Seenivasagham Vimala, K C Bal Krishna, Chandy Joseph P, Kastl George, Blackall Linda L, Rittmann Bruce, Sathasivan Arumugam
School of Engineering, Design and Built Environment Western Sydney University, NSW, 2747, Australia.
School of BioSciences, University of Melbourne, VIC, 3010, Australia.
Chemosphere. 2024 Jul;359:142341. doi: 10.1016/j.chemosphere.2024.142341. Epub 2024 May 14.
This work comprehensively demonstrates the ability of heterotrophic bacteria, isolated from a chloraminated system, to decay chloramine. This study non-selectively isolated 62 cultures of heterotrophic bacteria from a water sample (0.002 mg-N/L nitrite and 1.42 mg/L total chlorine) collected from a laboratory-scale reactor system; most of the isolates (93.3%) were Mycobacterium sp. Three species of Mycobacterium and one species of Micrococcus were inoculated to a basal inorganic medium with initial concentrations of acetate (from 0 to 24 mg-C/L) and 1.5 mg/L chloramine. Bacterial growth coincided with declines in the concentrations of chloramine, acetate, and ammonium. Detailed experiments with one of the Mycobacterium sp. isolates suggest that the common mechanism of chloramine loss is auto-decomposition likely mediated by chloramine-decaying proteins. The ability of the isolates to grow and decay chloramine underscores the important role of heterotrophic bacteria in the stability of chloramine in water-distribution systems. Existing strategies based on controlling nitrification should be augmented to include minimizing heterotrophic bacteria.
这项工作全面展示了从氯化系统中分离出的异养细菌分解氯胺的能力。本研究从实验室规模的反应器系统采集的水样（0.002 mg-N/L亚硝酸盐和1.42 mg/L总氯）中无选择性地分离出62种异养细菌培养物；大多数分离株（93.3%）为分枝杆菌属。将三种分枝杆菌和一种微球菌接种到初始浓度为乙酸盐（0至24 mg-C/L）和1.5 mg/L氯胺的基础无机培养基中。细菌生长与氯胺、乙酸盐和铵浓度的下降同时发生。对其中一种分枝杆菌属分离株进行的详细实验表明，氯胺损失的常见机制可能是由氯胺分解蛋白介导的自分解。分离株生长和分解氯胺的能力突出了异养细菌在配水系统中氯胺稳定性方面的重要作用。基于控制硝化作用的现有策略应加以扩充，包括尽量减少异养细菌。
