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Ionic polymer-coated laccase with high activity and enhanced stability: application in the decolourisation of water containing AO7.

Zhang X, Hua M, Lv L, Pan B - Sci Rep (2015)

Bottom Line: The stability of the resulting LacPG was highly enhanced against pH variations, thermal treatments and provided better long-term storage with a negligible loss in enzymatic activity.Compared to Lac, LacPG exhibited significantly higher decolourisation efficiency in the degradation of a representative azo dye, acid orange 7 (AO7), which resulted from the electrostatic attraction between the coating and AO7.The increased size and modified surface chemistry of LacPG facilitated ultrafiltration and reduced membrane fouling.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, P.R. China.

ABSTRACT
Eliminating dyes in environmental water purification remains a formidable challenge. Laccase is a unique, environmentally friendly and efficient biocatalyst that can degrade pollutants. However, the use of laccase for the degradation of pollutants is considerably limited by its susceptibility to environmental changes and its poor reusability. We fabricated a novel biocatalyst (LacPG) by coating polyethylenimine onto the native laccase (Lac) followed by crosslinking with glutaraldehyde. The stability of the resulting LacPG was highly enhanced against pH variations, thermal treatments and provided better long-term storage with a negligible loss in enzymatic activity. Compared to Lac, LacPG exhibited significantly higher decolourisation efficiency in the degradation of a representative azo dye, acid orange 7 (AO7), which resulted from the electrostatic attraction between the coating and AO7. LacPG was separated from the AO7 solution using an ultrafiltration unit. The increased size and modified surface chemistry of LacPG facilitated ultrafiltration and reduced membrane fouling. LacPG exhibited enhanced stability, high catalytic activity and favourable properties for membrane separation; therefore, LacPG could be continuously reused in an enzymatic membrane reactor with a high efficiency for decolourising water containing AO7. The developed strategy appears to be promising for enhancing the applicability of laccase in practical water treatment.

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Potential role of PEI coatings on LacPG decolourisation of (a) AO7 and (b) MG.
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f8: Potential role of PEI coatings on LacPG decolourisation of (a) AO7 and (b) MG.

Mentions: Figure 8 shows that the PEI coating created a new surface chemistry for LacPG: the LacPG surface was positively charged at pH 5, whereas the Lac surface was negatively charged at this pH. Thus, the electrostatic attraction would cause anionic AO7 molecules to concentrate near the surface of the positively charged LacPG. Similarly, a lower concentration of cationic MG was expected near the LacPG surface than in the bulk solution. The dye concentration distribution near the LacPG surface affected the ability of LacPG to degrade the targeted dyes.


Ionic polymer-coated laccase with high activity and enhanced stability: application in the decolourisation of water containing AO7.

Zhang X, Hua M, Lv L, Pan B - Sci Rep (2015)

Potential role of PEI coatings on LacPG decolourisation of (a) AO7 and (b) MG.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4317704&req=5

f8: Potential role of PEI coatings on LacPG decolourisation of (a) AO7 and (b) MG.
Mentions: Figure 8 shows that the PEI coating created a new surface chemistry for LacPG: the LacPG surface was positively charged at pH 5, whereas the Lac surface was negatively charged at this pH. Thus, the electrostatic attraction would cause anionic AO7 molecules to concentrate near the surface of the positively charged LacPG. Similarly, a lower concentration of cationic MG was expected near the LacPG surface than in the bulk solution. The dye concentration distribution near the LacPG surface affected the ability of LacPG to degrade the targeted dyes.

Bottom Line: The stability of the resulting LacPG was highly enhanced against pH variations, thermal treatments and provided better long-term storage with a negligible loss in enzymatic activity.Compared to Lac, LacPG exhibited significantly higher decolourisation efficiency in the degradation of a representative azo dye, acid orange 7 (AO7), which resulted from the electrostatic attraction between the coating and AO7.The increased size and modified surface chemistry of LacPG facilitated ultrafiltration and reduced membrane fouling.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, P.R. China.

ABSTRACT
Eliminating dyes in environmental water purification remains a formidable challenge. Laccase is a unique, environmentally friendly and efficient biocatalyst that can degrade pollutants. However, the use of laccase for the degradation of pollutants is considerably limited by its susceptibility to environmental changes and its poor reusability. We fabricated a novel biocatalyst (LacPG) by coating polyethylenimine onto the native laccase (Lac) followed by crosslinking with glutaraldehyde. The stability of the resulting LacPG was highly enhanced against pH variations, thermal treatments and provided better long-term storage with a negligible loss in enzymatic activity. Compared to Lac, LacPG exhibited significantly higher decolourisation efficiency in the degradation of a representative azo dye, acid orange 7 (AO7), which resulted from the electrostatic attraction between the coating and AO7. LacPG was separated from the AO7 solution using an ultrafiltration unit. The increased size and modified surface chemistry of LacPG facilitated ultrafiltration and reduced membrane fouling. LacPG exhibited enhanced stability, high catalytic activity and favourable properties for membrane separation; therefore, LacPG could be continuously reused in an enzymatic membrane reactor with a high efficiency for decolourising water containing AO7. The developed strategy appears to be promising for enhancing the applicability of laccase in practical water treatment.

Show MeSH
Related in: MedlinePlus