Heparin synthesized using only enzymes

After an exploration of an enzyme’s evolution, scientists are one step closer to manufacturing the blood thinner heparin using enzymes instead of pigs. The finding could open a long-standing bottleneck in the commercial chemoenzymatic synthesis of this critical drug (Trends Biotechnol. 2026, DOI: 10.1016/j.tibtech.2026.04.028).

Drugmakers produce hundreds of metric tons of heparin each year; most of it is sourced from pig intestines, where mast cells churn out the sulfated polysaccharide. By some estimates, as many as 1 billion hogs—mostly in China—are slaughtered each year to meet demand. But this supply chain is vulnerable: a 2019 outbreak of African swine fever caused global shortages of the drug.

Academic researchers and start-ups have tried to develop chemical and enzymatic methods for making heparin, but the first step in the process has been a stumbling block. This step involves plucking acetyl groups off nitrogens in the biopolymer heparosan and installing sulfate groups in their place. The bifunctional N-deacetylase/N-sulfotransferase (NDST) enzyme that performs this task in people, pigs, and other higher eukaryotes has been tough to reproduce in a prokaryotic host like Escherichia coli, the workhorse of enzymatic syntheses. Scientists have used chemical methods to do NDST’s job, but these can break important bonds in heparosan, produce unwanted side reactions, and use chemicals that are unsuitable for large-scale production.

Juzheng Sheng, who studies enzymatic syntheses at Shandong University, says in an email that the N-deaceylation/N-sulfotransfer step has been “a central bottleneck in the non-animal chemoenzymatic synthesis of heparin for decades.”

To address this bottleneck, Sheng and Hua-Rong Shao at the Shandong Academy of Pharmaceutical Sciences led a team that used an evolutionary strategy to develop an enzyme, known as NDST-M8, that works in E. coli. “We were inspired by the concept of evolutionary intelligence: rather than fighting against nature, we let nature guide us toward a better engineering template,” Sheng says.

To develop their biocatalyst, the researchers looked at versions of NDST produced by 15 model organisms “ranging from nematodes and insects to fish and mammals, to identify candidates that could be expressed in soluble and active form in E. coli,” Sheng says. “We reasoned that evolution may have already solved the expression problem in certain species; the key was to identify the right one.”

The scientists found NDST from a mosquito-like insect that was close to what they were looking for. After computational studies and making some mutants, they landed on NDST-M8. They used this enzyme in a multienzyme cascade to make heparin analogs with varying degrees of sulfation using only E. coli.

Jian Liu, who studies biosynthetic heparin production at the University of North Carolina at Chapel Hill and was not involved in the work, says this is an important advance. “This could become a new way for large scale production of non-animal-source heparin,” he says.

Several challenges remain. Liu points out that the synthesis described in the paper uses a solution that’s too dilute to be practical; it would produce a massive amount of liquid by-product on an industrial scale. Sheng says the team need to see if the system can be scaled up successfully and to bring the cost of the process down. He and his colleagues are now collaborating with industrial partners to validate the process at the 1,000 L scale.

“For the heparin field, this work finally opens the door to a non-animal, sustainable, and molecularly precise manufacturing platform—a goal that the community has been pursuing for more than two decades,” Sheng says. But he adds that the finding is not simply about developing a better enzyme catalyst. “It represents a shift in mindset: by learning from evolution, we can overcome the long-standing assumption that eukaryotic enzymes cannot be effectively expressed in bacteria.”