Dye decolorization and detoxification potential of Ca-alginate beads immobilized manganese peroxidase.

Muhammad Bilal,Muhammad Asgher

doi:10.1186/s12896-015-0227-8

Abstract

BackgroundIn view of compliance with increasingly stringent environmental legislation, an eco-friendly treatment technology of industrial dyes and effluents is a major environmental challenge in the color industry. In present study, a promising and eco‐friendly entrapment approach was adopted to immobilize purified manganese peroxidase (MnP) produced from an indigenous strain of Ganoderma lucidum IBL-05 on Ca-alginate beads. The immobilized MnP was subsequently used for enhanced decolorization and detoxification of textile reactive dyes).ResultsMnP isolated from solid-state culture of G. lucidum IBL-05, presented highest immobilization yield (83.9 %) using alginate beads prepared at optimized conditions of 4 % (w/v) sodium alginate, 2 % (w/v) Calcium chloride (CaCl2) and 0.5 mg/ml enzyme concentration. Immobilization of MnP enhanced optimum temperature but caused acidic shift in optimum pH of the enzyme. The immobilized MnP showed optimum activity at pH 4.0 and 60 °C as compared to pH 5.0 and 35 °C for free enzyme. The kinetic parameters Km and Vmax of MnP were significantly improved by immobilization. The enhanced catalytic potential of immobilized MnP led to 87.5 %, 82.1 %, 89.4 %, 95.7 % and 83 % decolorization of Sandal-fix Red C4BLN, Sandal-fix Turq Blue GWF, Sandal-fix Foron Blue E2BLN, Sandal-fix Black CKF and Sandal-fix Golden Yellow CRL dyes, respectively. The insolubilized MnP was reusable for 7 repeated cycles in dye color removal. Furthermore, immobilized MnP also caused a significant reduction in biochemical oxygen demand (BOD) (94.61-95.47 %), chemical oxygen demand (COD) (91.18-94.85 %), and total organic carbon (TOC) (89.58-95 %) of aqueous dye solutions.ConclusionsG. lucidum MnP was immobilized in Ca-alginate beads by entrapment method to improve its practical effectiveness. Ca-alginate bound MnP was catalytically more vigorous, thermo-stable, reusable and worked over wider ranges of pH and temperature as compared to its free counterpart. Results of cytotoxicity like hemolytic and brine shrimp lethality tests suggested that Ca-alginate immobilized MnP may effectively be used for detoxification of dyes and industrial effluents.

Highlights

In view of compliance with increasingly stringent environmental legislation, an eco-friendly treatment technology of industrial dyes and effluents is a major environmental challenge in the color industry
Triton X-100 and cyclophosphamide were purchased from Merck (Germany) and Scharlau (Spain), respectively
All chemicals and reagents were of analytical grade and used without further purification

Summary

Introduction

In view of compliance with increasingly stringent environmental legislation, an eco-friendly treatment technology of industrial dyes and effluents is a major environmental challenge in the color industry. Bilal and Asgher BMC Biotechnology (2015) 15:111 for large-scale effluent treatment [5, 7] These facts certainly demand the development of an efficient, cost effective and green technology for decolorization and detoxification of dyes and industrial effluents. Among the potential applications of MnP are bioremediation, biomass delignification, biopulping, biosensor development, textile finishing and wine stabilization [2, 11]. Despite their great potential, the use of native microbial enzymes suffers certain restrictions under industrial process conditions. The use of native microbial enzymes suffers certain restrictions under industrial process conditions To circumvent these limitations, several strategies including mutations, genetic engineering, chemical modifications of amino acid residues and immobilization have been suggested. Enzyme immobilization appears to be an attractive approach to develop efficient biocatalyst with improved performances such as enhanced resistance to thermal and chemical inactivation, remarkable storage and operational stabilities, short response time and high reproducibility [12, 13]

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Results

Conclusion