title: Enhanced Production of Gamma-Aminobutyric Acid by Optimizing Culture Conditions ofLactobacillus brevisHYE1 Isolated from Kimchi, a Korean Fermented Food.
abstract: This study evaluated the effects of culture conditions, including carbon and nitrogen sources, L-monosodium glutamate (MSG), and initial pH, on gamma-aminobutyric acid (GABA) production byLactobacillus brevisHYE1 isolated from kimchi, a Korean traditional fermented food.L. brevisHYE1 was screened by the production analysis of GABA and genetic analysis of the glutamate decarboxylase gene, resulting in 14.64 mM GABA after 48 h of cultivation in MRS medium containing 1% (w/v) MSG. In order to increase GABA production byL. brevisHYE1, the effects of carbon and nitrogen sources on GABA production were preliminarily investigated via one-factor-at-a-time optimization strategy. As the results, 2% maltose and 3% tryptone were determined to produce 17.93 mM GABA in modified MRS medium with 1% (w/v) MSG. In addition, the optimal MSG concentration and initial pH were determined to be 1% and 5.0, respectively, resulting in production of 18.97 mM GABA. Thereafter, response surface methodology (RSM) was applied to determine the optimal conditions of the above four factors. The results indicate that pH was the most significant factor for GABA production. The optimal culture conditions for maximum GABA production were also determined to be 2.14% (w/v) maltose, 4.01% (w/v) tryptone, 2.38% (w/v) MSG, and an initial pH of 4.74. In these conditions, GABA production byL. brevisHYE1 was predicted to be 21.44 mM using the RSM model. The experiment was performed under these optimized conditions, resulting in GABA production of 18.76 mM. These results show that the predicted and experimental values of GABA production are in good agreement.
authors.affiliation: Department of Life Sciences, Graduate School of Incheon National University, Incheon 22012, Republic of Korea.
authors.forename: Hee Seon
authors.initials: HS
authors.lastname: Lim
authors.affiliation: Division of Bioengineering, Incheon National University, Incheon 22012, Republic of Korea.
authors.forename: In-Tae
authors.initials: IT
authors.lastname: Cha
authors.affiliation: Biological Disaster Analysis Group, Korea Basic Science Institute, Daejeon 34133, Republic of Korea.
authors.forename: Seong Woon
authors.initials: SW
authors.lastname: Roh
authors.affiliation: Division of Foodservice Industry, Baekseok Culture University, Chungnam 31065, Republic of Korea.
authors.forename: Hae-Hun
authors.initials: HH
authors.lastname: Shin
authors.affiliation: Department of Life Sciences, Graduate School of Incheon National University, Incheon 22012, Republic of Korea.|Division of Bioengineering, Incheon National University, Incheon 22012, Republic of Korea.
authors.forename: Myung-Ji
authors.initials: MJ
authors.lastname: Seo
mesh_terms: D050260:Carbohydrate Metabolism; D005285:Fermentation; D005516:Food Microbiology; D008401:Gas Chromatography-Mass Spectrometry; D006863:Hydrogen-Ion Concentration; D052196:Levilactobacillus brevis / Q000145:classification / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D055432:Metabolomics / Q000379:methods; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D005680:gamma-Aminobutyric Acid / Q000096:biosynthesis* / Q000737:chemistry
chemical_list: D012336:RNA, Ribosomal, 16S; D005680:gamma-Aminobutyric Acid
keywords: Gamma-aminobutyric acid; Lactobacillus brevis; fermented food; optimization; response surface methodology