Abstract
Two extracellular peroxidases from Phanerochaete chrysosporium, namely a lignin peroxidase (Lip) and manganese peroxidase (MnP), were purified simultaneously by applying successively, ultrafiltration, ion-exchange and gel filtration chromatography. LiP and MnP have a molecular mass of 36 and 45 kDa, respectively. The optimal pHs for LiP and MnP activities were 3.0 and 4.5, respectively. Both peroxidases showed maximal activity at 30 degrees C and moderate thermostability: MnP activity was strongly inhibited by Fe2+, Zn2+, Mg2+ and Hg2+, and enhanced by Mn2+, Ca2+ and Cu2+. LiP activity was enhanced by Ca2+, Na+ and Co2+ and it was inhibited in the presence of K+, Hg+, Fe2+, Mg2+ and high concentrations of Cu2+ and Zn2+. The K-m and V-max for LiP toward veratryl alcohol as a substrate were 0.10 mM and 15.2 U mg(-1), respectively and for MnP toward Mn2+, they were respectively 0.03 mM and 25.5 U mg(-1). The two peroxidases were also able to break down rice lignin in a small-scale solid state treatment system. Data suggest these two peroxidases may be considered as potential candidates for the development of enzyme-based technologies for lignin degradation. (C) 2013 Elsevier Ltd. All rights reserved.