Monday, April 30, 2007 - 9:00 AM

Hydrolysis of reed canary grass and barley straw for bioethanol production

Anne Kallioinen1, Liisa Viikari2, Niklas von Weymarn1, and Matti Siika-aho1. (1) VTT Technical Research Centre of Finland, P.O. Box 1000, FIN-02044 VTT, Espoo, Finland, (2) VTT Technical Research Centre of Finland, P.O. Box 1000, FIN-02044 VTT, Espoo, Finland

In recent years growing attention has been devoted to processes converting biomass into fuel ethanol. The EU Biofuel directive of 2003 accelerated this progress by setting the following goal: by the year 2010 almost 6 energy-% of all fuel consumed in the EU should be produced from biomass. Ethanol produced from biomass together with different biodiesel products are currently the most important pieces in this puzzle. 

In Finland, reed canary grass is cultivated as an energy crop for burning and it is usually harvested in the spring. Barley straw is another potential raw material in Finland since barley is widely cultivated. Because of their availability and relative high carbohydrate content, both agriculture products have potential as raw material for 2nd generation bioethanol production. The aim of the present study was to study enzymatic hydrolysis of reed canary grass and barley straw in connection to bioethanol production.

Reed canary grass harvested in the spring or autumn and barley straw were pre-treated by steam explosion and the fibre fractions were hydrolysed enzymatically in laboratory conditions. Hydrolysis was studied with commercial enzyme preparations at different dry matter consistencies, enzyme dosages and with or without fibre washing. Proper mixing was found to be vital for efficient hydrolysis. The pre-treated raw materials were not toxic for yeasts at 10% consistency and washing of pre-treated fibre material before hydrolysis was not necessary. The hydrolysis yield with reed canary grass was 95% of theoretical amount of sugars in 72 hours hydrolysis time at 10% consistency.