Abstract:
Lignin Peroxidase (LiP) is one of the key enzymes produced by several ligninolytic fungi including P. chrysosporium for degradation of lignin and several polyaromatic hydrocarbons. Textile azo dyes are also polyaromatic in nature and ligninolytic enzymes have been used for treatment of dye containing wastewaters. Solid state fermentation of wheat straw was attempted with P. chrysosporium MTCC 787 for production of LiP at 39ºC. Fermented residue was extracted with 0.2 M sodium tartarate buffer (pH 3) and was subjected to ammonium sulfate precipitation. Precipitates obtained were subjected to LiP assay, upon dialysis, using veratryl alcohol as substrate. Optimum pH, temperature and H2O2 were reported to be pH 3.5, 30ºC and 0.4 mM, respectively. Km and Vmax of LiP for veratryl alcohol were found to be 0.28 mM and 33.3 U/mg, respectively. Enzyme kinetics were also assessed against Reactive Black B (RBB), a widely used textile diazo dye, as substrate. Km and Vmax for this dye were observed to be 0.2 mM and 7 U/mg, respectively. These findings suggest higher affinity of LiP towards tested dye and hence the enzyme has a great potential in its application for treatment of RBB containing wastewater.
