The incubation temperature is also a major factor affecting
maximum GABA yield by fermentation. In addition to an
effect on biocatalyst activity and stability, temperature has an
effect on the thermodynamic equilibrium of a reaction. The
high efficient conversion of glutamate to GABA needs the high
cell density and also the appropriate culture temperature (38).
GABA production in Lb. brevisNCL912 had a positive
correlation with the cell density, which was dependent on the
culture temperature (49). Lb. brevisNCL912 growth increased
with higher temperature and peaked at 35°C, then decreased
over the temperature (49). Cultured Lb. plantarumDSM19463
synthesized the highest amount of GABA (59 μM/h) at
temperatures between 30°C and 35°C (17). The optimum
temperatures for Lb. brevisGAD and Lb. brevisCGMCC 1306
were found to be as 30°C and 37°C, respectively (85, 86). Lb.
brevisGABA 100 fermenting black raspberry juice produced
maximum GABA (27.6 mg/ml) at pH 3.5 and 30°C on 12 th
day of fermentation (38).Lb. buchneriin MRS broth medium also
had the optimum temperature for GABA production as 30°C
(12). Immobilized whole cells of Lb. brevisat 40°C produced
92% of GABA after 8 h of fermentation (30). The maximum
GABA yields by Lc. lactis at the optimum temperature of 33°C