong-ro, Yuseong-gu, Daejeon 305-350, Korea; E-Mail:;Biotechnology Process Engineering Center, KRIBB, 125 Gwahak-ro Yuseong-gu, Daejeon 305-806, Korea; E-Mails:

关键词: gamma aminobutyric acid;    glutamate decarboxylase;    glutamic acid;    immobilization;    cation exchange chromatography;   

DOI  :  10.3390/ijms14011728

来源: mdpi

【 摘 要 】

We have developed a gamma-aminobutyric acid (GABA) production technique using his-tag mediated immobilization of Escherichia coli-derived glutamate decarboxylase (GAD), an enzyme that catalyzes the conversion of glutamate to GABA. The GAD was obtained at 1.43 g/L from GAD-overexpressed E. coli fermentation and consisted of 59.7% monomer, 29.2% dimer and 2.3% tetramer with a 97.6% soluble form of the total GAD. The harvested GAD was immobilized to metal affinity gel with an immobilization yield of 92%. Based on an investigation of specific enzyme activity and reaction characteristics, glutamic acid (GA) was chosen over monosodium glutamate (MSG) as a substrate for immobilized GAD, resulting in conversion of 2.17 M GABA in a 1 L reactor within 100 min. The immobilized enzymes retained 58.1% of their initial activities after ten consecutive uses. By using cation exchange chromatography followed by enzymatic conversion, GABA was separated from the residual substrate and leached GAD. As a consequence, the glutamic acid was mostly removed with no detectable GAD, while 91.2% of GABA was yielded in the purification step.

【 授权许可】

CC BY   
© 2013 by the authors; licensee Molecular Diversity Preservation International, Basel, Switzerland.