Characterization of Laccase Enzyme from Dye Degrading Bacterial Strains Isolated from Natural Sources

Abstract

The continuous growth in globalization and industrialization has increased the environmental pollution and one such major contaminant is various types of synthetic dyes. Microbial decolorization and degradation of these dyes through secretion of various extracellular enzymes is gaining importance owing to their eco-friendly nature. One such enzyme is laccase, a multicopper oxidase enzyme which has the ability to oxidize both phenolic and non-phenolic compounds through reduction of molecular oxygen to water. In this study, laccase enzyme has been characterized from two bacterial species of Klebsiella and Enterobacter; isolated from industrial waste polluted Ganges water. An in vivo assay of the extracellular laccase enzyme was performed at different time-points using guaiacol as substrate and copper as an inducer, both being added in the growth medium. For both the species, the enzyme production continued till late 288 hours and the optimal pH and temperature of the enzyme activity was found to be 7.5 and 37°C respectively. The enzyme activity was found to be inhibited by EDTA and NaCl. For enzyme–kinetics study, an in vitro assay using syringaldazine as substrate was performed; the K_m of the G5-laccase enzyme was determined to be 0.66 mM and 0.74 mM for R5 laccase. The V_max was found to be 30.76 U/ml for strain G5 and 26.78 U/ml for strain R5.

Keywords: Laccase, guaiacol, malachite green, syringaldazine, Ganges water

Cite this Article

Suchismita Das, Anamika Ghatak. Characterization of Laccase Enzyme from Dye Degrading Bacterial Strains Isolated from Natural Sources. Research & Reviews: A Journal of Microbiology and Virology. 2019; 9(1): 65–76p.