A recent groundbreaking study conducted by scientists at the University of California, Berkeley, and the University of California, Davis, has showed a novel approach to producing vital components of human breast milk through genetically engineered plants. Published in the journal Nature Food, the research highlights the potential for plants to manufacture a variety of human milk oligosaccharides (HMOs), essential prebiotic sugars known for their role in disease prevention and promoting healthy gut bacteria.
Human breast milk naturally contains a unique mix of approximately 200 HMOs. These sugars are challenging, if not impossible, to synthesize using traditional methods. The new research offers a promising alternative by leveraging the natural sugar-making capabilities of plants.
“Plants are these phenomenal organisms that take sunlight and carbon dioxide from our atmosphere and use them to make sugars. And they don’t just make one sugar — they make a whole diversity of simple and complex sugars,” explained Patrick Shih, senior author of the study and an assistant professor of plant and microbial biology at UC Berkeley’s Innovative Genomics Institute. “We thought, since plants already have this underlying sugar metabolism, why don’t we try rerouting it to make human milk oligosaccharides?”
The research team, led by first author Collin Barnum, successfully reprogrammed the sugar-making machinery of the Nicotiana benthamiana plant, a relative of tobacco. They introduced genes responsible for enzymes that create the specific linkages found in HMOs. This genetic modification enabled the plants to produce 11 known HMOs, along with various other complex sugars with similar structures.
“We made all three major groups of human milk oligosaccharides,” Shih stated. “To my knowledge, no one has ever demonstrated that you could make all three of these groups simultaneously in a single organism.”
Barnum further optimized the process to produce a specific HMO, LNFP1, which is particularly beneficial but difficult to manufacture at scale using conventional microbial fermentation methods. “We thought that if we could start making these larger, more complex human milk oligosaccharides, we could solve a problem that the industry currently can’t solve,” Barnum said.
At present, only a few HMOs can be commercially produced using engineered E. coli bacteria. The process is expensive and involves separating the beneficial molecules from toxic byproducts, resulting in a limited inclusion of these sugars in baby formulas.
As part of their study, Shih and Barnum collaborated with Minliang Yang from North Carolina State University to assess the cost of producing HMOs from plants on an industrial scale. Their findings suggest that plant-based production could be more cost-effective than microbial methods.
“Imagine being able to make all the human milk oligosaccharides in a single plant. Then you could just grind up that plant, extract all the oligosaccharides simultaneously, and add that directly into infant formula,” Shih envisioned. “There would be a lot of challenges in implementation and commercialization, but this is the big goal that we’re trying to move toward.”
This innovative research paves the way for potentially healthier and more affordable baby formulas, as well as more nutritious non-dairy plant milks for adults, by harnessing the power of genetically engineered plants to produce essential human milk sugars.
(Source: University of California)
