Institute of Chemical Technology, Department of Chemical Engineering, Czechoslovakia.
Biotechnol Bioeng. 1991 Aug 5;38(4):323-30. doi: 10.1002/bit.260380402.
The reliability of dynamic measurement methods of k(l)a in fermentors using a step oxygen concentration change in the feed gas was tested. The tests were performed both for the original variant using the nitrogen right harpoon over left harpoon air exchange and the newly presented variant using the oxygen-enriched air (27 vol % O(2)) --> air exchange. The testing consisted in comparing k(l)a values determined from these methods with values determined from the steady-state Na(2)SO(3) feeding method and the dynamic pressure method, the reliability of which was proven earlier. The measurements were done in water (coalescent batch) and in 0.5M Na(2)SO(4) solution with and without the addition of 1 wt % carboxymethylcellulose (noncoalescent batches). It was found that in noncoalescent liquids the methods tested give extremely low k(l)a values (as low as 15% of the correct value). The methods are defective in principle irrespective of the gases used for exchange.
使用进料气体中氧浓度阶跃变化的方法来测试发酵罐中 k(l)a 的动态测量方法的可靠性。对原始变体（使用氮气右叉超过左叉空气交换）和新提出的变体（使用富氧空气（27 vol % O(2)）-->空气交换）进行了测试。测试包括将这些方法确定的 k(l)a 值与从稳态 Na(2)SO(3)进料方法和动态压力方法确定的值进行比较，这些方法的可靠性此前已得到证明。测量是在水中（凝聚批处理）和 0.5M Na(2)SO(4)溶液中进行的，有和没有添加 1wt%羧甲基纤维素（非凝聚批处理）。结果发现，在非凝聚液体中，所测试的方法给出了极低的 k(l)a 值（低至正确值的 15%）。无论使用哪种气体进行交换，这些方法在原理上都存在缺陷。
