Engineering yeast to maximise the production of heme, a source of absorbable iron

What is it about?

Heme is produced naturally in budding yeast, which has been used by humans for thousands of years (e.g., for bread). We engineered a strain of yeast to produce 70 times more heme, using techniques of systems biology and synthetic biology. In particular, we used mathematical models of yeast metabolism to identify crucial "choke-points" that had limited heme production. We increased heme production by modifying targeted genes using CRISPR-Cas9 "scissors". Our mathematical modelling was validated experimentally. We produced a strain producing 70 times more heme than occurs in the original strain. Our validation also used biosensing techniques and ligands: We also developed a heme ligand-binding biosensor (Heme-LBB) which showed the increased intracellular heme.

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Photo by Sangharsh Lohakare on Unsplash

Photo by Sangharsh Lohakare on Unsplash

Why is it important?

Heme is important as a source of iron, which is easily absorbed during digestion. Vegans and other vegetarians have had difficulty satisfying their heme needs using only plant-based foods. Beyond vegetarians, many consumers wish to reduce their consumption of animal products to reduce their carbon footprint. Consequently, many consumers are interested in non-animal, sustainable sources of heme.

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