Screening of Novel Ascomycetes for the Production of Laccase Enzyme Using Different Lignin Model Compounds

The objective of this present study was to isolate a potential laccase producing fungi from the different environmental samples from Gujarat. Eighteen morphologically different fungi were isolated on mineral salts medium having lignin (sole carbon source) and screened qualitatively for their ability to produce laccase by plate screening method using the indicators ABTS, Brilliant Blue R (RBBR), Syringaldazine and Guaicol. Six selected fungal isolates were further screened quantitatively in liquid medium and assayed using ABTS as a substrate. The highest laccase productivity in liquid medium was 166.2 U/ml (3 rd day) with BL-21/4. The genotypic characterization of selected fungal isolates was performed with partial 18S rRNA sequencing using ITS primer set ITS1/ITS4. The fungal isolates were identified as Aspergillus versicolor, Curvularia aeria, Curvularia lunata and Curvularia akaii. The conclusions of this study confirm that ABTS and Syringaldazine is very efficient phenolic compound for qualitative screening of novel ascomycetes that produces laccase.