Study On Separation And Purification Of Amino Acids In Waste Threonine Mother Liquor

Threonine is mainly producted by fermentation. In order to obtain pure threonine, a series of physical and chemical separation processes must be applied.after the fermentation broth of threonine pass the technology of crystal unit, threonine mother liquor is producted largely in which many impurities are intermingled, e.g, threonine, other amino acids, residual sugars, proteins, pigments, colloids, inorganic salts and residual raw materials.if these mother liquor is directly put out into environment or selled for feedstuff additive factory, not only the value of them fall, but also they make large pollution. So It is very important of renewly making use of them.In this paper, Threonine mother liquor was used as the main materials. The content of mother liquor components, building analytic methods of amino acids, decoloring and the separation of amino acids in mother liquor were studied systematacially in order to gain the new and more effectively reactive ways, which could supply the technical foundation for the industry in some degree.1.In order to confirm separation objects, The componens of mother liquor were detailedly Analysed. the results show they include 20.24% solid matter(7.8%threonine, 6.9%glutamic Acid, 1.4% residual sugars, 2.28% inorganic salts and 1.66% proteins etc) and 79.76% water.2.The method of quantitative determination of threonine and glutamic acid were investigated by clorimetry in the principle of colorreaction between amino acids and ninhydrin, and mainly discuss the effect factors, reaction conditions and points for attention of this colorreaction. The best conditions of clorimetry were heat time 35minute,pH6.0,temperature100℃,laying 6minute. compared with the HPLC detection method, It was simple and economical by which the concentration of total amino acid of threonine mother liquor can be rnpidly and accurately detected.3.The decoloring conditions of threonine mother liquor are studied by active carbon and 717 resin. the best decoloring conditions of active carbon include 1.2g per 50ml mother liquor, 50℃, pH6.0 and decoloring 30min. in the condition, the decoloring rate is 91%, and the loss of amino acid is 10%.then 717 resin: emperature25℃, velocity of Flow 0.167BV/min. Grads washing of 0.2N sodium chloride and hydrochloric acid can separate amino acids and pigments in effect.in the condition, the decoloring rate is 90%, and the loss of amino acid is 12%.4.The separation of threonine and glumatic acid was studied by ion exchange and chromatog- rnphy technology. inorganic salts in threonine mother liquor resin have great effect on adsorption of threonine by D001 resin. So We select chromatogrnphy separation.separation degree of threonine and glumatic acid is 2.7, but chromatogrnphy peak of threonine was a big width. the study of chromatogrnphy technology condition showed temperature play a small role on separation of amino acid; velocity of flow have great effect on separation, and so thre- onine chromatogrnphy peak width is better improved.at the same time,the retention of glucose NH4Cl and NaCl was studied on chromatogrnphy column.the result show threonine and these matters were separated,and reach the aim of purification.