Novel bioconversion of sodium glutamate to γ-amino butyric acid by co-culture of Lactobacillus plantarum K154 in Ceriporia lacerata culture broth

Co-cultivation was performed for optimization of microbial GABA production in Ceriporia lacerata cultures. C. lacerata was grown in a defined medium containing 3% glucose, 3% soybean flour, 0.15% MgSO4, and 5% rice bran for 7 days at 25°C in a shaking culture, resulting in production of a culture with 0.63% (w/v) acidity, 11.2 g/L of mycelia, 3.0 g/L of exopolysaccharides, 6.24 unit/mL of α-amylase, 45.6 unit/mL of protease and 4.1 unit/mL of cellulase. Viable cell counts of Lactobacillus plantarum K154 co-cultured in C. lacerata culture broth were increased by 1×1010 CFU/mL. In co-cultivation with L. plantarum K154, 15.53 mg/mL of GABA was produced from sodium glutamate. A 40 kDa molecular weight protein co-produced with GABA by L. plantarum K154 was confirmed to be GAPDH based on protein sequencing. Co-cultivation of L. plantarum K154 in C. lacerata culture broth efficiently produced functional ingredients, including GABA, peptides, polysaccharides, and probiotics.