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Journal of Atomic and Molecular Physics
Volume 2013 (2013), Article ID 791353, 7 pages
http://dx.doi.org/10.1155/2013/791353
Research Article

Improving Anaerobic Digestion of Wheat Straw by Plasma-Assisted Pretreatment

1Department of Chemical and Biochemical Engineering, Technical University of Denmark, 2800 Lyngby, Denmark
2Department of Geochemistry, Geological Survey of Denmark and Greenland (GEUS), Øster Voldgade, 1327 Copenhagen K, Denmark
3Department of Physics, Technical University of Denmark, 2800 Lyngby, Denmark
4Masdar Institute, P.O. Box 54224, Abu Dhabi, United Arab Emirates

Received 12 February 2013; Accepted 27 March 2013

Academic Editor: Jayr de Amorim Filho

Copyright © 2013 Stefan Heiske et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Plasma-assisted pretreatment (PAP) of lignocellulosic biomass has been shown to be an efficient method to decompose lignin and consequently facilitate microbial access to cellulose and hemicellulose. In the present study, PAP was tested for its suitability to enhance bioconversion of wheat straw to methane. In thermophilic batch experiments, methane yields of up to 366 mL/g volatile solids (VSs) were achieved, accounting for a yield increase of 45%. Common lignin-derived inhibitors like 5-hydroxymethylfurfural (5-HMF) and furfural were not detected after PAP, but toxicity test resulted in lower methane yields at higher substrate concentrations, indicating the presence of other unidentified inhibitors. However, in a continuous lab-scale biogas reactor experiment, stable codigestion of cattle manure with 20% PAP wheat straw was demonstrated, while no signs of adverse effects on the anaerobic digestion process were observed. After the introduction of the pretreated wheat straw to the reactor, volatile fatty acid concentrations remained low and stable, while gas production increased. In co-digestion, the PAP wheat straw was converted at an average yield of 343 mL CH4/gVS.