Microbial responses to membrane cleaning using sodium hypochlorite in membrane bioreactors: Cell integrity, key enzymes and intracellular reactive oxygen species
Microbial responses to membrane cleaning using sodium hypochlorite in membrane bioreactors: Cell integrity, key enzymes and intracellular reactive oxygen species
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DOI：
10.1016/j.watres.2015.10.033
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发表时间：
2016-01-01
期刊：
影响因子：
12.8
通讯作者：
Wu, Zhichao
中科院分区：
文献类型：
--
作者：
Han, Xiaomeng;Wang, Zhiwei;Wu, Zhichao
次氯酸钠（NaClO）是膜生物反应器（MBR）中常用的膜清洗剂，但其作为一种消毒剂（氧化剂），在膜清洗过程中会扩散到混合液中，损害微生物的生存能力，甚至使微生物完全死亡。在这项研究中，我们系统地研究了NaClO对微生物的影响，微生物细胞的完整性，代谢行为（关键酶），和细胞内活性氧（ROS）在不同的NaClO浓度。不同的NaClO剂量（5-50 mg/g-SS）在几分钟内破坏活性污泥中不同比例的微生物细胞，并相应地将有机物释放到本体溶液中。当NaClO浓度大于1 mg/g-SS时，有机物生物降解、硝化和反硝化过程中的关键酶活性受到抑制，有机物和氮的去除率降低。研究还表明，随着NaClO剂量高于1 mg/g-SS，细胞内ROS的产生增加，这可能诱导对微生物细胞的进一步损伤。(C)2015爱思唯尔有限公司版权所有。
Sodium hypochlorite (NaClO) is a commonly used reagent for membrane cleaning in membrane bio-reactors (MBAs), while it, being a kind of disinfectant (oxidant), may impair viability of microbes or even totally inactivate them upon its diffusion into mixed liquor during membrane cleaning. In this study, we systematically examine the effects of NaClO on microorganisms in terms of microbial cell integrity, metabolism behaviours (key enzymes), and intracellular reactive oxygen species (ROS) under various NaClO concentrations. Different proportions of microbial cells in activated sludge were damaged within several minutes dependent on NaClO dosages (5-50 mg/g-SS), and correspondingly organic matters were released to bulk solution. Inhibition of key enzymes involved in organic matter biodegradation, nitrification and denitrification was observed in the presence of NaClO above 1 mg/g-SS, and thus organic matter and nitrogen removal efficiencies were decreased. It was also demonstrated that intracellular ROS production was increased with the NaClO dosage higher than 1 mg/g-SS, which likely induced further damage to microbial cells. (C) 2015 Elsevier Ltd. All rights reserved.