Isolation and Screening of Lignolytic Fungi from Various Ecological Niches

摘要

Lignin is a major noncarbohydrate polyphenolic structural constituent of cell wall of all the vascular plants and is present in association with cellulose and hemicellulose. It is the second most abundant polymer after cellulose. Lignin is well known for its resistance to microbial degradation because of its high molecular weight and various biologically stable carbon-carbon and ether linkages. Seventy two fungal isolates capable of utilizing lignocellulosic biomass were isolated from different ecological samples. When subjected to primary screening by qualitative plate assay method using methyl orange, azure B, guaiacol and tannic acid as indicators for determining the lignolytic potential, 22 isolates were found positive for at least one of the indicators. Six isolates were found to exhibit all the three extracellular enzyme activities on quantitative estimation of laccase, manganese peroxidase and lignin peroxidase activities. Highest laccase activity was produced by ANF238 (3.42U/ml) while highest manganese peroxidase and lignin peroxidase activities were produced by ANF 212 (0.254U/ml) and ANF238 (0.22U/ml) respectively.