Establishment of an Efficient Fermentation System of Gamma-Aminobutyric Acid by a Lactic Acid Bacterium, Enterococcus avium G-15, Isolated from Carrot Leaves

Tamura Takayoshi

Noda Masafumi

Ozaki Moeko

Maruyama Masafumi

Matoba Yasuyuki

Kumagai Takanori

Sugiyama Masanori

Biological and Pharmaceutical Bulletin

In the present study, we successfully isolated a carrot leaf-derived lactic acid bacterium that produces gamma-aminobutyric acid (GABA) from monosodium L-glutamate (L-MSG) at a hyper conversion rate. The GABA-producing bacterium, identified as Enterococcus (E.) avium G-15, produced 115.7±6.4 g/l GABA at a conversion rate of 86.0±5.0% from the added L-MSG under the optimum culture condition by a continuous L-MSG feeding method using a jar-fermentor, suggesting that the bacterium displays a great potential ability for the commercial-level fermentation production of GABA. Using the reverse transcription polymerase chain reaction (RT-PCR) method, we analyzed the expression of genes for the GABA transporter and glutamate decarboxylase, designated gadT and gadG, respectively, which were cloned from the E. avium G-15 chromosome. Both genes were expressed even without the added L-MSG, but their expression was enhanced by the addition of L-MSG.

plant-derived lactic acid bacteria

Enterococcus avium

gamma-aminobutyric acid

Medical sciences [ 490 ]

eng

The Pharmaceutical Society of Japan

© 2010 Pharmaceutical Society of Japan

[ISSN] 0918-6158

[ISSN] 1347-5215

[NCID] AA10885497

[DOI] 10.1248/bpb.33.1673

[DOI] https://doi.org/10.1248/bpb.33.1673