Abstract Background ℽ-Aminobutyric acid (GABA) is a non-proteinaceous amino acid. In the mammalian nervous system, GABA functions as an inhibitory neurotransmitter. The present study focused on screening and optimization of ℽ-aminobutyric yield by lactic bacteria using soymilk basal media. Lactobacillus fermentum ( Lb. ) was isolated from sourdough. qualitative confirmation production observed ...