Search

In order to evaluate their potential to be used as charcoal production by a new industrial thermal treatment process; the wood of seven trees of introduced species in the North eastern Tunisia (3 Eucalyptus, 4 Casuarina) and 1 local species (Tetraclinis) were selected. Physical properties of natural woods and Gravimetric yields in charcoal, ultimate composition, heating values measurements and combustion quality tests were performed before and after carbonization process. For the same thermal degradation intensity (550 °C—4 h), Gravimetric yields in charcoal values were comprised between 41.1 and 45.3.9% for Casuarina wood species, 35.5 and 39.4% for Eucalyptus wood species and was 33.7% for Tetraclinis articulata wood. Elemental composition showed a significant difference between the selected species. It varies from 1.46 to 1.65 for H/C and 0.67 to 0.77 for O/C. Casuarina wood species showed the lowest values for the both ratios. The calorific values showed that the selected wood species have Heating Values ranged from 16.264to 20.798 MJ/kg and allow producing charcoal with heating values comprised between 23.871 and 30.943 MJ/kg. The best energetic improvement by carbonization process, in this work, concerns Eucalyptus and Tetraclinis woods, except for the Eucalyptus salmonophloia but the combustion quality showed that Casuarina wood species appears to be the wood species with the most optimal combustion, after undergoing a carbonization process.

Major intrinsic proteins (MIP) are characterized by a transmembrane pore-type architecture that facilitates transport across biomembranes of water and a variety of low molecular weight solutes. They are found in all parts of life, with remarkable protein diversity. Very little is known about MIP from fungi. And yet, it can legitimately be stated that MIP are pivotal molecular components in the privileged relationships fungi enjoy with plants or soil fauna in various environments. To date, MIP have never been studied in a mycoparasitism situation. In this study, the diversity, expression and functional prediction of MIP from the genus Trichoderma were investigated. Trichoderma spp. genomes have at least seven aquaporin genes. Based on a phylogenetic analysis of the translated sequences, members were assigned to the AQP, AQGP and XIP subfamilies. In in vitro and in planta assays with T. harzianum strain Ths97, expression analyses showed that four genes were constitutively expressed. In a mycoparasitic context with Fusarium solani, the causative agent of fusarium dieback on olive tree roots, these genes were up-regulated. This response is of particular interest in analyzing the MIP promoter cis-regulatory motifs, most of which are involved in various carbon and nitrogen metabolisms. Structural analyses provide new insights into the possible role of structural checkpoints by which these members transport water, H2O2, glycerol and, more generally, linear polyols across the membranes. Taken together, these results provide the first evidence that MIP may play a key role in Trichoderma mycoparasitism lifestyle.