Humans have long excelled in manipulating their environment to increase the amount of food the ecosystem produces, from burning undergrowth to fruit cultivation or damming a streams to create fishing ponds. The most extreme form of this survival strategy is farming crops, where people rebuild the entire ecosystem to serve the needs of several edible plants. Over the past century, farmers have taken this strategy even further by using chemicals to improve nutrient uptake and pest control for our crops.
Under this system of industrial agriculture, cereal production increased from 800 million to more than 2.7 billion tonnes between 1961 and 2019, outpacing current human population growth. However, this success has entailed significant environmental costs. About half of the world’s surface is now used for agriculture, half of all biologically usable nitrogen is produced artificially, and 96 percent of mammalian biomass is made up of either humans or our cattle. The result has been mass extinctions and climate change, with agriculture responsible for about 25 percent of total global warming.
The ideas for reforming agriculture to make it less destructive vary widely, from organic farming and eating less meat to genetic engineering of crops to make them more productive and less prone to pests. Replacing animals with laboratory-grown meat is even on the table.
Over the last five years, a more radical idea has emerged: the cultivation of hydrogen oxidizing bacteria for human consumption. These bacteria consume hydrogen for energy and carbon dioxide for biomass production. The plan is to combine existing technologies of water electrolysis, bacterial fermentation and atmospheric carbon dioxide capture in order to grow huge amounts of bacterial biomass using renewable electricity, which will essentially translate the ecosystem modification strategy. This means that people take responsibility for capturing sunlight to distribute water and grow food in a completely artificial environment.
The resulting edible biomass is a yellow powder rich in protein that is said to taste like wheat.
The substance could replace raw materials needed for livestock production or fillers in common food products; they can be building blocks for artificial meat, milk and eggs or a flour substitute in pancakes or pasta.
This food production system – commonly referred to as “bacilliculture” – has a number of advantages over traditional agriculture.
It is remarkable that even in its early stages of development, bacilliculture is much more efficient than agriculture in converting solar energy into usable calories. As a result, supplying the world with bacilli would require only about 2 percent of the land currently used for crops. Likewise, the water needed for bacilliculture would be only about 20 percent of the water used to grow crops. While bacilliculture still requires synthetic fertilizer production, the bioreactor environment in which cultivation takes place would mean that nutrient outflow could be much more easily controlled. The commercialization of this technology is ongoing; The Finnish company Solar Foods promised a functioning factory by 2023.
It is possible that bacilliculture will never catch on, or only in very special circumstances, such as a long-term space travel in which case it will have no impact on climate change. At the other end of the spectrum, it could completely displace agriculture and become the primary food source for humans and domesticated animals.
Bacilliculture requires a lot of electricity, but the balanced cost of new solar energy on a utility scale is now only 3.6 cents per kilowatt hour and is falling. This means that the estimated electricity costs for producing a kilogram of biomass are similar to the market costs for a kilo of soybean.
In idealized experiments using a global climate model, we found that if agriculture was abruptly abandoned in 2020, the warming effect of the non-fossil fuel component of climate change in agriculture has dissipated in half in 30 years and 250 years in all. In principle, therefore, the widespread introduction of bacilliculture could reverse much of the climate change caused by agriculture.
The idea of eating bacteria is probably not particularly tempting for many. If bacterial biomass became a very popular food, high protein content and relatively low carbohydrate and oil content would limit how much you could eat daily without gout or other health problems, although over time, these limitations can be removed through genetic engineering.
Abridged from the main article that was published in Bulletin of the Atomic Scientists.