The bacteria-based process, known as chemoenzymatic synthesis, produces a relatively high drug yield of about 40 percent, which is important for keeping manufacturing costs down. The resulting compound is not exactly identical to the existing synthetic heparin, called Arixtra, so the drug will still need to be tested in human clinical trials before it can reach the market. But the researchers showed that their heparin is nontoxic and works well as an anticoagulant in animals.

To make a commercial product, researchers will need to scale up the chemoenzymatic method from the milligram level of the university laboratory to the kilogram level of a pharmaceutical company. "That's the big challenge," says Jian Liu, a medicinal chemistry researcher at the University of North Carolina, Chapel Hill, and one of the lead authors of the study. "But theoretically this opens the door, and hopefully industry will realize the importance of this method."

If all goes well, animal-derived heparin could be phased out within five to 10 years, says Jeremy Turnbull, a heparin expert at the University of Liverpool in the U.K., who wrote an editorial accompanying the study. "The new availability of chemoenzymatic options could be valuable for a number of disease treatments, including cancer," he says. "It should be possible to scale the process up to kilogram level or higher, but no doubt it will take further effort."