Establishment of an Efficient Fermentation System of Gamma-Aminobutyric Acid by a Lactic Acid Bacterium, Enterococcus avium G-15, Isolated from Carrot Leaves
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Matoba, Yasuyuki 大学院医歯薬保健学研究科（薬）
plant-derived lactic acid bacteria
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.
This work was supported by Hiroshima Biocluster (a Cooperative Link of Unique Science and Technology for Economy Revitalization), Japan (M.S.).
Biological and Pharmaceutical Bulletin
The Pharmaceutical Society of Japan
© 2010 Pharmaceutical Society of Japan