Lignin peroxidases of some indigenous ligninolytic fungi: secretion and enzymatic characteristics

摘要

Secretion and enzymatic characteristics of lignin peroxidases from Gloeophyllum sepiarium MTCC 1170, Cladosporium herbarum MTCC 346, Lenzites betulina MTCC 1183, Daedalea flavida MTCC 145, Hexagonia teruis MTCC 1119 and Coirolopsis floccosa MTCC 1177 ligninolytic fungal strains have been reported. Secretion of lignin peroxidase by these ligninolytic fungal strains have been found to be in the range of 0.86 to 3.0 enzyme unit per ml of the culture medium. The enzymatic characteristics like K_m, pH and temperature optima of all the lignin peroxidases of the above fungal strains have been determined using veratryl alcohol and H_2O_2 as the variable substrates. The K_m values using veratryl alcohol as the substrate were found to be 65.0 μM, 58.5 μM, 63.0 μM, 54.5 μM, 54.6 μM and 61.0 μM respectively. The K_m values using H_2O_2 as the substrate were found to be 88.0 μM, 86.0 μM, 71.0 μM, 67.0 μM, 80.0 μM and 78.0 μM respectively. The pH optima values for lignin peroxidases of the above ligninolytic fungal strains were found to be 2.5, 2.4, 2.4, 2.25, 2.5 and 2.8 respectively, where as the temperature optima values were 25°C, 24°C, 25°C, 23°C, 24°C and 25°C respectively.