Date Published: February 4, 2016
Publisher: Springer Berlin Heidelberg
Author(s): Dalel Daâssi, Héla Zouari-Mechichi, Lassaad Belbahri, Jorge Barriuso, María Jesús Martínez, Moncef Nasri, Tahar Mechichi.
In this study, 51 fungal strains were isolated from decaying wood samples collected from forests located in the Northwest of Tunisia in the vicinity of Bousalem, Ain Draham and Kef. Phylogenetic analysis based on the sequences of the internal transcribed spacers of the ribosomal DNA showed a high diversity among the 51 fungal isolates collection. Representatives of 25 genera and 29 species were identified, most of which were members of one of the following phyla (Ascomycota, Basidiomycota and Zygomycota). In addition to the phylogenetic diversity, a high diversity of secreted enzyme profiles was also detected among the fungal isolates. All fungal strains produced at least one of the following enzymes: laccase, cellulase, protease and/or lipase.
Wood is the most abundant biopolymer in nature and is made up mainly of cellulose, hemicellulose, and lignin. The lignin polymer is highly recalcitrant toward chemical and biological degradation due to its molecular architecture, where different non-phenolic phenylpropanoid units forming a complex three-dimensional network, are interconnected by a variety of ether and carbon–carbon bonds. Its biodegradation is a key step for carbon recycling in terrestrial ecosystems.
Our findings contribute to the discovery of new fungal strains involved in lignocellulose degradation. The isolated strains are diverse and show a wide spectrum of species demonstrating the wide biodiversity of Tunisian forests. The newly isolated fungal strains belong to different taxonomic groups with various enzymatic activities: amylases, proteases, lipases and laccases, making their further study very interesting for industrial and environmental applications. Our results show that this new collection of isolates had a certain lignin degradation capacity and provide a new resource of microorganisms for dye decolorization.