Enrichment of gamma-aminobutyric acid (GABA) in old antler extract fermented by Lactobacillus plantarum

녹각 추출액의 젖산발효를 통한 고농도 감마-아미노부티르산 생산 최적화

Optimization of the lactic acid fermentation process was carried out to produce an old antler extract fortified with ${\gamma}$-aminobutyric acid (GABA). An old antler extract (OAE; 5%, w/v) obtained using a herbal extractor showed the highest contents of solids (1.75%) and proteins ($980{\mu}g/mL$). It also showed the highest total amino acid contents of $13,659{\mu}g/mL$, with glycine, proline, and glutamine concentrations of 1,945, 3,405, and $1,641{\mu}g/mL$, respectively. For the over-production of GABA, OAE was fermented with Lactobacillus plantarum EJ2014 in the presence of 0.5%, 1.5% glucose, and 3.5% MSG at $30^{\circ}C$ for 7 days. The fermented OAE showed high viable cell count of $2.0{\times}10^8CFU/mL$, pH of 6.56 and 0.77% acidity after 7 days. In particular, the acidity was greatly decreased by fermentation for 3 days, and 1.4% GABA was produced by the efficient conversion of the substrate, mono sodium glutamate.

본 연구에서는 녹각 추출물을 이용하여 GABA 생산 최적화를 위해 추출액의 농도, 질소원인 YE, 탄소원 포도당, GABA 생성전구물질 MSG 농도에 따른 최적조건으로 YE 0.5%, 포도당 1.5%, MSG 3.5%를 첨가하여 $30^{\circ}C$에서 7일간 젖산발효를 하였다. 발효 7일 pH 6.56, 산도 0.77%로 나타났으며 $2.0{\times}10^8CFU/mL$로 높은 균수를 유지하였고 GABA를 1.4% 생성하는 것으로 나타났다. 결론적으로 녹각 추출액의 젖산균을 이용한 정치배양을 통해 고농도의 GABA 생산이 가능하였으며, 발효물은 GABA, 프로바이오틱(probiotic) 등을 함유하여 식품 및 기능성 소재로 이용가능성이 높다고 사료되었다.