Traditionally, golden rice , being a genetically modified organism, has had fierce activist resistance from a certain ideological spectrum .
You have to ask them what they think of this : genetically engineered yeast pills that settle in your gut and synthesize vitamin A from what you eat (something that could happen soon given the results obtained in mouse models).
Transgenic yeasts in mice
Most yeast species cannot survive in the mammalian gut : the heat and acidity are beyond their tolerance limits. But Saccharomyces boulardii not only grows easily in the mammalian gut, it also inhibits pathogenic gut infections in the mammalian host.
Just as golden rice is a transgenic variety that can supply vitamin A deficiencies, perhaps one day this yeast will be able to do it more effectively .
In a new step for synthetic biology, a group of researchers has opened new biosynthetic pathways in S. boulardii that allow the production of vitamin precursors (such as beta-carotene, a precursor of vitamin A) and drugs (such as violacein, a natural drug with anti-inflammatory properties) in the intestine of mice. They thus demonstrated CRISPR-mediated genome editing with high efficiency (95%) in this yeast strain .
The researchers reported that S. boulardii formed stable colonies in germ-free mice for more than 30 days, competing for space with other microbes resident in the gut.
The researchers then tested the modified S. boulardii in the mouse model and found that the yeast cells successfully synthesized beta-carotene in the gut of the mice . By comparing the total mass of additional beta-carotene recovered in the stool with the beta-carotene present in the initial dose of probiotics, the authors estimated that the germ-free mice produced 194 micrograms of beta-carotene in approximately 14 days.
This proof-of-concept study inspires further questions about the amount of beta-carotene absorbed by mice, the biological relevance of the amounts produced, and most importantly, whether the process can be replicated in humans . Be that as it may, Greenpeace is sure to be against it .