Screening Of High Yield γ-Aminobutyric Acid (GABA) Strains And Optimization Of Fermentation Conditions

y-aminobutyric acid (GABA) belongs to nonprotein amino acid and mainly distributes in plants and animals. With the deepening of the study, the physiological functions of GABA got popularly attention.GABA are widely used in medicine, health food, chemical industry and agriculture, etc.Use Lactobacillus plantarum Lb-17 as the starting strain.Study on mutation breeding,fermentation process and extraction technology.To establish fermentation dynamics model.(1)The original strain was mutagenesis treated with UV and chemical.Operation con ditions are as foliows:UV irradiation time 70s,diethyl sulfate(DES)volume fraction is 25. 0%,the processing time is 20min,achieving high yield mutant strains named an Lb-17-3 5.The production of GABA increased from 4.40g/L to 5.49g/L,is 1.25 times higher than starting strain.(2) Use Lactobacillus plantarum Lb-17 as the starting strain.The production of GA BA is index. Using single factor experiment and response surface experiment Box-Behn ken optimize the fermentation medium to get the optimal medium for:12.0g/L glucose,y east powder 18.0g/L, Ca2+55.0mmol/L,Mg2+60.0mmol/L,monosodium glutamate 26.0g/L.T he production of GABA is 8.037g/L,1.5 times higher than that of 5.49g/L before optimi zation.(3) GABA fermentation from Lactobacillus plantarum Lb-17 is second fermentation. Using MATLAB software to programming and nonlinear fitting planning with cftool too-lbox,and plant Lactobacillus Lactobacillus plantarum Lb-17 fermentation production of GABA fermentation kinetic model equation for:(1)the bacteria growth dynamics model:(4)The amount of glucose in the fermented liquid,the content of monosodium gluta mate,the bacteria biomass and GABA content is index.Using small fermentation tank to fill material research,the results showed:when the glucose content is about 2.0g/L,sodi um glutamate surplus is about 3.Og/L.Eventually the production of GABA is 20.84g/L,in-creased 1.36 times.(5) Fermentation Broth was treated with Ion- exchange purification.Freeze drying to obtain GABA products.The best Ion- exchange condition is:pH 5.5,flow rate of 2.0ml/ min,the sample liquid concentration is 6.0g/L,eluent concentration is 0.5mol/L.Under this condition,GABA purity up to 76.3%,extraction ratio is 83.0%.