Let’s focus for a moment on technology. Specifically, what might be the most important environmental technology ever developed: precision fermentation.
Precision fermentation is a refined form of brewing, a means of multiplying microbes to create specific products. It has been used for many years to produce drugs and food additives. But now, in several labs and a few factories, scientists are developing what could be a new generation of staple foods.
The developments I find most interesting use no agricultural feedstocks. The microbes they breed feed on hydrogen or methanol – which can be made with renewable electricity – combined with water, carbon dioxide and a very small amount of fertiliser. They produce a flour that contains roughly 60% protein, a much higher concentration than any major crop can achieve (soy beans contain 37%, chick peas, 20%). When they are bred to produce specific proteins and fats, they can create much better replacements than plant products for meat, fish, milk and eggs. And they have the potential to do two astonishing things.
If livestock production is replaced by this technology, it creates what could be the last major opportunity to prevent Earth systems collapse, namely ecological restoration on a massive scale. By rewilding the vast tracts now occupied by livestock (by far the greatest of all human land uses) or by the crops used to feed them – as well as the seas being trawled or gill-netted to destruction – and restoring forests, wetlands, savannahs, natural grasslands, mangroves, reefs and sea floors, we could both stop the sixth great extinction and draw down much of the carbon we have released into the atmosphere.
The second astonishing possibility is breaking the extreme dependency of many nations on food shipped from distant places. Nations in the Middle East, north Africa, the Horn of Africa and Central America do not possess sufficient fertile land or water to grow enough food of their own. In other places, especially parts of sub-Saharan Africa, a combination of soil degradation, population growth and dietary change cancels out any gains in yield. But all the nations most vulnerable to food insecurity are rich in something else: sunlight. This is the feedstock required to sustain food production based on hydrogen and methanol.
Precision fermentation is at the top of its price curve, and has great potential for steep reductions. Farming multicellular organisms (plants and animals) is at the bottom of its price curve: it has pushed these creatures to their limits, and sometimes beyond. If production is distributed (which I believe is essential), every town could have an autonomous microbial brewery, making cheap protein-rich foods tailored to local markets. This technology could, in many nations, deliver food security more effectively than farming can.
There are four main objections. The first is “Yuck, bacteria!” Well, tough, you eat them with every meal. In fact, we deliberately introduce live ones into some of our foods, such as cheese and yoghurt. And take a look at the intensive animal factories that produce most of the meat and eggs we eat and the slaughterhouses that serve them, both of which the new technology could make redundant.
The second objection is that these flours could be used to make ultra-processed foods. Yes, like wheat flour, they could. But they can also be used to radically reduce the processing involved in making substitutes for animal products, especially if the microbes are gene-edited to produce specific proteins.
This brings us to the third objection. There are major problems with certain genetically modified crops such as Roundup Ready maize, whose main purpose was to enlarge the market for a proprietary herbicide, and the dominance of the company that produced it. But GM microbes have been used uncontroversially in precision fermentation since the 1970s to produce insulin, the rennet substitute chymosin and vitamins. There is a real and terrifying genetic contamination crisis in the food industry, but it arises from business as usual: the spread of antibiotic resistance genes from livestock slurry tanks, into the soil and thence into the food chain and the living world. GM microbes paradoxically offer our best hope of stopping genetic contamination.
The fourth objection has more weight: the potential for these new technologies to be captured by a few corporations. The risk is real and we should engage with it now, demanding a new food economy that’s radically different from the existing one, in which extreme consolidation has already taken place. But this is not an argument against the technology itself, any more than the dangerous concentration in the global grain trade (90% of it in the hands of four corporations) is an argument against trading grain, without which billions would starve.
The real sticking point, I believe, is neophobia. I know people who won’t own a microwave oven, as they believe it will damage their health (it doesn’t), but who do own a woodburning stove, which does. We defend the old and revile the new. Much of the time, it should be the other way around.
I’ve given my support to a new campaign, called Reboot Food, to make the case for the new technologies that could help pull us out of our disastrous spiral. We hope to ferment a revolution.
- George Monbiot is a Guardian columnist
Article in Survival Tech Club
Microbes can be used as tiny factories to produce useful biomolecules for our humankind. We can instruct the microbes to produce a wide range of different kinds of substances, like proteins and fats. The instructions are given to the microbe in the language of biology, DNA.
This concept is interchangeably referred as microbial cell factories and precision fermentation. For the sake of consistency, I’ll use the term precision fermentation.
In Microbes: Part 2, we learnt about climate startups that are using microbes to produce a variety of more sustainable products like animal-free dairy-products, coffee, and chemicals. It’s important to note that not all those startups are using precision fermentation as their underlying technology. Here’s a list of those startups that are for sure using precision fermentation:
This week I discovered that a Munich-based startup, QOA, makes chocolate via precision fermentation! QOA raised recently a $6M seed round.
Let’s start with the big picture and examine how a compound can be produced with microbes. With a compound, I mean proteins, chemicals, polymers, and natural products like fragrances and flavors.
There are four steps in a (simplified) precision fermentation process:
- Engineer the microbe that can produce your desired compound
- Grow the microbes (in a fermentor, a closed tank similar to what we use to make beer and wine)
- Harvest and purify the compound from microbes
- Eat or use the compound!
The photo below by The Good Food Institute illustrates the basic steps of producing animal protein via precision fermentation. As you can see, engineering a microbe involves genetic engineering. We give the production instructions to the microbe (here production organism) in the form of a gene. The gene is typically from an organism that naturally produces the desired compound (here animal protein).
This all sounds like magic! But how exactly actually does the science work? In the next sections, I’ll go through the four steps of precision fermentation.
The first step is to engineer the microbe to produce the compound that we want. We can achieve this is by modifying the microbe’s metabolism. The scientist call this step as strain development.
Before we dive into modifying the microbe’s metabolism, let’s first understand what metabolism is.
Metabolism is a network of chemical reactions that keep organisms like microbes and humans alive.
The three main purposes of metabolism are to:
- convert food/fuel to energy to run cellular processes
- convert food/fuel to building blocks for proteins, lipids, nucleic acids, and some carbohydrates
- eliminate metabolic wastes
All these purposes are achieved through a number of metabolic pathways. To understand how a metabolic pathway looks like, let’s check out the energy metabolic pathway of a yeast cell.
The yeast cell (like we humans) requires energy to function. Yeast gets its energy from glucose. When yeast then breaks down glucose, it releases energy to its cellular functions. (If you want to learn more about the cellular energy called Adenosine Triphosphate (ATP), watch this Youtube video.)
Yeast’s special talent is that extract energy from food also in the absence of oxygen! As a result, ethanol and carbon dioxide get produced as by-products. This is the exact metabolic pathway that we humans have harnessed for years to make bread and beer.
In reality, the metabolic pathways are more complex. A metabolic pathway is a series of chemical reactions that all take place in a careful order. The below graphic shows the same energy metabolic pathway of a yeast cell, but in more detail.
Notice how glucose gets transformed into a number of other molecules before it ends up as ethanol and CO2. Also, notice how all the steps from one substrate into another are catalyzed by specific enzymes (e.g. Glk1, Pgi1, Pfk 1/2). (I need to do a separate deep dive on enzymes!).
This energy metabolic pathway is just one metabolic pathway of the 1500 pathways that a yeast cell has. So expect complexity when engineering these pathways…
Now that we are more familiar with metabolism and metabolic pathways, let’s see turn to metabolic engineering.
Metabolic engineering allows us to tweak the metabolic pathways of microbes so that they will produce the compounds that we find useful (e.g. casein protein for animal-free dairy products, or palmitic acid for palm oil).
I let Prof. Jens Nielsen from Chalmers University explain how metabolic engineering is done for a yeast cell. Watch especially the part 3:25-8:30.
(Btw I love the both iBiology Techniques and iBiology Youtube channels!)
Engineering the microbe is inarguably the biggest challenge in precision fermentation. As Jens explained in the video, it takes usually numerous iterations to engineer a microbe that produces enough of the compound that we want.
If you want to have a real deep dive into this topic of strain development, I can highly recommend reading this open-source scientific article. It’s a heavy, but fascinating read!
The second step is to grow the microbes via a process called fermentation.
Microbes are like humans; they need adequate food (nutrients) and suitable environment (temperature, pH etc.) to grow and flourish! These parameters are way easier to control in a closed setting. That’s why microbes are grown in a fermentor, a large closed tank.
I found this great video series about fermentation on Youtube. Watch especially the part 2:23-6:12.
The third step is about harvesting and purifying the compound.
In precision fermentation, we don’t want the whole microbe, but rather the compound that its engineered metabolism has produced. The following video (0:30-4:08) explains well how the product is harvested from the microbes.
Next, it is time to clean the product from any other substances that may be attached to it. This is explained on the video at 1:20-5:26.
Finally, this microbial production process is done!
Huge thanks to my amazing friend Minea Saikkala, molecular bioscientist for reviewing this article!!
I know there’s been a lot to learn already in this article. However, those who fell in love with the concept of precision fermentation, can find further resources below:
This was a wild learning curve for me about precision fermentation. I hope that this post gives you the resources to help understand this fascinating and impactful technology.
If you liked this article, share it with your fellow human beings!💚
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- Faria-Oliveira et al. (2015). The Role of Yeast and Lactic Acid Bacteria in the Production of Fermented Beverages in South America, Food Production and Industry, Ayman Hafiz Amer Eissa, IntechOpen. Link.
- The Good Food Institute (2018). Cellular agriculture: An extension of common production methods for food. Link.
- Ko et al. (2020). Tools and strategies of systems metabolic engineering for the development of microbial cell factories for chemical production. Chemical Society Reviews, 49, pp. 4615-4636. Link.
- Libre Texts, Chemistry (2021). Energy Metabolism. Link.
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