VTT Biotechnology, P.O. Box 1000, Fin-02044 VTT, Espoo, Finland.
J Chromatogr A. 2010 Feb 26;1217(9):1537-42. doi: 10.1016/j.chroma.2009.12.075. Epub 2010 Jan 4.
Determination of carboxylic acids in Gluconobacter oxydans fermentations of wheat straw hydrolyzate was carried out. This matrix is of complex composition containing carbohydrates, organic compounds (e.g., amino acids, toxins), and inorganic salts making the analysis challenging even with separation techniques. A method based on capillary electrophoresis with indirect UV detection was developed for the simultaneous quantification of 18 carboxylic acids. The background electrolyte solution of ammonia, 2,3-pyridinedicarboxylic acid, and Ca2+ and Mg2+ salts, containing myristyltrimethylammonium hydroxide as a dynamic capillary coating reagent, was validated for the robust and repeatable separation of the carboxylic acids. Intraday relative standard deviations in the optimized method were less than 1.6% for migration times and between 1.0% and 5.9% for peak area. Interday relative standard deviations were less than 5.0% for migration times and between 5.7% and 9.3% for peak area. With 11 nl injected, detection limits for the analytes were between 10 and 43 micromol/l. Detection limits ranged from 0.1 to 0.5 pmol at signal-to-noise ratio of 3. The results demonstrated that wheat straw hydrolyzate was a suitable substrate for G. oxydans with a product yield of 45% for the formation of xylonic acid from xylose and 96% for the formation of gluconic acid from glucose.
测定了氧化葡萄糖酸杆菌发酵麦草水解物中的羧酸。该基质成分复杂，含有碳水化合物、有机化合物（如氨基酸、毒素）和无机盐，即使采用分离技术，分析也具有挑战性。建立了一种基于毛细管电泳-间接紫外检测法，用于同时定量分析 18 种羧酸。以氨、2,3-吡啶二羧酸和 Ca 2+、Mg 2+盐为背景电解质溶液，添加肉豆蔻基三甲基氢氧化铵作为动态毛细管涂层试剂，对羧酸进行了稳健且可重复的分离。在优化的方法中，日内相对标准偏差（RSD）小于 1.6%（迁移时间）和 1.0%-5.9%（峰面积）；日间 RSD 小于 5.0%（迁移时间）和 5.7%-9.3%（峰面积）。以 11 nl 进样，分析物的检测限为 10-43 μmol/L。在信噪比为 3 时，检测限范围为 0.1-0.5 pmol。结果表明，麦草水解物是氧化葡萄糖酸杆菌的合适底物，木糖生成戊二酸的产率为 45%，葡萄糖生成葡萄糖酸的产率为 96%。
