Juhler Susanne, Revsbech Niels Peter, Schramm Andreas, Herrmann Martina, Ottosen Lars D M, Nielsen Lars Peter
Department of Biological Sciences, Aarhus University, Denmark.
Appl Environ Microbiol. 2009 Jun;75(11):3705-13. doi: 10.1128/AEM.02612-08. Epub 2009 Apr 10.
The in situ activity and distribution of heterotrophic and nitrifying bacteria and their potential interactions were investigated in a full-scale, two-section, trickling filter designed for biological degradation of volatile organics and NH(3) in ventilation air from pig farms. The filter biofilm was investigated by microsensor analysis, fluorescence in situ hybridization, quantitative PCR, and batch incubation activity measurements. In situ aerobic activity showed a significant decrease through the filter, while the distribution of ammonia-oxidizing bacteria (AOB) was highly skewed toward the filter outlet. Nitrite oxidation was not detected during most of the experimental period, and the AOB activity therefore resulted in NO(2)(-), accumulation, with concentrations often exceeding 100 mM at the filter inlet. The restriction of AOB to the outlet section of the filter was explained by both competition with heterotrophic bacteria for O(2) and inhibition by the protonated form of NO(2)(-), HNO(2). Product inhibition of AOB growth could explain why this type of filter tends to emit air with a rather constant NH(3) concentration irrespective of variations in inlet concentration and airflow.
在一个用于生物降解养猪场通风空气中挥发性有机物和NH₃的全尺寸两段式滴滤池中，研究了异养细菌和硝化细菌的原位活性、分布及其潜在相互作用。通过微传感器分析、荧光原位杂交、定量PCR和批次培养活性测量等方法对滤池生物膜进行了研究。原位需氧活性显示，整个滤池中的活性显著下降，而氨氧化细菌（AOB）的分布高度偏向滤池出口。在大部分实验期间未检测到亚硝酸盐氧化，因此AOB活性导致NO₂⁻积累，滤池入口处的浓度经常超过100 mM。滤池中AOB局限于出口部分的原因，一是与异养细菌竞争O₂，二是被NO₂⁻的质子化形式HNO₂抑制。AOB生长的产物抑制可以解释为什么这种类型的滤池无论入口浓度和气流如何变化，都倾向于排放NH₃浓度相当恒定的空气。
