HEBERT Elvira Maria
congresos y reuniones científicas
Optimization of fermentative parameters for γ-aminobutyric acid production by Lactobacillus brevis CRL 2013
Simposio; SIBAL 2016. V International Symposium on Lactic Acid Bacteria. Benefitting from Lactic Acid Bacteria. Progress in Health and Food.; 2016
Gamma-Aminobutyric acid (GABA), a major inhibitory neurotransmitter, is a non-protein aminoacid that is widely distributed in nature. GABA and GABA-rich foods have shown anti-hypertensive and antidepressant activities as the most remarkable functions in humans and animals. Hence, high GABA producing lactic acid bacteria (LAB) could be used as functional starters for manufacturing novel fermented foods. Previously, we screened several LAB belonging to the CERELA collection for GABA production. Lactobacillus (L.) brevis CRL 2013 was selected for further studies since it shown a high conversion rate (~94 %) with monosodic glutamate (MSG) used as substrate. The aim of this study was to optimize the culture conditions for enhancing GABA production by L. brevis CRL 2013. The GABA content, measured by an enzymatic assay (GABase), was evaluated for different MSG concentrations (0, 107, 267 and 364 mM), incubation temperatures (20-45 °C) and initial pHs from 4.0 to 7.25 using MRS as growth medium during 72 h of incubation time. A gradual increase in GABA production was observed when MSG concentration increased from 0 to 267 mM. However, GABA yield decreased for MSG concentrations above 267 mM. Under these conditions (267 mM MSG), the highest synthesis of GABA was obtained at 30 and 37 °C, reaching values of ~259 and 263 mM, respectively. Conversely, at 45 °C, the microorganism was not able to grow and GABA could not be detected. Respect to environmental pH influence, no significant differences in GABA yield were observed for pH values between 6.0-7.25, while GABA production sharply decreased for pH values below 6.0. In conclusion, the highest GABA yield produced by L. brevis CRL 2013 in MRS with 267 mM MSG, was achieved at 30 °C after 72 h of fermentation and an initial pH value of 6.5. The optimization of growth conditions for enhancing GABA production by L. brevis CRL 2013 is an important breakthrough for the development of health promoting foods.