精酮合剂(L-精氨酸-α-酮戊二酸盐,AAKG)是目前国际市场上销量日益增长的一种氨基酸盐类功能制品,通常的产品形式是混合型而非结晶型。实验直接以L-精氨酸(L-Arg)发酵液为原料,通过加入α-酮戊二酸(α-KG)进行络合,制备出结晶型精酮合剂,其主要工艺步骤和控制参数如下:首先对发酵液进行絮凝和过滤,并减压浓缩至L-Arg浓度为1.0 mol/L,再等摩尔加入α-KG进行络合,进一步减压浓缩使AAKG浓度达到1.5mol/L;浓缩液以2℃/h的速率缓慢降温至10℃,恒温结晶24 h,获得粗晶体,并再在同样的条件下进行重结晶。其精酮合剂纯度为99.2%,分子中L-Arg∶α-KG的摩尔比为1∶1.02,产品总收率为62.9%。

AAKG(L-arginine-alpha-ketoglutarate) is a functional product of amino acid salts with increasing sales in the current international market.The usual form of the product is hybrid rather than crystalline.Herein crystalline AAKG was prepared directly used L-arginine fermentation broth as the raw material and then complexation by adding α-ketoglutarate.The main process steps and control parameters were described as follows.Firstly the L-Arginine fermentation broth was flocculated and filtrated,and then concentrated under reduced pressure to a concentration of 1.0 mol/L.Then it was complexated by adding equimolar α-KG and further concentrated under reduced pressure so that the concentration of AAKG reached 1.5 mol/L.Crude crystals were obtained after the concentrate was cooled at a rate of 2 ℃/h and ultimately crystallized at 10 ℃ for 24h,and then it was recrystallized under the same conditions.The purity of AAKG was 99.2%.The ratio of L-Arg to α-KG was 1∶ 1.02.The total recovery ratio was 62.9%.