Different susceptibilities of bacterial community to silver nanoparticles in wastewater treatment systems

Jeong, Eui-Rim; Im, Wan Taek; Kim, Dong-Hoon; Kim, Mi-Sun; Kang, Seoktae; Shin, Hang-Sik; Chae, So-Ryong

doi:10.1080/10934529.2014.865454

Cited by 50 publications

(15 citation statements)

References 31 publications

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“…Beside of nCeO 2 , other engineered metal oxides-NPs such as nAg NPs (Das et al 2012), nZnO NPS (Meli et al 2016) and TiO2 NPs (Shah et al 2014) have also been reported to have toxic effects on microbial community from several ecosystem. Jeong et al (2014) also revealed the impact of nAg-NPs on bacterial community from wastewater treatment systems. These authors revealed that nitrifying bacteria are most susceptible to NPs such as nAg.…”

Section: Discussionmentioning

confidence: 99%

Impacts of cerium oxide nanoparticles on bacterial community in activated sludge

Kamika

Tekere

2017

AMB Expr

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Rapidly developing industry raises concerns about the environmental impacts of nanoparticles, but the effects of inorganic nanoparticles on bacterial community in wastewater treatment remain unclear. The present research assessed the impact of cerium oxide nanoparticles (nCeO) on the microbiome of activated sludge system. The results showed that 18,330 over 28,201 reads generated from control samples were assigned to Proteobacteria while 5527 reads (19.6%), 3260 reads (11.567%), and 719 reads (2.55%) were assigned to unclassified_Bacteria, Firmicutes and Actinobacteria, respectively. When stressed with nCeO2 NPs, a decrease on reads was noted with 53, 48, 27.7 and 24% assigned to Proteobacteria. Gammaproteobacteria (80.57%) was found to be the most predominant Proteobacteria. The impact of nCeO2 NPs was also observed on pollutants removal as only 1.83 and 35.15% of phosphate and nitrate could be removed in the bioreactor stressed with 40 mg-nCeO2-NPs/L. This was confirmed by a drastic reduction of activities for enzymes catalysing denitrification (NaR and NiR) and degradation of polyphosphate (ADK and PPK). ADK appeared to be the most affected enzyme with activity decrease reaching over 90% when stressed with 10 mg-nCeO2/L. Furthermore, bacterial diversity was not significantly different whereas their species richness showed significant difference between control and treated samples. A large number of reads from control samples could not be classified down to the lower taxonomic level “genera” suggesting hitherto vast untapped microbial diversity. The denitrification related genera including Trichococcus and Acinetobacter were found to alternatively dominating treated samples highlighting those nCeO2 NPs could enhance the growth of some bacterial species while inhibiting those of others. Nevertheless, the study indicates that nCeO2 NPs in wastewater at very high concentrations may have some adverse effects on activated sludge process as they inhibit the removal of phosphate.Electronic supplementary materialThe online version of this article (doi:10.1186/s13568-017-0365-6) contains supplementary material, which is available to authorized users.

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Section: Discussionmentioning

confidence: 99%

Impacts of cerium oxide nanoparticles on bacterial community in activated sludge

Kamika

Tekere

2017

AMB Expr

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“…At sublethal concentrations, Ag-NPs can upregulate amoA ( Yang et al, 2013 ). A few reports have documented the adverse effects of Ag-NPs on nutrient removal from wastewater are dose dependent and nutrient removal can recover with time ( Chen et al, 2013 ; Alito and Gunsch, 2014 ; Jeong et al, 2014 ). The effects of Ag-NPs on other microbial functional groups in biological wastewater treatment systems are far less well studied.…”

Section: Introductionmentioning

confidence: 99%

The effects of silver nanoparticles on intact wastewater biofilms

et al. 2015

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Silver nanoparticles (Ag-NPs) have strong antibacterial properties, which may adversely affect biological wastewater treatment processes. To determine the overall effect, intact biofilm samples were collected from the rotating biological contactor at the local wastewater treatment plant and treated with 200 mg Ag/L Ag-NPs for 24 h. The biofilm uptake of Ag-NPs was monitored with transmission electron microscopy. Forty-five minutes after Ag-NP application, Ag-NPs were seen in the biofilm extracellular polymeric substances (EPS). After 24 h, Ag-NPs had entered certain microbial cells, while other cells contained no observable Ag-NPs. Some cells were dying after the uptake of Ag-NPs. However, there was no significant reduction in cultivable bacteria in the biofilms, based on heterotrophic plate counts (HPC). While this may indicate that wastewater biofilms are highly resistant to Ag-NPs, the HPC represents only a small portion of the total microbial population. To further investigate the effects of Ag-NPs, a GeoChip microarray was used to directly detect changes in the functional gene structure of the microbial community in the biofilm. A clear decrease (34.6% decreases in gene number) in gene diversity was evident in the GeoChip analysis. However, the complete loss of any specific gene was rare. Most gene families present in both treated and untreated biofilms. However, this doesn’t necessarily mean that there was no change in these families. Signal intensity decreased in certain variants in each family while other variants increased to compensate the effects of Ag-NPs. The results indicate that Ag-NP treatment decreased microbial community diversity but did not significantly affect the microbial community function. This provides direct evidence for the functional redundancy of microbial community in engineered ecosystems such as wastewater biofilms.

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“…AgNPs are believed to interfere with essential bacterial cell functions upon contact 6 , although the exact mechanism of the antimicrobial effect is still subject to debate 7 . However, after their intended use, the waste nanoparticles are hard to recover or deactivate in solid-waste incineration plants 8 or wastewater treatment systems 9 . Over time, processes such as sulphidation may convert the AgNPs to a less hazardous form 10 , but the long exposure of their core in the environment 11,12 and prolonged activity after their intended application 13 may adversely affect many ecosystems 14,15 .…”

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confidence: 99%

An environmentally benign antimicrobial nanoparticle based on a silver-infused lignin core

et al. 2015

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Silver nanoparticles have antibacterial properties, but their use has been a cause for concern because they persist in the environment. Here, we show that lignin nanoparticles infused with silver ions and coated with a cationic polyelectrolyte layer form a biodegradable and green alternative to silver nanoparticles. The polyelectrolyte layer promotes the adhesion of the particles to bacterial cell membranes and, together with silver ions, can kill a broad spectrum of bacteria, including Escherichia coli, Pseudomonas aeruginosa and quaternary-amine-resistant Ralstonia sp. Ion depletion studies have shown that the bioactivity of these nanoparticles is time-limited because of the desorption of silver ions. High-throughput bioactivity screening did not reveal increased toxicity of the particles when compared to an equivalent mass of metallic silver nanoparticles or silver nitrate solution. Our results demonstrate that the application of green chemistry principles may allow the synthesis of nanoparticles with biodegradable cores that have higher antimicrobial activity and smaller environmental impact than metallic silver nanoparticles.

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Different susceptibilities of bacterial community to silver nanoparticles in wastewater treatment systems

Cited by 50 publications

References 31 publications

Impacts of cerium oxide nanoparticles on bacterial community in activated sludge

Impacts of cerium oxide nanoparticles on bacterial community in activated sludge

The effects of silver nanoparticles on intact wastewater biofilms

An environmentally benign antimicrobial nanoparticle based on a silver-infused lignin core

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