Screening Of Lactic Acid Bacteria That Is γ- Aminobutyricacid High Yieldand Study On Mixed Culture Fermentation Of Monascus And Lab

γ-Aminobutyric acid (GABA, CAS NO.: 56-12-2, molecular formula: C₄H₉NO₂, molecular mass: 103.12, fusion point: 197-204℃), which is a kind of natural active ingredients and widely distributed. It is an efficient inhibitory neurotransmitter in mammal. GABA has several physiological functions such as hypotensive activity, treatment of epilepsy, tranquilizing and allaying excitement, enhancing memory, controlling asthma, regulating hormone secretion, promoting reproduction and activating liver and kidney function. Preparation and application of GABA are concerned. Has been gradually applied in many industries such food and medicine.This study find a metiod which could measure the concentration of GABA efficiently and exactly, that is the OPA-HPLC method which using OPA as the derivating agent and ultraviolet detector in the wavelength of 335nm, the results show great effect and accrracy. This study also screens Lactic acid bacteria that with high production of GABA from fermented glutinous rice, yoghourt and some other traditional Chinese food. The result of identifying indicates that the LAB is Lactobacillus planetarium and is named Lac.1 by the author. Using the single factor test and orthogonal experimental design to optimize the culture medium and the results show that under the condition of 30℃, pH 6.0⁶.5, the components of medium are peptone 7.5g/l(0.75%), yeast extract 7.5g/l(0.75%), glucose 22.5g/l (2.25%), sodium succinic 7.5g/l(0.75%), L-Monosodium Glutamate (L-MSG) 1.5g/l, Vb6 0.2g/l, the production of GABA will be extended to 1.823g/l which is 6.24 times more than the initial.Results of the study on mixed culture fermentation of Monascus and Lac.1 indicate that they have efficient interaction with each other which help to increase the production of GABA, but the Monascus will grow slowly in where there are full of Lac.1, so we should inoculate them in different time. Results show that either live or dead mycelium of SM048, even the supernate of SM048 will increase the production of GABA, while the live mycelium do the best. In the condition of 50ml medium per 250ml triangular flask, pH 4-4.5, 30℃, adding 2g of live mycelium of SM 048 will increase the production of GABA efficiently, the concentration of GABA will be improved by 62.5%.