The multidisciplinary EU-PEARLS project aims at the development of two alternative natural rubber sources for Europe; rubber production from guayule and Russian dandelion.

This concept is new for Europe in the sense that there are no previous EU projects devoted to local natural rubber production to build upon. The project fits well in other EU initiatives, such as “Plants for the future”.

Until now, the plant species guayule, an indigenous shrub of Mexico and the southern states of the USA, has attracted most attention. The rubber from guayule has similar polymeric properties as rubber harvested from the rubber tree. Moreover, it meets the new ASTM standard for rubber that is hypoallergenic (low in protein, and different proteins from Hevea). Over the last decades, research and development on guayule has principally occurred in the USA.

Russian dandelion has shown its potential already during World War II when army vehicles were equipped with tyres made from Russian dandelion rubber, but much RTD efforts are needed to achieve the same technology level currently enjoyed by guayule.


Almost all natural rubber is harvested from the rubber tree Hevea brasiliensis, which is currently able to supply the market. However, the rubber tree suffers from a number of threats and drawbacks: clear drivers for the development of alternative sources of natural rubber.

  • The rubber tree plantations have very limited genetic variability, which results in threats by pests and disease, most notably South American Leaf Blight (SALB). Rubber production is geographically limited to tropical zones mainly in South-Asian countries (80% of which in Malaysia, Indonesia, and Thailand). For now, SALB has been kept out of Asia by a strict quarantine. However, SALB and other plant diseases are threats to a strategically important material: Europe should develop alternative sources "just in case". Therefore, the EU-PEARLS consortium has responded to the public consultation on the EC Raw Materials Initiative, which is currently focused on rare minerals and metals.
  • Proteins in Hevea latex cause life-threatening, IgE-mediated, latex allergy; protein removal from Hevea latex is cumbersome and expensive. This results in a market for hypoallergenic latex from guayule and Russian dandelion, as currently developed by the US company Yulex for guayule.
  • Rapid increases in rubber demand, especially in rapidly growing large economies such as China and India, have caused volatile prices. Moreover, existing rubber tree plantations are being replaced by palm oil plantations. In the long term, production from the rubber tree may be not be sufficient to supply the market. Development of rubber crops for Europe also strengthens the goal of a sustainable industry, because both crops contain by-products that can also be used for the production of energy or chemicals.
  • Climate change threatens agriculture worldwide. However, Southeast Asia is one region predicted to be especially vulnerable, as detailed in a report by the EEPSEA (Economy and Environment Program for Southeast Asia). The present record prices for natural rubber (April 2010) are due to exceptional drought in Southern China and Northern Thailand, Laos, and Vietnam, while rains disrupted tapping in Indonesia. These events may or may not be early manifestations of climate change, affecting natural rubber production, but illustrate possible future events.
  • Rubber tapping depends on cheap manual labor, leading to increasing production costs and difficulties to hire workers as the producing countries develop their economies. In contrast, cultivation and processing of guayule and Russian dandelion will be fully automated, which is necessary because of high labor costs in Europe. In the case of Russian dandelion, processes similar to the sugar beet industry may be envisaged.



Key strategic objectives of EU-PEARLS

  • Development of Russian dandelion as a crop for rubber, inulin and bio-energy production in Europe
  • Development of guayule for latex, dry rubber, resins (terpenoids, fatty acids), lignin and bio-energy production in Europe
  • Development of processing methods and technology
  • Establishment of a processing industry
  • Incorporation in existing and new production chains

In short: EU-PEARLS aims at setting up production and application chains for natural latex and rubber in Europe.



Rubber pathway analysis & improvement

To increase the production of rubber and the agricultural productivity of Russian dandelion and guayule we will investigate the biochemical pathways involved in rubber biosynthesis. Understanding the transcriptional regulation of and potential bottlenecks in the underlying pathways would allow us to improve the amount and quality of the rubber. To accomplish this, genes encoding proteins/enzymes that enable an increased flux of acetyl-CoA to isoprene units (IPP) and in the final steps of rubber biosynthesis will be identified and analysed.

Guayule germplasm and agronomy

As guayule is already partially domesticated our objective is to define the potential - in Southern Europe - for cultivation of existing lines of guayule available from the USDA, using agronomic practises already established in the USA. Biomass and latex samples from different tissues, developmental stages and different guayule lines will be produced by PRI and CIRAD. A NIRS (near-infrared spectroscopy) method to determine latex and rubber content will be developed to allow measurements under field conditions.

Germplasm, breeding and agronomy of Taraxacum koksaghyz (Russian dandelion)

Russian dandelion has not been subjected to systematic breeding efforts, and most lines developed between 1930 and 1950 in various programmes have been lost. Therefore, germplasm of T. koksaghyz will be collected in Central Asia, its centre of diversity, and subsequently characterized for rubber properties and genetic diversity. Genetic maps for molecular rubber breeding in T. koksaghyz will be developed, and genes limiting rubber production and their regulatory elements will be identified. Using this information, improved T. koksaghyz germplasms will be generated by combining natural genetic variation, induced mutations and introgressed genes. Agricultural performance will be investigated in the greenhouse and small field plots. In the third year two large field trials in Germany and Spain will be conducted to produce dandelion rubber which will be used for further processing and application testing.

Extraction of guayule rubber, application testing and development of products

Latex produced from EU-grown guayule will be tested, to be able to select suitable sites for commercial guayule farms, as well as best growing and extraction practices for Europe. Performance properties required in commercially-acceptable dipped and foamed latex products will guide this selection. Bulk (or solid) rubber applications will also be evaluated from practical and economic perspectives. The data, together with those from the closely related WP3 will allow a complete economic analysis of the opportunity for profitable guayule production in the EU. WP5 will have strong links with WP6 which will build on the guayule experience.

Extraction of rubber from Russian dandelion, application testing and development of products

This workpackage is concerned with isolation of rubber from the Russian dandelion, via determination its basic polymer properties into finally making prototype products derived from it. It will give insight in the relation between the extraction methods and the final rubber material properties that can be obtained. WP6 will have strong cross-links with WP5 (extraction and application of guayule rubber) and WP4 (germplasm breeding and agronomy of dandelion).

Desk-studies on biorefining co-products and on socioeconomic issues

A desk-study on biorefining co-products from guayule and Russian dandelion will track and summarize new developments in biorefining and co-product valorization relevant to the EU-PEARLS project, while the desk-study on socioeconomic issues will help the team to judge the effect of external influences affecting the economics of producing natural rubber from guayule and Russian dandelion.