Submitted to: Helia
Publication Type: Peer reviewed journal
Publication Acceptance Date: 5/15/2007
Publication Date: 7/1/2007
Citation: Seiler, G.J. 2007. The potential of wild sunflower species for industrial uses. Helia. 30(46):175-198. Interpretive Summary: The desire for alternative sources of fuels, chemicals, feeds, and other materials has received increased attention in the past decades. Many researchers believe that in the future more agricultural feedstocks will be used for their special properties, since they are renewable resources, have better degradability and are more acceptable to consumers than synthetic products. Environmental issues and depletion of natural resources favor their utilization for industrial purposes. Wild sunflower species have the potential to contribute to these renewable resources. During the past three decades, the narrow genetic base of cultivated sunflower has been broadened by the infusion of genes from wild relatives, which have provided a continuous source of agronomic traits for crop improvement. Jerusalem artichoke is one of the most-mentioned candidates for use as a raw material for industrial production of biological fructose and inulin. The greatest potential of the wild sunflower species for industrial use is as a feedstock for bioethanol production. Crops such as Jerusalem artichoke produce reasonable amounts of easily fermentable carbohydrates, such as fructans, that make it a potential energy crop and an alternate source for producing petrochemicals. Jerusalem artichoke is unique in that both stalks and tubers can be used for bioethanol production. Unfortunately, maximum yield for both aboveground and tuber production can not be simultaneously obtained. However, the advantage of Jerusalem artichoke is that it is a perennial crop with biomass yields in the following years obtained by re-growth of shoots, thus avoiding tuber replanting. The wild species hold promise as sources of phytochemicals and for future improvement of cultivated sunflower as a crop for industrial uses. Further research through selection and breeding will be needed to assess the potential use of wild species for industrial uses.
Technical Abstract: Within the past decade, the desire for alternative sources of fuels, chemicals, feeds, and other materials has received increased attention. Wild sunflower species have the potential to contribute to these renewable resources. During the past three decades, the narrow genetic base of cultivated sunflower has been broadened by the infusion of genes from wild relatives, which have provided a continuous source of agronomic traits for crop improvement. The genus Helianthus is composed of 51 species and 19 subspecies with 14 annual and 37 perennial species. Although oil concentrations of up to 37 g/kg have been reported in whole plants of one wild sunflower, H. ciliaris, the achenes are the primary storage tissue for oil. The fatty acid composition of the achene oil determines its suitability for either food or industrial uses. Considerable variability has been reported in fatty acid composition of oil in achenes of the wild species. Other natural products may also be of economic value from the wild sunflower species. A natural rubber concentration of 19 g/kg has been reported in the whole plant of wild perennial H. radula with more than 92% pure rubber. Polyphenol yields of wild sunflower biomass are moderate, with H. strumosus yielding 139 g/kg. Hydrocarbon yields for wild sunflower biomass are average for most species, with H. salicifolius having the highest yield of 16 g/kg. The sugars in the stalks and tubers of Jerusalem artichoke (H. tuberosus) have been suggested as a potential source for bioethanol production. Jerusalem artichoke has been evaluated for inulin and sugar yield from stalks and stem, yielding 10.4 and 8.0 t/ha, respectively, while tubers yield 13.7 t/ha of inulin and 13.3 t/ha of fructose. Biomass production has also been investigated in Jerusalem artichoke. Dry matter forage yields of 3.0 to 9.9 t/ha and tuber yields of 2.8 to 12.8 t/ha have been reported. Further research will be needed to assess the potential use of wild species for industrial purposes through selection and breeding.