Biological removal of selenite from wastewater and recovery as selenium nanoparticles using inverse fluidized bed bioreactor

Sinharoy, Arindam; Saikia, Sudeshna; Pakshirajan, Kannan

doi:10.1016/j.jwpe.2019.100988

Cited by 45 publications

(23 citation statements)

References 50 publications

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“…The comparison is based on 50 TEM images like those shown in Figure . They are also consistently lower than the numbers (10–99%) reported in previous studies with conventional reactors. − …”

Section: Resultsmentioning

confidence: 43%

Evidence and Mechanisms of Selenate Reduction to Extracellular Elemental Selenium Nanoparticles on the Biocathode

Zhang

Asefaw

Xiong

et al. 2022

Environ. Sci. Technol.

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Intracellular selenium nanoparticles (SeNPs) production is a roadblock to the recovery of selenium from biological water treatment processes because it is energy intensive to break microbial cells and then separate SeNPs. This study provided evidence of significantly more extracellular SeNP production on the biocathode (97−99%) compared to the conventional reactors (1−90%) using transmission electron microscopy coupled with energy-dispersive X-ray spectroscopy. The cathodic microbial community analysis showed that relative abundance of Azospira oryzae, Desulfovibrio, Stenotrophomonas, and Rhodocyclaceae was <1% in the inoculum but enriched to 10−21% for each group when the bioelectrochemical reactor reached a steady state. These four groups of microorganisms simultaneously produce intracellular and extracellular SeNPs in conventional biofilm reactors per literature review but prefer to produce extracellular SeNPs on the cathode. This observation may be explained by the cellular energetics: by producing extracellular SeNPs on the biocathode, microbes do not need to transfer selenate and the electrons from the cathode into the cells, thereby saving energy. Extracellular SeNP production on the biocathode is feasible since we found high concentrations of C-type cytochrome, which is well known for its ability to transfer electrons from electrodes to microbial cells and reduce selenate to SeNPs on the cell membrane.

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Section: Resultsmentioning

confidence: 43%

Evidence and Mechanisms of Selenate Reduction to Extracellular Elemental Selenium Nanoparticles on the Biocathode

Zhang

Asefaw

Xiong

et al. 2022

Environ. Sci. Technol.

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“…In another study, Sinharoy et al. (2019) reported 58% selenium recovery from synthetic wastewater at pH 7.0 using IFBR.…”

Section: Resultsmentioning

confidence: 98%

Heavy metal removal and recovery as nanoparticles from multicomponent system at low pH condition by biogenic sulfide precipitation using anaerobic sulfate reducing biomass

Kumar

Pakshirajan

2022

Environmental Quality Mgmt

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Acid mine drainage (AMD) represents an environmental and human health hazard in many countries with historic or ongoing mining industries. Biological sulfide precipitation is an emerging technique for recovery of heavy metals from such wastewater.This study reports heavy metal removal and recovery from multicomponent system containing Cd 2+ , Cu 2+ , Pb 2+ , Zn 2+ , Ni 2+ , and Fe 2+ at low pH condition by anaerobic sulfate-reducing biomass. Plackett-Burman design of experiments was employed to carry out this mixture study and evaluate the combined effect of these metals on their recovery as nanoparticles. The maximum removal was observed in case of Cd 2+ (100%) and Cu 2+ (100%), followed by that for Pb 2+ (99%), Zn 2+ (98%), Ni 2+ (88.2%), and Fe 2+ (64%). The metals were recovered in the form of metal sulfide nanoparticles, and the metal recovery was in the order: Cu > Pb > Cd > Zn > Fe > Ni. Analysis of nanosized metal bioprecipitate by field emission scanning electron microscopy (FESEM) and energy-dispersive X-ray spectroscopy (EDX) confirmed the role of biogenic sulfide in the process. The size and shape of the metal nanoparticles were confirmed using field emission transmission electron microscopy, which revealed their excellent potential for industrial application. This study demonstrates successful recovery of metal sulfides in the form of nanoparticles using SRB from a multicomponent system at low pH condition.

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“…may have implications for the properties SeNPs. Small-sized SeNPs (<50 nm approximately) tend to have lower sedimentation capacity and, therefore, higher mobility . In addition, it is generally assumed that the antimicrobial properties of NPs are size-dependent, and smaller NPs can interact and enter more easily and thus damage cells .…”

Section: Resultsmentioning

confidence: 99%

Exploring Antibacterial Activity and Bacterial-Mediated Allotropic Transition of Differentially Coated Selenium Nanoparticles

Ruiz-Fresneda

Schaefer

Hübner

et al. 2023

ACS Appl. Mater. Interfaces

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The use of metal nanoparticles (NPs) as antimicrobial agents has become a promising alternative to the problem of antibiotic-resistant bacteria and other applications. Silver nanoparticles (AgNPs) are well-known as one of the most universal biocide compounds. However, selenium nanoparticles (SeNPs) recently gained more attention as effective antimicrobial agents. This study aims to investigate the antibacterial activity of SeNPs with different surface coatings (BSA-coated, chitosan-coated, and undefined coating) on the Gram-negative Stenotrophomonas bentonitica and the Gram-positive Lysinibacillus sphaericus in comparison to AgNPs. The tested NPs had similar properties, including shape (spheres), structure (amorphous), and size (50−90 nm), but differed in their surface charge. Chitosan SeNPs exhibited a positive surface charge, while the remaining NPs assayed had a negative surface charge. We have found that cell growth and viability of both bacteria were negatively affected in the presence of the NPs, as indicated by microcalorimetry and flow cytometry. Specifically, undefined coating SeNPs displayed the highest percentage values of dead cells for both bacteria (85−91%). An increase in reactive oxygen species (ROS) production was also detected. Chitosan-coated and undefined SeNPs caused the highest amount of ROS (299.7 and 289% over untreated controls) for S. bentonitica and L. sphaericus, respectively. Based on DNA degradation levels, undefined-SeNPs were found to be the most hazardous, causing nearly 80% DNA degradation. Finally, electron microscopy revealed the ability of the cells to transform the different SeNP types (amorphous) to crystalline SeNPs (trigonal/monoclinical Se), which could have environmentally positive implications for bioremediation purposes and provide a novel green method for the formation of crystalline SeNPs. The results obtained herein demonstrate the promising potential of SeNPs for their use in medicine as antimicrobial agents, and we propose S. bentonitica and L. sphaericus as candidates for new bioremediation strategies and NP synthesis with potential applications in many fields.

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Biological removal of selenite from wastewater and recovery as selenium nanoparticles using inverse fluidized bed bioreactor

Cited by 45 publications

References 50 publications

Evidence and Mechanisms of Selenate Reduction to Extracellular Elemental Selenium Nanoparticles on the Biocathode

Evidence and Mechanisms of Selenate Reduction to Extracellular Elemental Selenium Nanoparticles on the Biocathode

Heavy metal removal and recovery as nanoparticles from multicomponent system at low pH condition by biogenic sulfide precipitation using anaerobic sulfate reducing biomass

Exploring Antibacterial Activity and Bacterial-Mediated Allotropic Transition of Differentially Coated Selenium Nanoparticles

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