Reduction of hexavalent chromium by Pannonibacter phragmitetus LSSE-09 coated with polyethylenimine-functionalized magnetic nanoparticles under alkaline conditions

Xu, Lin; Yang, Liangrong; Luo, Mingfang; Liang, Xia; Wei, Xuetuan; Zhao, Junmei; Liu, Huizhou

doi:10.1016/j.jhazmat.2011.03.009

Cited by 43 publications

(25 citation statements)

References 46 publications

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“…The spectrum of bare MNPs (Figure 2a) shows the characteristic Fe−O vibration band for magnetite at 587 cm −1 . 28 The binding of 20 kDa linear polymethacrylic acid onto the MNPs surface resulted in the appearance of new bands at 1190, 1430, 1546, 1701, and 2954 cm −1 (see Figure 2b, LPMAA20-MNPs). The absorption band at 1190, 1430, and 1701 cm −1 can be assigned respectively to the C−O stretching, −CH 2 − scissoring, and carbonyl (CO) stretching vibrations of the adsorbed polymethacrylic acid, whereas the one at 2954 cm −1 can be assigned to the stretching vibrations of both −CH 2 − and −CH 3 .…”

Section: ■ Results and Discussionmentioning

confidence: 98%

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Insight into Serum Protein Interactions with Functionalized Magnetic Nanoparticles in Biological Media

Wiogo¹,

Lim

Bulmuş³

et al. 2012

Langmuir

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Surface modification with linear polymethacrylic acid (20 kDa), linear and branched polyethylenimine (25 kDa), and branched oligoethylenimine (800 Da) is commonly used to improve the function of magnetite nanoparticles (MNPs) in many biomedical applications. These polymers were shown herein to have different adsorption capacity and anticipated conformations on the surface of MNPs due to differences in their functional groups, architectures, and molecular weight. This in turn affects the interaction of MNPs surfaces with biological serum proteins (fetal bovine serum). MNPs coated with 25 kDa branched polyethylenimine were found to attract the highest amount of serum protein while MNPs coated with 20 kDa linear polymethacrylic acid adsorbed the least. The type and amount of protein adsorbed, and the surface conformation of the polymer was shown to affect the size stability of the MNPs in a model biological media (RPMI-1640). A moderate reduction in r 2 relaxivity was also observed for MNPs suspended in RPMI-1640 containing serum protein compared to the same particles suspended in water. However, the relaxivities following protein adsorption are still relatively high making the use of these polymer-coated MNPs as Magnetic Resonance Imaging (MRI) contrast agents feasible. This work shows that through judicious selection of functionalization polymers and elucidation of the factors governing the stabilization mechanism, the design of nanoparticles for applications in biologically relevant conditions can be improved.

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Section: ■ Results and Discussionmentioning

confidence: 98%

“…This band corresponds to secondary C−N stretching vibration. 28 The strong absorption is due to the higher amount of C−N bond on the surface, which is an indication of the higher amount of linear polyethylenimine adsorbed on the MNPs surface compared to branched polyethylenimine.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Insight into Serum Protein Interactions with Functionalized Magnetic Nanoparticles in Biological Media

Wiogo¹,

Lim

Bulmuş³

et al. 2012

Langmuir

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“…To enhance the bio-adsorption of heavy metals, some methods had also researched such as polymers modification by EDTAD [35] and polyethylenimine (PEI) [19] to enlarge the effect of magnetic field on the bacterial negative surface charge. Xu et al [19] coated Pannonibacter phragmitetus LSSE-09 with PEI-modified magnetic nanoparticles to increase the adsorption of anion-Cr by neutralizing the negative-charged bacterial cells.…”

Section: Journal Of Adhesion Science and Technology 2203mentioning

confidence: 99%

“…[17] In recent years, magnetic field has been considered as a great potential in improving the process of biosorption and separation. [18][19][20] Optimal magnetic field intensity even could strengthen the biological wastewater treatment under low temperature. [20] But few mechanisms are established to explain the effect of magnetic field on the bacterial property.…”

Section: Introductionmentioning

confidence: 99%

Effect of magnetic field on surface properties ofBacillus cereusCrA and its Extracellular Polymeric Substances (EPS)

Hou

Ruan

et al. 2014

Journal of Adhesion Science and Technology

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The effect of magnetic field on surface properties of Bacillus cereus CrA and its EPS was studied by zeta potential and FT-IR spectrum. The weak magnetic fields of 6.0-10.0 mT promoted the predominant strain B. cereus CrA to form EPS. The weak magnetic field of 2.4-10.0 mT could improve the bio-adsorption efficiency of anions by decreasing the negative charge of the intact strain, while the magnetic field of 17.4 mT could increase the negative charge of the strain's EPS by 20% and be responsible for the bio-adsorption of cations. Magnetic field could affect the band intensity and the slight shifting of peaks and the fluctuation of the bacterial absorption capability depended on the magnetic density. The magnetic field energy could affect the hydroxyl group and carboxyl group by forming hydrogen bonding, which were responsible for the adsorption ability of the strain and its EPS.

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“…Electron microscopic observations of Cr precipitation using Cr(VI)-reducing bacteria have shown the usefulness of those bacteria for the detoxification of Cr(VI)-contaminated environment [6][7][8][9]. However we and others result need more investigations to establish a method for an efficient precipitation of Cr(III) synthesized by Cr(VI)-reducing bacterium.…”

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confidence: 95%

Electron Microscopy and X-ray Analysis of Cr-Containing Precipitates Synthesized by Newly Isolated Actinobacterium, Flexivirga alba ST13T

Sugiyama

Sakaguchi

2014

Indian J Microbiol

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Chromium(Cr) precipitate synthesized by Cr(VI)-reducing bacterium Flexivirga alba ST13 T was examined using transmission electron microscopy (TEM) and the energy dispersive X-ray (EDX). The strain showed altered-morphology after exposing to Cr(VI) in minimal medium. The resultant precipitate included bacterial pellet and needle-like structure which was similar to the structure made from Cr(OH) 3 precipitate. Cr was observed in bacterial cells using TEM-EDX. Bacteria with high electron density showed the precipitation of Ca in addition to Cr. The isolated strain would be useful to precipitate Cr from Cr(VI)-containing environment.Keywords Chromium Á Electron microscopy Á Bacterium Á Actinobacterium Chromium(Cr) is an important element in industrial processes, i.e. electroplating and leather tanning. However a valence state of Cr, hexavalent Cr (Cr(VI)), is the toxic and harmful chemical form. Therefore it is important to develop technologies for the prevention of Cr(VI) from effusing into natural environment and for the detoxification of Cr(VI) by transforming the valence state into trivalent Cr (Cr(III)). In many bioreduction experiment, the most of Cr(III) was detected in water soluble form but not in insoluble precipitate. It is needed to understand Cr(III) precipitation mechanisms in Cr(VI)-reducing bacteria.Here we describe TEM and EDX analysis of Cr-containing precipitates which were synthesized by newly isolated actinomyces, Flexivirga alba ST13 T (=NBRC 107850 T = DSM 24460 T ) as a model of Cr(III)-accumulating bacterium [1]. The strain reduced Cr(VI) efficiently in minimal medium supplemented with molasses and formed water insoluble Cr(OH) 3 compound [2].Bacteria were grown aerobically in minimal medium (6 g/L Na 2 HPO 4 , 3 g/L KH 2 PO 4 , 1 g/L NH 4 Cl, 0.5 g/L NaCl, 0.246 g/L MgSO 4 Á7H 2 O, 0.01 g/L CaCl 2 , 0.4 % (w/w) molasses; pH 6.8) in a rotating bioshaker (Taitec, Saitama, Japan) at 200 rpm at 27°C. For the preparation of Cr(VI)-containing medium, 0.4 mM CrO 3 (Wako, Osaka, Japan) was added to the medium. Hexavalent and total Cr concentration were measured as described previously [2]. Strain ST13 T growth in medium containing CrO 3 was centrifuged (5,4009g, 5 min) to separate the culture supernatant and the cell pellet. The supernatant was used for Cr(VI) measurement. Briefly, 1 mM diphenylcarbazide (Wako) in 1.2 N H 2 SO 4 was mixed with an equal volume of supernatant for 10 min. The absorbance at 540 nm was determined using a spectrophotometer 3100 (GE Healthcare, Buckinghamshire, England). The Cr(VI) concentration in the sample was estimated by a standard curve generated with known amounts of Cr(VI). About 48 and 5 % Cr(VI) remained in medium on days 5 and 13, respectively. To examine the effect of Cr(VI) on bacterial morphology, gram staining was performed using Fiber-G (Nissui Pharmaceutical Co., Tokyo, Japan) and observed

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Reduction of hexavalent chromium by Pannonibacter phragmitetus LSSE-09 coated with polyethylenimine-functionalized magnetic nanoparticles under alkaline conditions

Cited by 43 publications

References 46 publications

Insight into Serum Protein Interactions with Functionalized Magnetic Nanoparticles in Biological Media

Insight into Serum Protein Interactions with Functionalized Magnetic Nanoparticles in Biological Media

Effect of magnetic field on surface properties ofBacillus cereusCrA and its Extracellular Polymeric Substances (EPS)

Electron Microscopy and X-ray Analysis of Cr-Containing Precipitates Synthesized by Newly Isolated Actinobacterium, Flexivirga alba ST13T

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