By Ryan Flinn
Baker's yeast, commonly used to make beer and bread, can be engineered to produce a key ingredient for malaria drugs, according to researchers who say the method offers a new way to boost needed supplies.
Antimalarial medications save millions of lives, yet the supply of the sweet wormwood tree, the source of the most effective treatment, artemisinin, can fluctuate year to year, creating shortages. The study published Wednesday by the journal Nature, and funded by the Seattle-based Bill & Melinda Gates Foundation, describes how the new process boosts production of artemisinic acid by almost 16 times the amount of previous approaches.
"Prior to this, nobody had been able to get a high level production of artemisinin," Chris Paddon, a study author, said in an interview. "This is a big genetic engineering breakthrough."
Paddon, principal scientist for Amyris Inc., an Emeryville, Calif.-based renewable chemicals and fuels company, said the intellectual property rights for the process described in the paper have been donated for nonprofit use in order to boost production.
The process resulted in 25 grams of commercially usable artemisinic acid concentration per liter, compared with previous methods that led to 1.6 grams per liter. Artemisinic acid is then converted into the drug artemisinin, which is combined with other antimalarial treatments to ensure the parasites that cause the disease are cleared.
Sanofi, the Paris-based maker of Lantus insulin, will start using this method beginning tomorrow to produce semi-synthetic artemisinin, Paddon said.
Malaria kills a child in Africa every minute, according to the Geneva-based World Health Organization. The disease is spread through mosquitoes infected with the Plasmodium parasite, which multiply in the human liver, attacking red blood cells. It strikes about 216 million people each year and kills about 655,000.
"The key issue for the manufacture of these artemisinin combination therapies is that it's an agricultural product and so the prices vary hugely year to year, as does the supply," Roly Gosling, lead of the University of California, San Francisco's Global Health Group's Malaria Elimination Initiative, said in an interview. "This of course has a huge impact on public health programs."