发酵体系中氨态氮含量的测定及影响因素的探讨

Determination of NH_4^+-N in Microbial Fermentation and Some In fluential Factors

靛酚蓝-分光光度法是一种灵敏度高、设备要求简单、线性相关性好、重现性高的氨态氮检测方法。本文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,确定了最佳的检测波长为637nm,最佳的反应条件为37℃、25 mg.L-1的催化剂和20 m in的反应时间。并由此得到一条线性相关系数为0.9996的氨态氮检测标准曲线。同时,对靛酚蓝法测定氨态氮用于普通发酵体系进行了探讨。对常用发酵基质如炭源、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用于氨态氮的测定。最后,将这种氨氮测定方法用于泰乐菌素和阿维菌素的发酵实践,取得了良好效果,由此证明该方法是一种切实可行的发酵中氨态氮的检测方法。

NH4^＋ - N is a very important factor on the production of metabolites by fermentation process especially on many types of secondary metabolites. Indophenol blue method has been proved high performance , high sensitivity and high reproducibility on NH4^＋ -N determination. Detection wavelength, reaction temperature, time and concentration of catalyst have been firstly studied. The best conditions of 37℃ reaction temperature, 20rain reaction time , 25mg·L^-1 catalyst and 637nm wavelength have been gained after optimization. Many factors about fermentation substrates such as glucose, corn steep liquor, Ca^2＋ , antifoam and so on have been studied by indophenol blue method. And the result indicated that normal substrate of the fermentation had no influence on NH4^＋- N determination.