Potential of Jerusalem artichoke (Helianthus tuberosus L.) as a biorefinery crop

The utilization of Jerusalem artichoke in a biorefinery context was not investigated so far. Therefore the aim of this study was to evaluate the potential of this plant as feedstock for production of bioethanol, protein and inulin. We investigated the biomass productivity and chemical composition of 11 different clones, harvested on three occasions during the fall and early winter of 2011. The results obtained showed that cellulose production per hectare was at least double compared to corn stover, rice straw, sugarcane bagasse and wheat straw, showing high bioethanol production potential of Jerusalem artichoke. Although not high (in total <6% of dry matter), protein and lipid levels could be of importance when biomass is utilized in a biorefinery concept. Harvest occasion determined the biomass productivity and chemical composition to a higher degree than the choice of clone. The average biomass productivity was 88% higher in September than in December. Fresh tuber biomass productivity showed large variations between harvests, where the maximum average productivity in December was 3.4 times higher than in September. Inulin content in dry tubers was between 76 and 85% making the plant an excellent crop, for e.g. inulin extraction, production of high fructose syrup or fermentations. Less mature plants were shown to have degree of polymerization (DP) up to 14, which makes biomass useful as dietary fibre, while the inulin DP in tubers harvested later became as low as 6, showing lower potential with respect to plant utilization for dietary purposes. Results obtained clearly demonstrated that crop harvesting time was an important factor affecting biomass productivity and composition. (C) 2014 Elsevier B.V. All rights reserved.