Vital parameters for high gamma-aminobutyric acid (GABA) production by an industrial soy sauce koji aspergillus oryzae NSK in submerged-liquid fermentation

• Main Authors: Wan-Mohtar, Wan Abd Al Qadr Imad, Ab Kadir, Safuan, Abdul Halim Lim, Sarina, Ilham, Zul, Azhari, Siti Hajar, Saari, Nazamid
• Format: Article
• Language: English
• Published: Korean Society of Food Science and Technology 2019
• Online Access: http://psasir.upm.edu.my/id/eprint/82728/1/Vital%20parameters%20for%20high%20gamma-aminobutyric%20acid%20.pdf; http://psasir.upm.edu.my/id/eprint/82728/; https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6859140/
• Institution: Universiti Putra Malaysia

In submerged-liquid fermentation, seven key parameters were assessed using one-factor-at-a-time to obtain the highest GABA yield using an industrial soy sauce koji Aspergillus oryzae strain NSK (AOSNSK). AOSNSK generated maximum GABA at 30 °C (194 mg/L) and initial pH 5 (231 mg/L), thus was able to utilize sucrose (327 mg/L of GABA) for carbon source. Sucrose at 100 g/L, improved GABA production at 646 mg/L. Single nitrogen sources failed to improve GABA production, however a combination of yeast extract (YE) and glutamic acid (GA) improved GABA at 646.78 mg/L. Carbon-to-nitrogen ratio (C8:N3) produced the highest cell (24.01 g/L) and GABA at a minimal time of 216 h. The key parameters of 30 °C, initial pH 5, 100 g/L of sucrose, combination YE and GA, and C8:N3 generated the highest GABA (3278.31 mg/L) in a koji fermentation. AOSNSK promisingly showed for the development of a new GABA-rich soy sauce.