Biological feedstock development as part of the domestication and commercialization of Taraxacum kok-saghyz, a potential domestic source of natural rubber and inulin: progress and outlook

The Ohio BioProducts Innovation Center (OBIC) and its private- and public-sector collaborators employ a market-pull approach to accelerate the commercialization of renewable specialty chemicals, polymers/plastics and advanced materials. Taraxacum kok-saghyz (TKS) roots contain high levels of inulin and high quality natural rubber but TKS is currently undomesticated. Since2006, a private-public, multi-institution, multi-disciplinary team, formally recognized as the Program of Excellence in Natural Rubber Alternatives (penra.org), has worked to position TKS as a sustainable, domestic source of natural rubber and inulin. The team has addressed each step in the emerging TKS value chain by developing a TKS breeding program, improving existing TKS root processing methods, and securing modern evidence of the quality of TKS-derived natural rubber. Roots of unselected, wild-collected TKS genotypes contain, on average, 1.4 and 56.4 percent rubber and inulin, respectively, both below thresholds for commercialization. Therefore, classic and molecular approaches have been employed in TKS biological feedstock development. In two years and one plant generation, the average root rubber level has increased to 7.9%. Also, root rubber levels exceed 10% (commercialization threshold) in 29% of the plant population and 20% in 0.3% of the individuals tested. The breeding program contains 4,000 plants and 2551 genotypes which have been employed in creating 2.84 mil (1.8 kg) F1 TKS seed of varying pedigree, a 473-fold increase in the overall number of TKS seed available at project initiation in 2006. Field and greenhouse stock contain an additional 21,000 unique, untested TKS specimens, approximately 525 of which may contain rubber levels exceeding 15%. Natural rubber extracted from U.S.-grown TKS plants using our water-milling protocol and subjected to ASTM D3184 testing possesses properties similar to Hevea-based NR, the industry standard.