Abstract
Biomass is a valuable alternative to conventional fossil fuels for energy production through gasification. This process leads to the formation of toxic condensable compounds (tar) mainly composed by straightchain, cyclic and heterocyclic hydrocarbons. Bioremediation is an approach for the handling of these residuals. The aim of this research is to study the degradation capability of a laboratoryscale microcosm where microbial consortia are used for the treatment of tar after steam gasification of wood. Steam gasification was carried out at 700800°C using wood pellets. Samples of the residual tar were collected and diluted in toluene. Microbial communities were grown in microcosms filled with tar. Microbial analyses were performed through Denaturing Gradient Gel Electrophoresis (DGGE) and DNA band sequencing of the metagenomic DNA extracted from each microcosm. Tar residuals were characterized by Gas ChromatographyMass Spectrometry (GC/MS). The microbial consortium was dominated by bacterial species belonging to the genera Arthrobacter, Paenibacillus and Flavobacterium, and of Geotrichum for fungal community. GC/MS analyses of the microcosms showed that the presence of several hydrocarbons were reduced by almost 100% after an incubation period of 20 days. A complex bacterial and fungal consortium able to bioremediate a wood tar was selected. Its bioremediation capability was assessed reducing significantly the organic volatile solvents as furfural and alcohols.