Optimization of nutrient medium for Pediococcus acidilactici DS15 to produce GABA

Abstract

Nutrition is an essential factor for microorganisms to grow and survive. Carbon and nitrogen sources are used in producing primary and secondary metabolites. Gamma-Aminobutyric acid (GABA), a non-coded amino acid, is a secondary metabolite which acts as an inhibitory neurotransmitter of the central nervous system. Pediococcus acidilactici DS15 is a bacterium belonging to the order of Lactic Acid Bacteria. This study aimed to determine the effects of nutrients including glutamate, nitrogen and carbon sources on GABA production by Pediococcus acidilactici DS15. The tests were carried out using a range of 30 mM, 40 mM, 50 mM, 60 mM, and 70 mM glutamate as inducer and carbon sources in the form of peptone, yeast extract, skim milk, NH4NO3, KNO3, whey tofu and soy milk as nitrogen sources, and then glucose, lactose, maltosa, sucrose, palm, and cane sugar as carbon sources. The best sources of both will be tested with levels 10, 20, 30, 40, 50, 60, 70, 80, 90 and 100% for nitrogen and 1, 3, 5, 7, 9, 11, 13 and 15% for carbon. The results of this investigation revealed that the addition of 60 mM glutamate caused the higher amount of GABA production and the best source of nitrogen and carbon for Pediococcus acidilactici DS15 were 100% whey tofu and 15% palm sugar, respectively. Production rate of GABA by Pediococcus acidilactici DS15 could reach up to 311,485 mg / L.