Our modern
human diet is remarkably versatile. Modern farming practices and technological
innovations allowed an unprecedented variety of dietary choices. Our hunter-gatherer
ancestors, though, didn't have this luxury. The harsh climate during cold
seasons forced them to hunt for prey to satisfy their caloric needs when 
plants were too scarce. The hunting pressure was so high that it drove many
species to extinction, including mammoths.

In their
stride to prove that our civilization is now capable of eating ancient prey
without engaging in the hunt, our Belgium-based food ingredients start-up Paleo
resuscitated a heme-protein from these ancient pachyderms. Food scientists reconstituted
the myoglobin sequence from the steppe mammoth, Mammuthus trogontherii,
in collaboration with the Center for Palaeogenetics in Stockholm, Sweden. The
corresponding genetic material, isolated from the molar of a million-year old mammoth
found nearby the Adycha river in Siberia, is the oldest DNA ever sequenced to
date (van der Valk et al. Nature 2021 - DOI:10.1038/s41586-021-03224-9).

So how did
they obtain animal protein without the animal?

With a
little help from yeasts.

With the
right instructions, yeast cells can produce large amounts of a desired protein.
This technology, called precision fermentation, combines careful microbial
genetic engineering with the age-old fermentation process. It revolutionized
medicine in the 1980s by providing diabetics with pure human insulin, when they
were previously treated with pig pancreas extract. And it can provide a way to revolutionize food protein.

Now you can even eat an extinct species

Myoglobin
is found in animal muscles. The heme group in myoglobin contains iron, and is
responsible for binding oxygen. Therefore, the presence of myoglobin
constitutes a fundamental component of the desirable meat and fish color, aroma
and nutritional content.

We unlocked the potential of this scalable technology platform to offer a much
wider choice of food ingredients, starting with animal
myoglobin of non-animal origin. Yeast cells get instructions to synthesize
myoglobin and release it in the fermentation medium. It is then purified and
concentrated. The final product is a bioidentical myoglobin devoid of
leftover microbial cells and DNA, produced with only a small fraction of the
land and water usage required for conventional meat production. It is even GMO-free, if you worry about that sort of thing.

Credit: http://cloudinary.com

Paleo
produces myoglobin from some of the most commonly consumed species, including
beef, chicken, pork, sheep and tuna, to be used as ingredients in plant-based
meat and fish alternatives in order to enhance their sensorial and nutritional
value. But we went a step further, and reasoned that myoglobin from animals
with an extreme oxygen demand – for example due to gigantism  – show distinctive adaptations that may be
beneficial for food manufacturers, too.

For
example, myoglobin from elephants (and mammoths) carries a phenylalanine at
position 30 of the amino acid chain. Other species have a leucine at this
position. The side chain of phenylalanine protects the iron atom from
autooxidation by stopping water from entering the heme binding pocket. This
adaptation, in turn, limits the undesirable shift in myoglobin color from
bright red to brown. 

What makes
the steppe mammoth myoglobin unique is a histidine at amino acid position 92,
instead of the glutamine commonly found in other species. This positively
charged residue increases the net surface charge of the protein. An elevated
surface charge is an adaptation observed in diving mammals, where it correlates
with increased muscle myoglobin concentration.

By
increasing electrostatic repulsion between the protein molecules, this prevents
detrimental myoglobin self-aggregation. Since protein aggregation is a common
issue when expressing exogenous proteins in microbes, the mammoth myoglobin
turned out to be an ideal candidate for Paleo.

This is
only a first example of how nature-inspired innovation can help us shift to
more diverse food production methods. Eating a protein
from an extinct species proves that we can still have the meat or fish
experience that is part of human culture for millennia, without animals having
to pay for it.