In the 19th century, Brazil dominated the global market in natural rubber - but the country now accounts for less than 1 per cent of world production, because of a fungus called Microcyclus ulei, which attacks the leaves of rubber trees. It has caused a massive fall in latex production. Scientists are breeding varieties of H. brasiliensis that are resistant to the M. ulei fungus.
Because of the possibility of spread of the fungus to Indonesia, Malaysia and Thailand which account for around 72%, alternative sources of polyisoprene, the chemical precursor rubber, are being sought. Oil is a possible source of synthetic rubber but car tires still require latex based rubber for the right properties.
ScienceDaily (Sep. 11, 2009) — Most natural rubber comes from rubber trees in Southeast Asia, but this source is now under threat from a fungus. Researchers have optimized the Russian dandelion to make it suitable for large-scale rubber production.
Rubber produced in this way can, however, cause allergic reactions, which is clearly an issue with clinical products. A fungus is also creating concern for rubber cultivators. In South America the infection is now so widespread that large-scale cultivation has become virtually impossible. The disease now also appears to have taken root in Southeast Asia’s rubber belt. Fungicides still provide at least temporary protection. But if the fungus disease was to reach epidemic proportions, chemical crop protection would be rendered useless – experts fear that the natural latex industry could collapse if that were to happen.
the Russian dandelion. Germans, Russians and Americans produced rubber from this plant during the Second World War. Once it is cut, latex seeps out, albeit difficult to use as it polymerizes immediately. Scientists from the Fraunhofer Institute for Molecular Biology and Applied Ecology IME in Aachen have now come a step nearer to large-scale rubber production from dandelions.
“We have identified the enzyme responsible for the rapid polymerization and have switched it off,” says Prof. Dr. Dirk Prüfer, Head of Department at the IME. “If the plant is cut, the latex flows out instead of being polymerized. We obtain four to five times the amount we would normally. If the plants were to be cultivated on a large scale, every hectare would produce 500 to 1000 kilograms of latex per growing season.”
Dandelion Rubber? Researchers Make Russian Dandelion Suitable For Large-scale Rubber Production