靛酚蓝-分光光度法测定发酵液中氨态氮含量研究

靛酚蓝-分光光度法是一种灵敏度高,对设备要求简单,线性相关性好,重现性高的氨态氮检测方法。文中对该方法的检测波长、反应温度、时间以及催化剂浓度等条件进行了优化,确定了检测波长为637 nm,反应条件为37℃、25 mg/L的催化剂和20 min的反应时间,并由此得到一条线性相关系数为0.999 6的氨态氮标准曲线。同时,对靛酚蓝法用于普通发酵体系测定氨态氮进行了探讨。对常用发酵基质如碳源、氮源、金属离子以及消泡剂等进行了考察,结果发现这些常用基质基本不影响本法的测定结果。最后,将该法用于泰乐菌素和阿维菌素的发酵液测定并与离子选择电极法进行了比较,两种方法的测定结果无显著性差异,由此证明该方法是一种准确可靠,切实可行的检测发酵液中氨态氮的方法。

Study on the Determination of NH4+-N Content in Microbial Fermentation Liquor by Indophenol Blue Spectrophotometric Method

Indophenol blue method has been proved as high performance,high sensitivity and high reproducibility on NH~+_4-N determination.Detection wavelength,reaction temperature,reaction time and catalyst concentration were studied and introduced in the first part of this paper.The best condition,which is 37℃ reaction temperature,20min reaction time,25mg/L catalyst and 637nm wavelength,has been obtained after optimization.A linear work curve of NH~+_4-N with R~2=(0.999 6) have been achieved.In the second part of this paper,many factors about fermentation substrates such as carbon sources,nitrogen sources,metal ion and antifoam agent have been studied.And the result of these studies indicated that normal substrate of fermentation process that list in this paper have no effect on NH~+_4-N determination by indophenol blue method.In the end,indophenol blue method has been proved to be an accurate operable method on NH~+_4-N determination of normal fermentation liquor through two practices of tylosin and avermectin production in 30 L fermentor and comparative assay with ion elective electrode method.