Immobilization of laccase in alginate-gelatin mixed gel and decolorization of synthetic dyes.

Mehdi Mogharabi,Nastaran Nafissi-Varcheh,Nasser Nassiri-Koopaei,Mohammad Ali Faramarzi,Ghodsieh Bagherzadeh,Maryam Bozorgi-Koushalshahi

doi:10.1155/2012/823830

Abstract

Alginate-gelatin mixed gel was applied to immobilized laccase for decolorization of some synthetic dyes including crystal violet. The immobilization procedure was accomplished by adding alginate to a gelatin solution containing the enzyme and the subsequent dropwise addition of the mixture into a stirred CaCl2 solution. The obtained data showed that both immobilized and free enzymes acted optimally at 50°C for removal of crystal violet, but the entrapped enzyme showed higher thermal stability compared to the free enzyme. The immobilized enzyme represented optimum decolorization at pH 8. Reusability of the entrapped laccase was also studied and the results showed that ca. 85% activity was retained after five successive cycles. The best removal condition was applied for decolorization of seven other synthetic dyes. Results showed that the maximum and minimum dye removal was related to amido black 10B and eosin, respectively.

Highlights

While traditional methods in chemical processes have improved in the last decades, extensive attention has been paid to alternative techniques that utilize enzymes involving excellent characteristics, such as high activity, selectivity, and specificity
The obtained data showed that both immobilized and free enzymes acted optimally at 50◦C for removal of crystal violet, but the entrapped enzyme showed higher thermal stability compared to the free enzyme
The aim of the present study was to apply alginategelatin mixed gel to immobilize laccase, which is further employed in the decolorization of some synthetic dyes, such as crystal violet, in aqueous solutions

Summary

Introduction

While traditional methods in chemical processes have improved in the last decades, extensive attention has been paid to alternative techniques that utilize enzymes involving excellent characteristics, such as high activity, selectivity, and specificity. Enzymes action at mild conditions of pH, pressure, and temperature proposes them as candidates for suitable catalysts in industries where low cost, energy savings, and simplicity are important [1, 2]. Despite these advantages, some practical problems restrict their use, such as the high-cost isolation and purification process and instability in organic media and high temperatures. To overcome these limitations, several methods have been suggested and the most important of which are immobilization techniques [3, 4]. Single-step immobilization is one of the most frequently used methods of entrapment, which

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Conclusion