Painkillers can now be sourced from modified yeast, a new study finds. Scientists from Stanford University have found a way to coax genetically modified yeast into producing opiates, providing an alternative to produce the drugs through a simpler, shorter and more economical process.
The researchers reprogrammed the yeast to convert the sugar tyrosine into thebaine. Next, they inserted the genes needed to convert thebaine to hydrocodone, a close "relative" of morphine, according to Smithsonian.
However, at first, they were not able to yield enough opiates because the yeast was not synthesizing enough protein needed in the process.
"We then had to rewrite the instructions for how yeast should make the protein so that it more closely modeled how the plant was doing it," study author Christina Smolke said. The scientists used a total of 23 genes from bacteria, plants and rats to reconstruct the yeast cells.
"You can think of it as an assembly line process," Smolke said. "It starts with sugar which gets broken down, then begins to get built up into more complex molecules," she told The Guardian.
Using yeast to produce the painkiller substance has several advantages. First, it cuts production time - which typically takes at least a year - to just several days. Second, it removes limitations associated with poppy farming, such as drought, pest infestation and extreme weather.
All in all, using genetically modified yeast for opiate production is cheaper than conventional methods.
"With further development it can certainly have a significant difference," Smolke said. "By our estimates it will reduce the cost by about ten-fold for making these chemicals. That is an important thing because there's a large percentage of the global population that doesn't have access to these medicines."
One downside to watch out for, as pointed out by Massachusetts Institute of Technology associate professor Kenneth Oye, is if someone should develop a yeast strain that specifically converts glucose to heroin.
"If someone were to develop a strain of yeast with a pathway that went from glucose to heroin with high efficiency, then you have a problem. Such a strain might have the potential for home-brew opiates," Oye told Smithsonian.
"I believe there needs to be an open deliberative process to discuss the real concerns and how to develop strategies to mitigate these risks," Smolke said regarding Oye's comment.
The research team is now focused on making the process more efficient in order to produce 100,000 times more opiates than their initial yield in order to compete commercially with opiates extracted from traditional poppy farming methods.
"By our estimates, we would need to improve the efficiency of the process by 100,000 times to be ready for commercial production," Smolke said. "We believe this is feasible and have already begun that work."
The study was published Aug. 13 in the journal Science.
