Immobilized lignin peroxidase from Ganoderma lucidum IBL-05 with improved dye decolorization and cytotoxicity reduction properties

Use of free microbial enzymes for bioremediation and other industrial applications has several disadvantages like low stability and non-reusability in repeated batch operations. Immobilized enzymes are stable, recoverable and reusable in industrial processes. In this scenario G. lucidum IBL-05 LiP was entrapped in Ca-alginate beads using optimum concentrations of Na-alginate (4%), calcium chloride (0.2 M) and glutraldehyde (0.02%). Optimum pH (pH 5) and temperature (55 °C) for entrapped LiP were improved as compared to free LiP. Catalytic behavior of LiP also significantly enhanced, as Km value (0.25 mM) decreased and Vmax value (868.6 μmol/min) increased after ca-alginate entrapment of LiP. Decolorization efficiencies of Sandal reactive dyes after treating with immobilized LiP were in the range of 80-93%. A significant reduction was observed in water quality parameters including, BOD (66.44-98.22%), COD (81.34-98.82%) and TOC (80.21-97.77%) values. The cytotoxicity values for heamolytic and brine shrimp lethality of dye solutions treated with Ca-alginate immobilized LiP reduced up to 2.10-5.06% and 5.43-9.23%, respectively. On the basis of reduced toxicity and cytotoxicity values, it was concluded that Ca-alginate beads entrapped LiP may be an effective biocatalyst for bioremediation of dye based textile industry effluents.