JOURNAL OF HAZARDOUS MATERIALS
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2017
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IF 6.065
Zheng-Zhe Zhang,Jia-Jia Xu,Zhi-Jian Shi,Ya-Fei Cheng,Zheng-Quan Ji,Rui Deng,Ren-Cun Jin
Previous studies investigating the risk of engineered nanoparticles (NPs) to biological wastewater treatment have primarily tested NPs individually; however, limited data are available on the impact of NPs on the anaerobic ammonium oxidation (anammox) process. In this study, the toxicity of CuNPs on anammox granules was investigated individually and in combination with CuONPs or ZnONPs. Exposure to CuNPs at 5 mg g −1 suspended solids (SS) decreased the anammox activity to 47.1 ± 8.5%, increased the lactate dehydrogenase level to 110.5 ± 3.4% and increased the extracellular N 2 H 4 concentration by 16-fold but did not cause oxidative stress. The presence of CuONPs or ZnONPs at 5 mg g −1 SS did not significantly aggravate or alleviate the toxicity of the CuNPs; however, the introduction of EDTA or S 2− could attenuate the adverse effects of the CuNPs, CuONPs and ZnONPs on the anammox granules. EDTA captured Cu ions, whereas S 2− shielded and deactivated Cu ions and passivated CuNPs. Therefore, our results indicated that the toxicity of NPs was dependent on the amount of active metal reaching the anammox cells. Overall, the results of this study have filled knowledge gaps and provided insights into the combined toxicity of NPs on anammox biomass.
研究领域:
环境工程
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微生物学
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水处理技术
✓ 已验证
DOI
PubMed
高影响因子
JOURNAL OF ENVIRONMENTAL MANAGEMENT
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2024
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IF 8
Xun Weng,Meng-Jiao Gao,Zheng Mao,Hui-Min Fu,Shi-Jun Li,Peng Yan,You-Peng Chen
Iron nanoparticles (FeNPs) generated from industrial activities could end up into the sewer system, and potentially affect wastewater treatment processes. The impact of FeNPs on anammox process is getting increasing attention. However, the resistance mechanism of anammox granular sludge (AnGS) to FeNPs has not been fully elucidated. The current study investigated the metabolic and morphological response of AnGS to acute and chronic FeNPs exposure. Results showed that nitrogen removal efficiencies were elevated at 1–4 mM FeNPs concentrations compared to 0–0.5 mM FeNPs. Extracellular protein and tyrosine-like and tryptophan-like fluorophore secretions of AnGS were stimulated by FeNPs, which largely contributed to the adsorption of FeNPs on AnGS surface. FeNPs exposure triggered higher necrotic fraction of AnGS compared with no FeNPs condition. Highly absorbed particles appeared inside the bacterial cells of AnGS, soft X-ray imaging illustrated that anammox bacteria maintained intact cellular and anammoxosome structures whereas non-anammox bacterial structures were damaged under FeNPs exposure. Anammox bacterial abundance increased from 4.84% to 20.64%, when FeNPs concentrations increased from 0 mM to 4 mM, and anammoxosome membrane ensured anammox bacterial metabolism under FeNPs exposure. This study extended fundamental understanding of AnGS resistance mechanisms to FeNPs.
研究领域:
环境科学
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微生物学
✓ 已验证
DOI
PubMed
高影响因子
CHEMOSPHERE
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2020
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IF 5.778
Weigang Wang,Yuan Yan,Junjie Wang,Yijing Zhu,Jie Ma,Zhuwu Jiang,Yayi Wang
Extracellular proteins are crucial for the formation and structural maintenance of anammox granules. However, the influence of extracellular polymeric substances (EPS) extraction methods on the secondary structure of extracellular proteins has not been studied fully. In this work, ten EPS extraction methods were applied to anammox granules and compared systematically. The EPS extraction methods were then applied to bovine serum albumin (BSA), a representative of extracellular proteins, to investigate their influence on protein secondary structure by circular dichroism (CD) spectroscopy. The ten EPS extraction methods yielded EPS concentration varying from 5.2 ± 0.1 to 84.8 ± 2.0 mg/g volatile suspended solid (VSS). Tween-20 treatment resulted in the most similar CD spectrum and protein secondary structure to the control. Treatment 0.5% Tween-20 for 4 h was found to be the best condition to preserve protein secondary structure while achieving a high EPS yield (44.4 ± 1.4 mg/g VSS) and limited cell lysis for anammox granules. This study provides an optimized protocol to extract granular EPS when the role of the secondary structure of extracellular proteins in regulating aggregation, adsorption and biofilm formation of microbes is to be elucidated.
研究领域:
环境生物学
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微生物学
✓ 已验证
产品关联
DOI
高影响因子
Water Research X
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2024
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IF 7.2
Dongdong Xu,Aqiang Ding,Yang Yu,Ping Zheng,Meng Zhang,Zhetai Hu
Magnetite (Fe 3 O 4 ) particles have been widely reported to enhance the anammox's activity in anammox granular sludge (AnGS), yet the underlying mechanisms remain unclear. This study demonstrates that both Fe 3 O 4 microparticles (MPs) and nanoparticles (NPs) at a dosage of 200 mg Fe 3 O 4 /L significantly increased the specific anammox activity (SAA) of AnGS. Additionally, the transcriptional activities of the hzs and hdh genes involved in the anammox process, as well as the heme c content in AnGS, were also notably enhanced. Notably, Fe 3 O 4 NPs were more effective than MPs in boosting anammox activity within AnGS. Mechanistically, Fe 3 O 4 MPs released free iron, which anammox bacteria utilized to promote the synthesis of key enzymes, thereby enhancing their activity. Compared to MPs, Fe 3 O 4 NPs not only elevated the synthesis of these key enzymes to a higher level but also induced a nanofluids effect on the surface of AnGS, improving substrate permeability and accessibility to intragranular anammox bacteria. Moreover, the nanofluids effect was identified as the primary mechanism through which Fe 3 O 4 NPs enhanced anammox activity within AnGS. These findings provide new insights into the effects of nanoparticles on granular sludge systems, extending beyond AnGS.
研究领域:
环境工程
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微生物学
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生物技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ENVIRONMENTAL RESEARCH
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2024
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IF 7.7
Andong Zhao,Jun Li,Peng Gao,Peng Tang,Tingting Liu,Xin Zhang,Xuming Liu,Cong Chen,Zehao Zhang,Zhaoming Zheng
Tetramethylammonium hydroxide (TMAH), an extensively utilized photoresist developer, is frequently present in ammonium-rich wastewater from semiconductor manufacturing, and its substantial ecotoxicity should not be underestimated. This study systematically investigated the effects of TMAH on the anammox granular sludge (AnGS) system and elucidated its inhibitory mechanisms. The results demonstrated that the median inhibitory concentration of TMAH for anammox was 84.85 mg/L. The nitrogen removal performance of the system was significantly decreased after long-term exposure to TMAH (0 - 200 mg/L) for 30 days ( p < 0.05), but it showed adaptability to certain concentrations (≤ 50 mg/L). Concurrently, the stability of the granules decreased dramatically, resulting in the breakdown of AnGS. Further investigations indicated that TMAH exposure increased the secretion of extracellular polymeric substances but weakened their defense function. The increase in reactive oxygen species resulted in damage to the cell membrane. Reduced activity of anammox bacteria, impeded electron transfer, and changes in enzyme activity suggested that TMAH affected the metabolic activity. Microbiological analysis revealed that TMAH caused a decrease in the abundance of anammox bacteria and a weakening of symbiotic interactions within the microbial community. These results provide valuable guidance for the AnGS system application in chip wastewater treatment.
研究领域:
环境工程
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废水处理
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微生物学
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生物技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）