Effect of biodegradation on thermogravimetric and chemical characteristics of hardwood and softwood by brown-rot fungus

The thermogravimetric and chemical characterization of hardwood Eucalyptus urophylla (Ep) and softwood Pinus massoniana (Mp) pretreated by brown-rot fungus Gloeophyllum trabeum were investigated. The results indicated that the brown-rot fungus pretreatment can optimize the thermal decomposition and decrease the initiation temperatures (8-11 °C lower) of both the Ep and Mp pyrolysis. The mean activation energy values of the bio-treated samples were 29.7 kJ/mol (for Ep) and 42.3 kJ/mol (for Mp) lower than that of the un-treated samples at the conversion rate from 0.1 to 0.7 based on Flynn-Wall-Ozawa (FWO) method. After the bio-pretreatment, the required temperatures were lower (4-7 °C) for the pyrolysis rates of hemicellulose and cellulose in Mp reaching maximum and termination. However, the situation was just the opposite for Ep. The variations in chemical properties of hydrogen bonding, as well as the relative changes in lignin/carbohydrate composition of both wood species were also examined.