By Pat Anson, Editor
While politicians and regulators in the U.S. try to decrease access to opioid pain medications, scientists are developing new techniques to mass produce them.
The latest development is at Kyoto University in Japan, where researchers have learned how to tweak E coli bacteria so that they pump out thebaine, a morphine precursor that can be modified to make opioid pain relievers.
The genetically modified Escherichia coli – a common gut microbe -- produces 300 times more thebaine than a recently developed method involving yeast.
"Morphine has a complex molecular structure; because of this, the production of morphine and similar painkillers is expensive and time-consuming. But with our E coli, we were able to yield 2.1 miligrams of thebaine in a matter of days from roughly 20 grams of sugar,” said lead author Fumihiko Sato of Kyoto University.
"Improvements in opiate production in this E. coli system represent a major step towards the development of alternative opiate production systems."
Sato’s study is published in the journal Nature Communications.
Morphine is extracted from opium poppy sap in a process that typically takes up to a year. Morphine can then be converted to opiates such as codeine, hydrocodone or even heroin.
Scientists at Stanford University last year engineered the yeast genome so that it produces opiate alkaloids from sugar. The genetically altered yeast cells grow so rapidly they convert sugar into hydrocodone in just three to five days. That raised fears that opioids could be produced cheaply and easily, provided that one has access to the necessary yeast strain.
With E coli, Sato says that such a production risk is unlikely.
"Four strains of genetically modified E coli are necessary to turn sugar into thebaine," explains Sato. "E coli are more difficult to manage and require expertise in handling. This should serve as a deterrent to unregulated production."
In 2011, Sato and colleagues engineered E coli to synthesize reticuline, another morphine precursor. In the new system, the team added genes from other bacteria and enzyme genes from two strains of opium poppies, Coptis japonica, and Arabidopsis.
"By adding another two genes, our E coli were able to produce hydrocodone, which would certainly boost the practicality of this technique," Sato said. "With a few more improvements to the technique and clearance of pharmaceutical regulations, manufacturing morphine-like painkillers from microbes could soon be a reality."
Opioid pain medications are widely available in the United States, where the focus is often on their potential misuse. But the World Health Organization estimates that 5.5 billion people worldwide have little or no access to opioids because of their limited supply and high cost.