Research γ- Amino Butyric Acid Produced Alginate-embedded Acidilactici

Pediococcus acidilacticii is a kind of probiotics which is benefical to human body,it’s metabolic process can produce metabolites such as GABA, Pediococcusacidilacticii ivermectin, which has obviously function in promoting bodily function andphysiological function.Among those, GABA has the function of reducing blood press, calming the nerves,anti-aging, treating epilepsy, promoting reproductive and so on. The main productionmethod of GABA is microbial fermentation, this method is safe, fast and the outcome iseasy to extract. Use calcium alginate embedding the Pediococcus acidilacticii toimmobilized fermentation can shorten the fermentation period, increase logarithmicphase, stockpile a large quantity of metabolites and the metabolites are easier toseparate.Observe the microstructure of immobilized cell, explore the mass transferperformance of calcium alginate cyst and the maxium MWCO of the cyst membrane.Immobilized culture the microorganism, study the BC of calcium alginate gel bead cystand Pediococcus acidilacticii cell, the influences medium components have to themechanical strength of calcium alginate cyst, and the continuous culture of theimmobilized Pediococcus acidilacticii. And finally, study the fermentation kinetics of theimmobilized Pediococcus acidilacticii.Firstly, immobilize the Pediococcus acidilacticii under the best embeddingcondition, observe the microstructure of the cyst through SEM, the average aperture onthe inner surface of Pediococcus acidilacticii cyst is around366nm，on the outer surfaceis around162nm. And the average diameter of the thallus is around707nm, so thethallus can be immobilized in the cyst quite well, won’t leak easily. Study themicromolecure nutrient’s mass transfer ability of getting into Pediococcus acidilacticiicyst：glucose, lactose, L-phenylalanine, glutamic acid. The result comes out that all of them can get into Pediococcus acidilacticii cyst quite quickly, the concentration reachesbalance. The mass transfer coefficient of glucose、lactose、L-phenylalanine、glutamicacid are0.094,0.084,0.108,0.124.Then study the3cyst components：SA, CMC and CaCl2and the BC of calciumalginate gel bead cyst and Pediococcus acidilacticii cell, the result find out thatSA,CMC is beneficial for the growth and reproduction of the thallus, and CaCl2just haslittle influence to the thallus, this result proves that the BC of calcium alginate gel beadcyst and Pediococcus acidilacticii cell is well. Immobilized culture the immobilizedPediococcus acidilacticii, in48h, the density of the thallus reaches the highest, which is1011cfu/g. Choose the cell which is enrichment cultured for36h to immobilized ferment,the output of GABA is steady and fast, and also can recycle. Through thesemicontinuous fermentation for8batches, the output of the immobilized cell reachedthe highest8.07g/L in the first batch, and the average output for each batch is around7g/L.Finally, study the fermentation kinetics of the immobilized Pediococcusacidilactici under the best fermentation condition, and obtained the following model:microbial growth model: dx/dt=0.126(1-X/1.98)X;GABA growth model:dp/dt=0.049(dx/dt)+0.073X;L-MSG consumption model:-(ds/dt)=8.06(dx/dt)+1.1(dp/dt), andconduct confirmatory experiment based on this, the confirmatory experiment shows thatthe model can describe the experimental process quite well.