While the worldwide demand for rubber continues to rise, the production of natural rubber is coming under pressure. For Europe, this is reason enough to go in search of alternatives. The EU-PEARLS project studies the possibilities to set up sustainable rubber production using the Russian dandelion and the desert plant guayule as a basis.
Car tyres, shoe soles, O-rings, catheters and surgical gloves. The raw material rubber is used in the processing of thousands of products. As a result of the growth of the world population and car ownership, the demand for rubber is on the rise. The expectation is that the plantations in Southeast Asia growing Hevea brasiliensis,the traditional rubber tree, will barely be able to continue to meet the demand for rubber.
Supply of rubber
An additional threat to the supply of rubber is a persistent fungus that is capable of wiping out entire plantations. The absence of a genetic variant of the rubber tree, the slow growth and the long period required to get production running means that classical or molecular improvement is not a very viable option.
The EU-PEARLS project (EU-based Production and Exploitation of Alternative Rubber and Latex Sources) was set up to reduce dependence on the rubber tree. The project studies the possibilities of using the Russian dandelion and the desert plant guayule on a commercial scale to establish sustainable European rubber production.
Dandelion and guayule
In the rubber extraction process, the sap of the rubber tree, also known as latex, is drawn from the tree. This latex consists of over thirty per cent rubber. After improvement, the alternative plants can produce a rubber content of around ten per cent. For this reason, the researchers feel these plants are very promising; both plants have been known for their production of rubber for decades. “During the Second World War, tyres were made from the Russian dandelion,” according to Hans Mooibroek of Wageningen UR Food & Biobased Research. “We also expect to be able to increase the rubber percentage through the selection and improvement of the plants and by determining the optimal cultivation conditions. To do this, we are also looking for other dandelion varieties in the mountains of Kazakhstan. We have already found several species that we will use in cross-fertilisation.”
Desert plant
Since the start of the project in 2008, researchers have been mapping out the genes which are involved in the rubber synthesis process. This information is used in the selection and improvement of the plants. They are also conducting field tests to determine the optimum climate and soil conditions. The Russian dandelion is particularly suitable for the countries of Northern Europe, whereas the desert plant guayule requires a hot and dry climate, such as that found in the areas around the Mediterranean. This summer, a first field test using guayule was conducted in the French city of Montpellier, with successful results.
From plant to tyre
Within the EU-PEARLS project, methods to improve the extraction of rubber are also being examined. Hans Mooibroek explains: “In the Russian dandelion plant, the rubber is in the roots. As soon as you break the roots, the sap starts to run out. In the desert plant guayule, the rubber is located in special cells in the leaves and the stalk. A painstaking extraction process using a hammermill is necessary in order to extract the rubber from these cells. An improvement in this process is necessary for the commercialisation of this product. However, this is worth the investment since the rubber from guayule does not contain the proteins that cause rubber allergies in some people. This makes the guayule rubber suitable for high-quality applications.”
The biosynthesis of rubber
EU-PEARLS is also placing attention on the technical quality of the rubber, the economic viability of European rubber production, and the commercialisation of the residual products. In these efforts, the researchers are working with companies that will be producing tyres and surgical gloves using the extracted rubber. Food & Biobased Research, fulfilling the role of project coordinator for EU-PEARLS, is working on methods to map out the biosynthesis of rubber and the genes involved in this process. To do this, yeasts are used as a model system.
European rubber
Wageningen researchers are also working on the extraction of latex and rubber from the Russian dandelion, and on the analysis of quality aspects such as molecular weight and purity. “Our goal is a sustainable and profitable production chain for European rubber,” Hans Mooibroek says. The first publications on this project are expected in the autumn of 2010.
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