Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
11026088 | International Journal of Biological Macromolecules | 2018 | 44 Pages |
Abstract
A laccase-producing ascomycete was isolated from arid soil in Tunisia. This fungus was identified as Thielavia sp. using the phylogenetic analysis of rDNA internal transcribed spacers. The extracellular laccase produced by the fungus was purified to electrophoretic homogeneity, showing a molecular mass around 70â¯kDa. The enzyme had an optimum pH of 5.0 and 6.0 for ABTS and 2,6âDMP, respectively and it showed remarkable high thermal stability, showing its optimal temperature at 70â¯Â°C (against 2,6âDMP). It presented slight inhibiting effect by EDTA, SDS and lâcyst although this effect was more marked by sodium azide (0.1â¯mM). On the other hand, it showed tolerance to up to 300â¯mM NaCl, retaining around 50% of its activity at 900â¯mM. Among the metal ions tested on TaLac1, Mn2+ showed an activating effect. Their kinetic parameters Km and kcat were 23.7â¯Î¼M and 4.14â¯sâ1 for ABTS, and 24.3â¯Î¼M and 3.46â¯sâ1 towards 2,6âDMP. The purified enzyme displayed greater efficiency in Remazol Brilliant Blue R decolorization (90%) in absence of redox mediator, an important property for biotechnological applications.
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Authors
Rim Mtibaà , Jorge Barriuso, Laura de Eugenio, Elisabet Aranda, Lasaad Belbahri, Moncef Nasri, MarÃa Jesùs MartÃnez, Tahar Mechichi,