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Gene Editing

Engineered plants make human milk compounds

Infant formula doesn’t fully replicate human milk. Scientists are turning to genetic engineering to get closer

by Max Barnhart
June 17, 2024


Chemical structure of a oligosaccharide molecule found in human milk.
An example of a complex, fucosylated human milk oligosaccharide that can be produced by genetically engineered plants.

Over 200 different carbohydrates in human milk help form a composition of nutrients suited for the express purpose of feeding a growing child. Yet roughly 75% of infants around the world don’t get their nutrition solely from human milk. Many get part or all of their nutrition from infant formula, which may contain only one or two of those important carbohydrates, if any. Now researchers publishing in Nature Food describe how plants can be modified to produce a diverse array of human milk oligosaccharides (HMOs) (2024, DOI: 10.1038/s43016-024-00996-x).

Other methods for producing HMOs, including microbial fermentation, have existed for years. But according to Collin Barnum, a synthetic biologist formerly at the University of California, Davis, and lead author of the paper, microbes are “only able to produce a small subset of HMOs [that is limited to] these kind of smaller, less complex HMOs.” That’s where plant production can help. Plants possess highly advanced biological pathways for producing carbohydrates via photosynthesis, which the researchers adapted to synthesize 11 different HMOs, including complex fucosylated HMOs that are difficult to make by other means.

That impresses Steven Townsend, an oligosaccharide chemist at Vanderbilt University who wasn’t involved in the research. He says better production methods for those HMOs was needed and current manufacturing can’t “match the scale nor structural diversity of plant engineering or microbial fermentation.”

But much development is required before plant-produced HMOs could become commercially viable. The steps include “optimization of yields, a validated extraction platform, and [regulatory approval] for growing genetically modified plants,” Barnum says. Townsend adds that more research is needed to understand how supplementation with these compounds will improve infant nutrition. “Whether or not these additives are as effective as the personalized product Mom provides is to be determined,” he says.



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