基于氧微电极的生物膜内异养菌衰减系数的原位测定

In-situ Determination of Endogenous Decay Rate of Heterotrophic Biofilm by Microelectrodes

以分离式氧微电极为测试工具,在优化了电极结构的基础上,对内源呼吸状态的生物膜内部的溶解氧分布进行了准确测定,通过生物膜内扩散-反应过程的分析,拟合获得了生物膜内异养菌的衰减系数.结果表明,经过结构优化后,氧微电极的信号波动范围由优化前的(1.64±0.25)nA降低到优化后的(1.53±0.06)nA,波动抑制比为19.41 dB,输出信号的稳定性增强.用原位测定方法获得的生物膜内异养菌在处于内源呼吸状态时的呼吸速率为2.979 mg.h-1,衰减系数为0.005 9 h-1.

A separated oxygen microelectrode was constructed, based on the improved structure, to determine the oxygen distribution in biofilm at an endogenous state. Based on the diffusion-reaction model, the endogenous decay rate was evaluated by curve-fitting with the measured oxygen profiles. The results showed that the fluctuation range of output signal of oxygen microelectrode was reduced from （1.64 ±0.25）nA to （1.53 ± 0.06）hA, the signal became stable with the fluctuation rejection ratio of 19.41 dB after the structural optimization. The endogenous respiration rate and the endogenous decay rate of heterotrophic biofilm were evaluated to be 2. 979 mg· h ^- 1 and 0. 005 9 h^- 1.