Episode Summary

Pat Brown, founder Impossible Foods.
Pat Brown founded Impossible Foods with a mission to replace animals as a food production technology. Here, he discusses the ways microbial engineering helps produce the plant hemoglobin that provides the Impossible Burger’s meaty qualities.

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Julie’s Biggest Takeaways

Impossible Foods was founded with a mission to completely replace meat, fish, and dairy foods out of plants. Eliminating the agricultural impact that comes with raising livestock will use less resources and produce less pollutants. Making Impossible Burgers uses 1/10 the water, less than 1/25 the land, less than 1/10 the fertilizer input, which will benefit the environment and consumers’ pocketbooks. Lower resource use means lower cost at scale.

We have a lot of livestock on this planet. The total biomass of cows on earth today exceeds the total biomass of every remaining land vertebrate on this earth by a factor of 10. Domesticated pigs exceed by a factor of 2. Chickens exceed every other wild bird by a factor of 3. The space these animals require decreases the local biodiversity.

The Impossible Burger requires 2 microbes to mimic the taste of meat: the rhizobia that colonize the root nodules of soybeans and influence the plant to produce leghemoglobin to regulate the oxygen concentration, and the yeast that are used to recombinantly produce that leghemoglobin.

Eliminating the land required to raise agriculture will not only lead to less resource use and pollution generation from the animals, but will also have a positive effect as biodiversity of these lands increases and fixes more carbon dioxide into its biomass.

The food and agricultural industries offer some of the greatest opportunities for scientific innovation. Pat suggests a long-term goal of using an easily renewable protein such as the photosynthesis protein RuBisCO (amino acid balanced for human nutritional needs) as a source of plentiful, sustainably sourced protein.

Featured Quotes

“The whole reason the company exists and the reason we have so many amazingly great scientists working here is that we are working on the most important and urgent problem in the world right now. Arguably, the most important and urgent problems our species has ever faced are the catastrophic meltdown in biodiversity and the relentless progression of climate change, both of which the use of animals in the food system is a major player.”

“You’d have to be trying not to make a product that has a better nutritional profile and a vastly lower environmental footprint than the incumbent animal-based products. The hard part, and it is hard, is figuring out how to make it more delicious as judged by meat lovers. That’s what makes it an interesting scientific problem, and a hard one.”

“The most important scientific question in the world right now is why does meat taste delicious. If we can answer that question successfully, we can eliminate and reverse the environmental threat.”

“Every living plant or animal cell contains heme. From a food standpoint, what matters is that heme catalyzes very specific types of chemical reactions that transform abundant, simple nutrients into this explosion of hundreds of diverse volatile odorant molecules. When you experience them together, they add up unmistakably to the smell and taste of meat.”

“The thing about microbiology is: it’s a vast fraction of all life on earth that you’re studying. A vast fraction of all the biochemical processes that are possible in nature. There is no wall around microbiology; it’s not a silo. It’s seamlessly connected to almost everything in biology.”

Links for This Episode

History of Micobiology Tidbit


Should I discuss the rhizosphere or root nodules? Development of Pichia as a biotech workhorse? These all lead to interesting histories, but I started thinking about cyanobacteria and Pat’s far out suggestion to harvest cyanobacteria to use their photosynthesis machinery as a protein source for people. Side bar: was I the only one picturing Mr. Trash Wheel in my head as a cyanobacteria collection mechanism? Mr. Trash Wheel is a contraption that sits in Baltimore Harbor and is constantly filtering water to remove bits of garbage. I don’t know when this contraption had eyes added to make it look like a giant mouth is sucking up the trash, but there you have it. I was imagining Mr. Trash Wheel with a filter designed to collect cyanobacteria in the middle of the ocean - or maybe a family of Trash Wheels - as Pat was discussing the use of this unconventional protein source.

Mr. Trash Wheel. By: Matthew Bellemare

What a cool idea for cyanobacteria! Here’s another cool idea: cyanobacterial products used for sunscreen. Sounds crazy, but cyanobacteria are excellent at protecting themselves from the sun. Cyanobacteria were the first organisms to develop photosynthesis billions of years ago. As they began to harvest energy from light, the requirement of the bacteria to be in the presence of light began to become risky, since in addition to getting energy from the sun, they also received UV radiation. Some 2-ish billion years ago, a progenitor of one present day cyanobacteria began to produce a secondary metabolite called scytonemin. Scytonemin is built from several aromatic amino acids to form an indole-alkaloid that can absorb wavelengths broadly across UVC/UVB/UVA spectra. It’s a great microbial sunscreen, and its use in people was suggested in a 2017 paper.

The microbial sunscreen scytonemin was discovered by Carl von Nägeli, a Swiss doctor and naturalist who was most active in the mid-1800s. Nägeli made a number of discoveries, published in German of course, about algae and about plants. He may not have known the structure of scytonemin, but he observed its induced expression, and wrote about this as well as plant cell wall structure and a whole host of other natural phenomena. He coined several important botany terms, including xylem and phloem, which are still used in plant physiology. However, Nägeli is most remembered not for the discovery of scytonemin or other scientific contributions, but as the scientist who discouraged Gregor Mendel, yes that Gregor Mendel who looked at inheritance in pea plants.

As scientists did in those days, Mendel and Nägeli corresponded by letter. Mendel wrote to Nägeli about his now-classic experiments with garden peas, and this began an 8 year correspondence between the 2. Mendel undoubtedly wanted to get the scientific opinions of Nägeli, one of the most prominent botanists at the time. During his lifetime, Mendel published only two scientific papers, but the letters contained a much broader description of Mendel’s experiments and their results. Nägeli scribbled in the margins of some of these, writing “only empirical and not rational,” so it seems that Nägeli was truly unconvinced by Mendel’s work.

The kicker, which comes from Simon Mawer’s 2006 book Gregor Mendel: planting the seeds of genetics is that Nägeli ended up incorporating some of these ideas about inheritance into his own work without properly citing Mendel. According to the book, in one of Nägeli’s writings that was published the year of Mendel’s death, 1884, Nägeli proposed “the concept of the ‘idioplasm’ as the hypothetical transmitter of inherited characters,” without any credit to or mention of Mendel. Mawer writes: "We can forgive von Nägeli for being obtuse and supercilious. We can forgive him for being ignorant, a scientist of his time who did not really have the equipment to understand the significance of what Mendel had done despite the fact that he (von Nägeli) speculated extensively about inheritance. But omitting an account of Mendel's work from his book is, perhaps, unforgivable."

History focuses so much on the few who have contributed and doesn’t long remember those who have been wrong. Here is a story of an accomplished scientist who contributed quite a bit - scytonemin, plant physiology, and other discoveries I didn’t mention - yet one of his lasting impressions on the world is his failure to recognize important data. If this story has any lesson, it’s to study the data carefully before coming to conclusions.

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