Fuel ethanol bioproduction from inulin rich feedstock

Abstract

Due to its important environmental benefits, bioethanol promise to be a good biofuel substitute for gasoline. To make it competitive with other fuels, the production costs should be reduced by using alternative raw materials. Inulin rich feedstock, like dahlia (Dahlia hortensis) and Jerusalem artichoke (Helianthus tuberosus) tubers or chicory (Cichorus intybus) roots would be a cheap and convenient source for fermentable sugars for bioethanol production. These are suitable crops for European countries and in low-requirements environmental conditions. Two processes were studied for conversion of inulin rich feedstock to fermentable sugars:”acid-based” and ”enzymebased” hydrolysis. The fermentable sugars (mainly fructose and low amounts of glucose) are then fermented using different alcohol-tolerant Saccharomyces cerevisiae yeast strains. Direct fermentation of inulin to ethanol was also performed, as some Kluyveromyces spp. yeast strains were found to have the ability to ferment inulin. This paper highlights the on-going developments in fuel ethanol bioproduction from inulin rich feedstock, with focus on inulin hydrolysis which is the major problem of the overall process.