Purification and characterization of versatile peroxidase from Lentinus squarrosulus and its application in biodegradation of lignocellulosics

Abstract

Versatile Peroxidases are high redox potential peroxidases capable of degrading lignin of lignocellulosic crop residues. Hence Versatile Peroxidases are prominent biocatalysts in upgrading lignocellulosic biomass for biotechnological applications. In the interest of exploiting the potential of Versatile Peroxidase in improving the digestibility of crop residues through delignification, a novel Versatile Peroxidase was purified and characterized from the immobilized cultures of native isolate Lentinus squarrosulus. The enzyme was purified with a specific activity of 62 U/mg through ion exchange and gel filtration chromatographic procedures. The enzyme possessed high affinity towards RB5 and manganese with a Km value of 6.84 µM for RB5 and 0.15 mM for manganese. The optimum temperature for oxidation was identified to be 30°C and optimum pH for manganese and RB5 oxidation was 5 and 3 respectively. Reactivity of the enzyme towards diverse substrates was investigated besides studying the effect of metal ions and inhibitors on RB5 oxidation. The enhanced potential of this purified Versatile Peroxidase in biodegradation of crop residues was demonstrated through augmentation of digestibility of finger millet and paddy straws by 20%.The results demonstrated that Versatile Peroxidase from Lentinus squarrosulus is capable of enhancing the nutritive value of crop residues through delignification