Research On The Concentration Of GABA In Wastewater Of Tofu

y-aminobutyric acid (gamma aminobutyric acid, GABA) is a kind is of natural amino acids which exist in the mammalian central nervous system (CNS) of an inhibitory neurotransmitter. GABA has much attention from the researchers, because of many effect. For instance, the effect for anti-anxiety, sedative, treatment of epilepsy, anti-aging effect and so on.wastewater of tofu as the by-products of tofu.With the yield increasing,the processing of wastewater of tofu problem is attracting more and more attention. Wastewater of tofu rich nutrients and inorganic salt, also contain a certain amount of GABA. On the basis of wastewater of tofu enrichment of nutrient components and optimize, the fermentation conditions to high concentration of GABA.Lactic acid bacteria was studied in wastewater of tofu to enrichment of GABA fermentation conditions, the extraction and purification of GABA and the technological process. For example: high GABA lactic acid bacteria screening-enrichment GABA of wastewater of tofu-lacto bacillus bacteria remove-different methods of fermented liquid decoloring treatment (activated carbon and macroporous adsorption resin)-ion exchange of GABA-GABA crystallization-the determination of content of GABA,and the various steps into the study of concrete. Main conclusions are as follows:(1) The wastewater of tofu medium components were optimized through the water, it was concluded that Lactobacillus bulgaricus1.0205producted GABA conditions for the optimal medium:glucose2%, peptone2%,(NH4)2SO41%, KH2PO40.08%. Through to wastewater of tofu the culture medium initial pH value and research, the amount of sodium glutamate added to determine the initial pH is7.0, monosodium glutamate content is3%. Fermentation of Lactobacillus bulgaricusl.0205dynamic research showed that the biomass in the fermentation process, protein content, pH value and the change of content of GABA, further illustrate Lactobacillus bulgaricus1.0205growth situation and GABA production characteristics, determine the best fermentation time is40h, at this point in the fermented liquid biomass (OD600) is1.63, GABA can reach6.22g/L.(2) Based on chitosan flocculant flocculation of single factor, the experiment was carried out, the optimal dosage of chitosan is1%, polyaluminium chloride adding amount was4%, the optimum temperature at room temperature, pH value of4.5and slow mixing time for20min. Followed by response surface experiment, found in polymerization aluminum chloride3.8%, pH4.7, slowed mixing time20min for the final conditions, three parallel tests have been the real flat turbidity lower than98.27%, while the loss rate of GABA only about3%.(3) The activated carbon-ultrasonic joint processing was shown that in the activated carbon-ultrasonic joint processing, pigment removal rate is higher, GABA loss also increased slightly. Second single factor experiments, found in activated carbon particle size of40mesh, amount of activated carbon is4%, the temperature of the fermented liquid is50℃, the ultrasonic power is120w, ultrasonic time is40min, the stirring speed is70r/min, the amount of pigment removal is higher. Finally adopted four factors three levels orthogonal experiment, showed that activated carbon dosage was5%,50min ultrasonic time, ultrasonic power120w, activated carbon particle size50mu, decoloring rate78.68%, the GABA loss rate was36.87%.(4) Under the decolorization of5kinds of macroporous resin for screening, found that the macroporous adsorption resin D101has the high decolorization rate and the rate of GABA. Hole adsorption resin D101static adsorption experiment was carried out to determine the dosage of resin which is1.5g/ml,20fermented liquid pH value is5, temperature is20-30℃. Through dynamic adsorption experiment to investigate the influence of velocity on decoloring, results showed that the macroporous adsorption resin D101deal with the optimum fermented liquid flow velocity is3BV/h, capacity is5BV, this time the total decolorization rate can reach93.2%, this stage GABA recovery was86%. Eluent again use has great influence of resin, the single factor experiment, showed that80%ethanol concentration, pH value of7and elution rate of5BV/h, resolution of pigment can reach above90%.(5) Using5kinds of ion exchange to resin filter, Discovery of D001ion exchange resin has advantages of exchange capacity. D001ion resin static ion exchange experiments show that the ion exchange experiments, the effects of pH value is decline, the pH value is6, the largest amount is144.7mg/g. Ion exchange time is80min, the temperature is at room temperature. Dynamic ion exchange shows that2BV/h sample volume on the sample, the sample weight is4.5BV. Eluent to elution ion exchange resin on the GABA, ammonia concentration is2mol/L, collection of eluent volume is2BV.(6) The crystallization method to get the GABA products,GABA yield is about48.9%, identification of purity by HPLC, the purity of the GABA reached more than95%.