【作者】 楼良旺；

【导师】 高年发；

【作者基本信息】 天津科技大学 ， 发酵工程， 2005， 硕士

【摘要】 本文着重研究了丙酮酸发酵液中丙酮酸的提取、纯化和浓缩工艺。 1.建立了测定发酵液中丙酮酸含量的紫外分光光度法。在pH11.0的水溶液中,丙酮酸在320nm波长有吸收,而其他有机酸和杂质的干扰很小(相对误差小于3%),丙酮酸含量在0.2～2.8g/L范围内符合比耳定律。该法具有准确度高、重现性好、简便快速等特点,适合于生产过程发酵液中丙酮酸及其盐类的测定。 2.确定了采用离子交换法提取丙酮酸的工艺。(1)选用732型阳离子树脂为丙酮酸发酵液的脱色剂和阳离子交换剂,把脱色和改性两道工序合并,简化了提取丙酮酸的环节,从而提高了丙酮酸的提取收率。(2)从6种碱性阴离子交换树脂中选出D315弱碱性阴离子树脂(OH~-型)用于提取丙酮酸。采用较佳的工艺条件进行固定床单柱操作,实验得到离子交换单元的丙酮酸收率为96.60%。(3)提出了套用洗脱的构想。采用套用洗脱,不用增加阴离子固定床的高度就能将丙酮酸和洗脱剂盐酸充分分离,并且收集得到的纯丙酮酸质量浓度高,其高馏分段丙酮酸质量浓度在400g/L左右,充分体现了离子交换法的浓缩作用;套用洗脱第30个阴离子固定床后,丙酮酸累计回收率达95.67%。 3.初步研究了分子蒸馏法浓缩丙酮酸的工艺。对质量分数为15%～30%的丙酮酸,在操作压力为10Torr时,蒸馏温度控制在70℃,原料的适宜进料流速为120mL/h,刮膜器转子转速为30%。通过二步分子蒸馏,成品丙酮酸的质量浓度为99.01%,回收率89.99%以上。 通过以上研究,丙酮酸的总回收率达到81.22%以上,纯度为99.01%,各项指标均符合标准。更多还原

【Abstract】 The dissertation mainly focuses on the pyruvic acid processes of extraction, purifiction and concentration from the pyruvate fermentation broth.The method of determination of pyruvate’s content was studied by ultraviolet absorption spectrophotometry. At pH11.0 and 320nm, pyruvate could achieved high absorption than other organic acids and coexistent components. The concentration of pyruvate from 0.2 to 2.8g/L was just in accordance with Beer’s law. This method is simple and has high selectivity for the determination of pyruvate in the fermentation broth and its product.The ion-exchange method was studied. 732 cationic resin was chosen to decolour the fermentation broth besides to play the role of cation exchange. So the process was reduced and the recovery was enhanced for the pyruvic acid.D315 weakly-basic anion resin was selected for its superior performance to purify pyruvic acid. In the single fixed-bed ion-exchange operation, the recovery percent of pyruvic acid was 96.60%.An idea of elution in circles was suggested. By this method, pyruvic acid and hydrochloric acid could be separated enough without to add the height of anion fixed-bed. The concentration of pyruvic acid could achieve 400g/L which reflects the advantage of ion-exchange operation in concentration. After eluting 30 anion fixed-beds, the recovery percent of pure pyruvic acid obtained 95.67%.The molecule distillation also was studied. To the mass percent of pyruvic acid from 15 to 30, such conditions is optimal: 10Torr in pressure, 70℃ in temperature, the 120mL/h of flow rate, the 30% of rotate rate to rotor. After two steps of molecule distillation, the recovery percent of pure pyruvic acid was above 89.99% and its content achieved 99.01%.By above research, the total recovery of pyruvic acid was above 81.22%, purity achieved 99.01% and every items satisfied the standard.更多还原