title: Dye decolorization and detoxification potential of Ca-alginate beads immobilized manganese peroxidase.
abstract: BACKGROUND
  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. 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).
  
  
  RESULTS
  MnP 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 K(m) and V(max) 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.
  
  
  CONCLUSIONS
  G. 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.
authors.affiliation: Industrial Biotechnology Laboratory, Department of Biochemistry, University of Agriculture, Faisalabad, Pakistan. bilaluaf@hotmail.com.
authors.forename: Muhammad
authors.initials: M
authors.lastname: Bilal
authors.affiliation: Industrial Biotechnology Laboratory, Department of Biochemistry, University of Agriculture, Faisalabad, Pakistan. mabajwapk@yahoo.com.
authors.forename: Muhammad
authors.initials: M
authors.lastname: Asgher
mesh_terms: D000464:Alginates / Q000737:chemistry*; D001673:Biodegradation, Environmental; D002122:Calcium Chloride / Q000737:chemistry; D004396:Coloring Agents / Q000737:chemistry* / Q000633:toxicity; D004795:Enzyme Stability; D004800:Enzymes, Immobilized / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D020723:Glucuronic Acid / Q000737:chemistry; D006603:Hexuronic Acids / Q000737:chemistry; D007218:Industrial Microbiology; D008031:Lignin / Q000737:chemistry; D010544:Peroxidases / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D020940:Reishi / Q000201:enzymology; D013783:Textile Industry; D014865:Waste Disposal, Fluid
chemical_list: D000464:Alginates; D004396:Coloring Agents; D004800:Enzymes, Immobilized; D006603:Hexuronic Acids; C036909:lignocellulose; D020723:Glucuronic Acid; D008031:Lignin; D010544:Peroxidases; C051129:manganese peroxidase; D002122:Calcium Chloride