黄原胶发酵液纯化精制研究

Purification of xanthan gum fermentation broth

溶剂法直接提取的黄原胶产品含有大量菌体蛋白和色素杂质 ,总氮含量高、透明度差、色泽暗深。通过中性蛋白酶处理发酵液 ,使成品含氮量下降 5 6 .5 % ;通过Na2 SO3 漂白发酵液 ,使产品色泽大为改善。实验得出最佳酶解条件 :发酵液稀释 1倍 ,温度 44℃、pH7,加酶量 1 0 0u/ g发酵液 ,作用时间 2 .5h ;最佳Na2 SO3 漂白条件 :温度 2 0～ 30℃ ,pH5～ 6 ,Na2 SO3 用量为 1 % (w/w) ,作用时间 1～ 1 .5h。

The xanthan product recovered directly from fermentation broth with solvent contained lots of protein and pigment impurities.Its total nitrogen content was high, its color and transparency was poor. After the xanthan gum fermentation broth was treated with a neutral protease,the nitrogen content of xanthan gum product was reduced by 56.5%. The fermentation broth was also bleached by Na 2SO 3 , and the color of the xanthan products was greatly improved. The experiment showed that the optimal enzyme degrading conditions were as follows:44 ℃, pH 7,100 u/g broth of neutral protease concentration, reaction time 2.5 hours and the xanthan gum fermentation broth was diluted by 2 times with water at first; the optimized Na 2SO 3 bleaching conditions were 20～30℃, pH 5～6, Na 2SO 3 concentration 1%(w/w), reaction time 1～1.5 hours.