ABTS-Modified Silica Nanoparticles as Laccase Mediators for Decolorization of Indigo Carmine Dye

Abstract EN

Efficient reuse and regeneration of spent mediators are highly desired for many of the laccases’ biotechnology applications.

This investigation demonstrates that a redox mediator 2,2′-azino-bis-(3-ethylbenzothiazoline)-6-sulfonic acid (ABTS) covalently attached to silica nanoparticles (SNPs) effectively mediated dye decolorization catalyzed by laccase.

Characteristics of ABTS-modified silica nanoparticles (ABTS-SNPs) were researched by scanning electron microscopy and Fourier-transformed infrared spectroscopy.

When ABTS and ABTS-SNPs were used as laccase mediators, the decolorization yields of 96 and 95% were, respectively, obtained for indigo carmine dye.

The results suggest that ABTS immobilized on SNPs can be used as laccase mediators as they retain almost the same efficiency as the free ABTS.

The oxidized ABTS-SNPs were regenerated by their reduction reaction with ascorbic acid.

Decolorization efficiency of regenerated ABTS-SNPs and their initial forms were found to be almost equivalent.

Six reuse cycles for spent ABTS-SNPs were run for the treatment of indigo carmine, providing decolorization yields of 96–77%.

Compared with free mediator, the immobilized mediators have the advantage of being easily recovered, regenerated, and reused making the whole process environmentally friendly.