Will microbial meat alternatives save our forests?

Citizens

Beef like in this burger promotes deforestation and harms the climate. © dulezidar/ iStock

In order to meet the high meat consumption of the human population, forests are cleared in many places for arable land and pastures. However, replacing one-fifth of human meat consumption per capita with meat alternatives made from microbial protein could cut global deforestation by half, a study shows.

Be it cattle, pigs, sheep or goats – animal husbandry requires large areas of pastureland and lots of arable land for the cultivation of fodder, such as maize or soya. Because forests are often cut down to expand the usable areas, this increases the climate-damaging effect of livestock farming even further. Because in addition to the greenhouse gases produced by the animals, there are no trees as a carbon sink. “The production and consumption of food accounts for a third of global greenhouse gas emissions, with beef production being the largest single source,” says Florian Humpenöder from the Potsdam Institute for Climate Impact Research (PIK).

A small sacrifice with a big effect

Climate researchers have therefore been calling for a long time to reduce meat consumption – or to switch to alternatives without animal husbandry. Humpenröder and his colleagues have therefore looked at the environmental impact of a meat alternative that was developed in the 1980s and was classified as safe by the American Food Administration in 2002: microbial protein. This nutrient and protein-rich biomass is produced from fungal cultures through fermentation and is already available in supermarkets in the UK and Switzerland.

But how would it affect the entire agri-food system if the microbial protein were a regular part of our diet? The research team has now tested this in a computer simulation. The future scenarios of the researchers extend up to the year 2050 and take into account future population growth, food demand, eating habits and the dynamics of land use and agriculture. The results make it clear how strongly the waiver of individual people can have an overall effect.

Microbes only need sugar

According to the researchers, if 20 percent of beef consumption were replaced by bioengineered protein by 2050, annual deforestation and CO2 emissions would be halved. “Fewer cattle means less need for fodder and grazing land and therefore less deforestation,” says Humpenöder. But methane emissions from the rumen of cattle and the nitrous oxide emissions from the fertilization of animal feed or liquid manure can also be saved in this way. “So replacing minced meat with microbial protein would be a good start to reduce the environmental damage of today’s beef production,” reports Humpenöder.

But what exactly makes the production of the microbial protein so much more environmentally friendly? While livestock farming and soy protein meat substitutes depend on the agricultural industry, the protein produced by the mushrooms can be largely decoupled from agricultural production. “Our results show that the production of microbial protein requires much less agricultural land than the same amount of protein from meat – even if you include the cultivation of the sugars that the microbes need,” explains co-author Isabelle Weindl from PIK. Because the fungal cells grow in heated bioreactors and only need sugar as the starting material. In addition, there can be no question of doing without: The harvested “mycoprotein” is of very high quality, as it is in no way inferior to animal protein in terms of amino acid content, digestibility and consistency, explain Humpenöder and his team.

Soon independent of agriculture?

Research is even being carried out to have microbial proteins produced by bacteria that do not use sugar but methane or CO2 as an energy source – these could in future represent a protein source for humans that is completely independent of agriculture. Whether with or without sugar – when shifting from animal to fermentation tank, the question of energy supply for the production process also arises: “A large-scale conversion to biotech food must go hand in hand with climate-friendly power generation. Only in this way can the climate protection potential be fully effective,” explains senior author Alexander Popp from PIK. “But if we get it right, microbial protein can make transition easier for meat lovers, too. Even small bites can make a big difference.”

Source: Potsdam Institute for Climate Impact Research; Specialist article: Nature, doi: 10.1038/s41586-022-04629-w

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