Biohydrogen production by dark fermentation of Arundo donax for feeding fuel cells

Hydrogen may be considered as an alternative source of energy since it can be produced from several thermochemical and biological processes. The hydrogen obtained can be feed to fuel cells, which are the most promising devices to produce electric energy with high efficiency and very low environmental impact. The present work studies the biological H2 production by dark fermentation of Arundo donax (AD) inoculated with sewage sludge in mesophilic condition (38°C). The substrates used are AD without pretreatment (AD),and AD treated from steam explosion (AD exp) both supplemented with a nutrient medium. A synthetic medium was used as reference model. Fermentation process produce products. The liquid phase contains mainly acetic acid, butyric acid, propionic acid and ethanol that. The biogas phase contains mainly of hydrogen and carbon dioxide. Liquid and gaseous phases are analyzed by GC technique. The fermentation process is monitored reducing sugars and microbial biomass by spectophotometric analysis. Best results are obtained with AD sample as substrate that gives yield to hydrogen up to 1.34 mol H2/mol glucose fed. Biogas produced has H2 concentration up to 74% by volume being CH4 present in traces amount. It can be potentially feed directly to a PEMFC (Proton Exchange Membrane Fuel Cell), since it does not contain CO.