Monday, May 5, 2008
8-09

Pretreatment of reed by wet oxidation and applicability of the pretreated material in ethanol production and cellulase enzyme fermentation

Nóra Szijártó1, Zsófia Kádár1, Enikő Varga1, Anne Belinda Thomsen2, Maria Costa-Ferreira3, and Kati Réczey1. (1) Department of Applied Biotechnology and Food Science, Budapest University of Technology and Economics, Szt. Gellért tér 4, Budapest, 1111, Hungary, (2) Biosystems Department, Risoe National Laboratory, P.O. Box 49, Roskilde, 4000, Denmark, (3) Department of Biotechnology, National Institute of Engineering, Technology and Innovation, Estrada do Paço do Lumiar 22, Lisbon, 1649-038, Portugal

Reed (Phragmites australis) is a large perennial grass native to wetland sites at temperate and tropical latitudes. Due to its relatively high cellulose (36%) and hemicellulose (21%) content, reed is often recognized as a potential substrate of various lignocellulose based bioprocesses. However, at the moment it is among the least characterized residues considered for such purpose. The production of second generation bioethanol (often coupled with the fermentation of cellulase enzymes needed in large quantities within the same process) is predicted to become the largest bulk technology to utilize lignocellulose biomass soon. In order to remain sustainable no residue available locally with sufficiently high ethanol potential can be left unutilized and therefore the evaluation of reed for its convertibility to ethanol is a must at the geographical sites under discussion.
Among the available physico-chemical methods developed for the pretreatment of lignocellulosics, wet oxidation is a relatively novel development, which was successfully applied to reed in the present study. Wet oxidation employing various reaction temperatures (185°C - 200°C) for 12 min using 2 g/L Na2CO3 as the catalyst was evaluated via the characteristics of produced solids obtained after various treatments. Enzymatic convertibility of the cellulose content of the pretreated material by cellulases, fermentability of the hydrolyzed cellulose to ethanol by Saccharomyces cerevisiae, and applicability of pretreated material in cellulase enzyme production by Trichoderma reesei were investigated in the present study. Results will be presented and discussed at the conference as the measure of obtained conversion, ethanol yield, and cellulase activity, respectively.