Comparison of biopolymers for immobilization of laccase: Ecotoxicity assessment of azo dye

Abstract

Laccase from <i style="mso-bidi-font-style:normal">Pleurotus florida</i> was immobilized on agarose/agar/polyacrylamide gel, glass beads and alginate beads. The laccase entrapped agarose gel exhibited 88% of immobilization yield as compared to laccase immobilization on glass bead (72%) and Ba-alginate (50%). The enzyme embodied in agarose gel showed greater storage stability at 16<span style="mso-bidi-font-family:" times="" new="" roman""="" lang="EN-GB">°C as compared to enzyme immobilized on glass beads and alginate method. Among the three substrates, <i>viz.</i>, 2,2-azinobis (3-ethylbenzo-thiazoline-6-sulfonate (ABTS), guaiacol and syringaldazine, the laccase oxidation exerted its optimal activity on ABTS. The <i style="mso-bidi-font-style:normal">V</i>_max,<i style="mso-bidi-font-style: normal">K</i>_cat<i style="mso-bidi-font-style:normal"> </i>and <i style="mso-bidi-font-style:normal">K</i>_m determined for ABTS were 1.650 µM min⁻¹, 1.160 s⁻¹and 0.0025 mM, respectively. Among the immobilized preparations, laccase entrapped in agarose gel showed high decolorizing ability for Reactive Blue (RB) 172 (83%) within 10 min. The decolorization of RB 172 was confirmed by FTIR analysis. The ecotoxicity assessment of RB 172 decolorization<i style="mso-bidi-font-style:normal"> </i>was performed using <i style="mso-bidi-font-style:normal">Allium cepa </i>assay.

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