Elsevier

Chemosphere

Volume 83, Issue 3, April 2011, Pages 255-264
Chemosphere

Hemoglobin (Hb) immobilized on amino-modified magnetic nanoparticles for the catalytic removal of bisphenol A

https://doi.org/10.1016/j.chemosphere.2010.12.075Get rights and content

Abstract

Catalytic removal of bisphenol A from aqueous solution with hemoglobin immobilized on amino-modified magnetic nanoparticles as an enzyme catalyst was reported. The amino-modified magnetite nanoparticles were firstly prepared by the coprecipitation of Fe2+ and Fe3+ with NH3·H2O and then modified by 3-aminopropyltriethoxysilane. The immobilization process was optimized by examining enzyme concentration, glutaraldehyde concentration, cross-link time, and immobilization time. The optimum conditions for the removal of bisphenol A with immobilized hemoglobin were also investigated. Under the optimality conditions, the removal efficiency of bisphenol A was about 80.3%. The immobilization had a beneficial effect on the stability of hemoglobin and conversions of bisphenol A. According to the proposed breakdown pathway and the intermediates, the enzyme-catalytic removal of bisphenol A by the immobilized hemoglobin is considered to be an effective method.

Research highlights

► Fe3O4 were prepared by co-precipitation and modified by APTS to form amino-Fe3O4. ► Fe3O4 and amino-Fe3O4 were characterized by FT-IR, XRD, TEM. ► The Hb immobilization and the removal of BPA with immobilized Hb were optimized. ► Possible mechanism was proposed according to LC–MS analysis.

Introduction

Bisphenol A [BPA, 2,2-bis(4-hydroxyphenyl)propane] is made by combining acetone with phenol, and it is widely used as a material for the production of epoxy resins, phenol resins, polycarbonates, polyacrylates, polyesters, and lacquer coatings on food cans (Kang and Kondo, 2005). Recently, BPA has received a great deal of attention from regulatory agencies and scientists, because it has estrogenic activity and serves as an environmental endocrine disruptor (Chen et al., 2006). Hence, it is essential to develop efficient treatment methodology for the removal of BPA in wastewater. Conventional wastewater treatment methods like chemical precipitation, activated carbon adsorption and ion exchange are usually effective in the removal of these phenolic compounds (Gupta et al., 2004, Jain et al., 2004). However, they transfer the contaminants from one medium to another and hence further treatment is required. For these instances, a rapid, simple and economic wastewater treatment for the removal of BPA is now highly in demand.

Many enzymatic-catalyzed methods based on the peroxide enzymes to degrade BPA with the help of H2O2 reduction have been investigated and reported (Yamada et al., 2010). Horseradish peroxidase (HRP), in which the heme iron acts as the active center, has been used in the catalyzed oxidation of BPA (Li and James, 2008, Li et al., 2008). Moreover, the tyrosinase was also reported to be used for removal of BPA through the tyrosinase-catalyzed quinone oxidation and subsequent nonenzymatic quinone adsorption on chitosan beads (Suzuki et al., 2010). However, these native enzymes are expensive and relatively short lived in environment. Therefore, more and more researchers used the stable and cheap mimetic enzymes such as hematin (Li and Dasgupta, 2000), hemin (Wang et al., 1999) and the porphyrin complexes of Mn, Co, Fe and Mo (Kawamura-Konishi et al., 1998) to replace the native enzyme. Nevertheless, these simple natural or synthetic metalloporphyrins, lacking the spatial structure of the natural enzyme for the special inclusion behavior between the enzyme and the substrate, do not show satisfactory activity and selectivity (Yu and Ju, 2003). For these instances, many scientists turned their attention to heme proteins. Some heme proteins, e.g., hemoglobin, myoglobin, etc., were reported to be involved in dehalogenation of organic halides (Li et al., 2006).

Hemoglobin (Hb), which is an important respiratory heme protein in red cells, plays an important role in carrying oxygen in the blood of vertebrate animals. As a member of the large class of heme proteins, Hb has long been as a representative system for investigation the structure, dynamic, and thermodynamic properties of enzymes, especially in understanding the biological behaviors of the catalyzed oxidation of substrates by H2O2 (Jian et al., 2007). Hence, numerous researches were focused on the H2O2 biosensors constructed with Hb due to its easy availability in high purity and low cost (Yin et al., 2006, Qi et al., 2006, Kafi et al., 2006). Hb is not a real peroxidase as HRP but a hemoprotein with some pseudoperoxidase activity (Phuoc et al., 2010). To the best of our knowledge, some investigations for enzymatic oxidation of organic contaminants such as Polycyclic Aromatic Hydrocarbons (PAH) by using Hb were reported (Phuoc et al., 2010, Laveille et al., 2010). In our previous work, we have investigated and reported the degradation of BPA in water catalyzed by Hb in an electrochemical reactor; the removal efficiency reached 50.7% under optimal operation conditions in 120 min (Tang et al., 2010).

Soluble enzyme is difficult to separate from the reaction system; therefore, it could not be reuse in the practical applications (Gaur et al., 2006). Such drawbacks may be overcome by using immobilized enzyme as biocatalysts that can be easily removed from the reaction medium (Gómez et al., 2006, Pan et al., 2009). In recent years, magnetic microspheres were used for the immobilization of enzymes (Arica et al., 2000, Peniche et al., 2005, Hong et al., 2007). The use of magnetic nanoparticles as supports for enzyme immobilization is endowed with the following advantages: (1) higher specific surface favors the binding efficiency, (2) lower mass transfer resistance and less fouling, (3) the selective separation of immobilized enzymes under a magnetic field and hence lower operation cost, and (4) the application of a continuous biocatalysis system (Tong et al., 2001, Guo and Sun, 2004, Deng et al., 2003). It was reported that magnetic microspheres could be used for the immobilization of Hb through adsorption (Sevilla et al., 2009) or suspension crosslinking technique (Lai et al., 2008). As far as we know, there are no reports for BPA degradation using Hb immobilized on magnetic microspheres as an enzymatic catalyst.

In this report, 3-aminopropyltriethoxysilane coated magnetic nanoparticles were synthesized by coating 3-aminopropyltriethoxysilane onto the Fe3O4 nanoparticles, due to the abundant amino groups and excellent biocompatibility of 3-aminopropyltriethoxysilane, the enzyme Hb could be immobilized onto the amino-coated magnetic nanoparticles. The applications of the immobilized Hb for enzyme-catalyzed removal of BPA from aqueous solution were investigated.

Section snippets

Materials

Hemoglobin (Hb) from bovine blood (MW, 64 500) was obtained from Beijing Biodee Biotechnology Company Ltd (China). Bisphenol A (BPA) and 4-aminoantipyrine (4-AAP) and other chemicals were obtained from Shanghai Jingchun Reagent Company (China). All of the chemicals were of analytical reagent grade and used as received without further purification.

Synthesis and characterization of magnetite nanoparticles

The synthesis and immobilization steps were illustrated by Scheme 1. Fe3O4 nanoparticles were prepared by co-precipitating of Fe2+ (FeSO4·7H2O) and Fe3+

Characterization of APTS-coated magnetic nanoparticles

Fig. 1A shows the FT-IR spectra of the naked Fe3O4 (a) and APTS-Fe3O4 nanoparticles (b). The characteristic absorption peak for Fe3O4 was observed at 580 cm−1 (Fe–O). O–H stretching vibration about 3440 cm−1 and O–H deformed vibration at 1644 cm−1 were observed both in Fig. 1A (a) and (b), suggesting that –OH groups coat on the surface of Fe3O4 nanoparticles as reported (Xie and Ma, 2009, Kim et al., 2001). Consequently, it was inferred that the APTS could be immobilized directly on the surface of

Conclusion

In summary, we have demonstrated the successful immobilization of Hb onto APTS-coated Fe3O4 nanoparticles. The optimal conditions for Hb immobilization were dependent on the concentration of enzyme, the concentration of glutarahyde, cross-link time, and immobilization time. The immobilized Hb showed the same or even higher activity in wider ranges of temperature and pH than that of its free form. After being immobilized on the support, the Hb exhibited good thermo stability and storage

Acknowledgement

This work was supported by the National Natural Science Foundation of China (No. 21075078).

References (55)

  • F. Jian et al.

    Direct electrochemistry of hemoglobin in TATP film: Application in biological sensor

    Sens. Actuators, B

    (2007)
  • A.K.M. Kafi et al.

    Hydrogen peroxide biosensor based on DNA-Hb modified gold electrode

    Thin Solid Films

    (2006)
  • J.H. Kang et al.

    Bisphenol A degradation in seawater is different from that in river water

    Chemosphere

    (2005)
  • Y. Kawamura-Konishi et al.

    Peroxidase activity of an antibody-ferric porphyrin complex

    J. Mol. Catal. B: Enzyme

    (1998)
  • D.K. Kim et al.

    Characterization and MRI study of surfactant-coated superparamagnetic nanoparticles administered into the rat brain

    J. Magn. Magn. Mater.

    (2001)
  • G.S. Lai et al.

    A novel hydrogen peroxide biosensor based on hemoglobin immobilized on magnetic chitosan microspheres modified electrode

    Sens. Actuators, B

    (2008)
  • Y.C. Lai et al.

    Application of immobilized horseradish peroxidase for the removal of p-chlorophenol from aqueous solution

    Process Biochem.

    (2005)
  • T. Li et al.

    Immobilization and stabilization of pectinase by multipoint attachment onto an activated agar-gel support

    Food Chem.

    (2008)
  • Y.P. Li et al.

    Electrochemical dechlorination of chloroacetic acids (CAAs) using hemoglobin-loaded carbon nanotube electrode

    Chemosphere

    (2006)
  • F. López-Gallego et al.

    Preparation of a robust biocatalyst of d-amino acid oxidase on sepabeads supports using the glutaraldehyde crosslinking method

    Enzyme Microb. Technol.

    (2005)
  • F. López-Gallego et al.

    Enzyme stabilization by glutaraldehyde crosslinking of adsorbed proteins on aminated supports

    J. Biotechnol.

    (2005)
  • M. Ma et al.

    Preparation and characterization of magnetite nanoparticles coated by amino silane

    Colloids Surf. A

    (2003)
  • C. Mateo et al.

    Improvement of enzyme activity, stability and selectivity via immobilization techniques

    Enzyme Microb. Technol.

    (2007)
  • J. Michizoe et al.

    Biodegradation of phenolic environmental pollutants by a surfactant-laccase complex in organic media

    J. Biosci. Bioeng.

    (2005)
  • M. Monier et al.

    Immobilization of horseradish peroxidase on modified chitosan beads

    Int. J. Biol. Macromol.

    (2010)
  • C. Pan et al.

    Novel and efficient method for immobilization and stabilization of β-D-galactosidase by covalent attachment onto magnetic Fe3O4-chitosan nanoparticles

    J. Mol. Catal. B: Enzyme

    (2009)
  • H.L. Qi et al.

    Amperometric third-generation hydrogen peroxide biosensor incorporating multiwall carbon nanotubes and hemoglobin

    Sens. Actuators, B

    (2006)
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