Why fruit flies?

Why fruit flies?

For the past 18 months, we’ve skirted around public and private discussions of our technology as we worked through the patenting process. This week, Future Fields is thrilled to publicly launch the EntoEngine platform — our patent pending process for using Drosophila melanogaster (the common fruit fly) to sustainably produce growth factors at mass-market cost and scale for the cellular agriculture industry. This is the story behind our technology that started our path through uncharted scientific territory, as told by founder and CTO Matt Anderson-Baron.

Throughout my time in grad school, I grew increasingly jaded with many aspects of academia. Although I enjoyed my research and learning from people much smarter than myself, I was frustrated by a system that rewarded publications over tangible benefits to society. Starting a company was the farthest thing from my mind when I started my PhD — but I was energized by the idea of working on something with a real world impact. In 2018, over many beers and conversations where similar frustrations and worries about the state of the world were shared, Future Fields was officially born.

The company we started three years ago looks very different from the company we are today. At its inception, we were a cell-based meat company focused on poultry products. I was still a PhD student, and my cofounders Jalene and Lejjy were both working full-time jobs. I spent most of my days locked away in the lab doing PCR reactions, culturing cells, or counting Drosophila. I began to tinker on this side project of sorts on evenings and weekends, squeezing in experiments where I could. I established a primary cell line from a local broiler chicken that was being euthanized on the university campus. With that, I was able to start working towards a prototype — a small 20 gram chicken nugget produced by seeding said primary cells onto a decellularized piece of apple. This was meant to be a proof of concept prototype — nothing more — but it ended up changing the entire course of our company because we experienced one of the greatest pain points all cell ag companies have: cell growth media is bloody expensive. It took buckets of growth media to make this little chicken nugget. We always knew that the cost of growth media would be a challenge, but that chicken nugget highlighted the immensity of the challenge. We decided to focus on making a more cost-effective growth media to solve this problem for ourselves. Fast forward a year and one pivot later — that is now our company’s mission: to unleash the full potential of cellular agriculture. We know we have a greater impact by making growth media more cost-effective for all the incredible companies out there.

When we began to look at addressing growth media costs, it was obvious that serum-supplemented media typically used by cell biologists was not an option. The challenge was (and still is) that serum-free growth media is plagued by costly growth factors. Using the GFI’s report on cell culture media as a starting point, it became clear that if we wanted to reduce growth media costs, we’d have to tackle the high cost of growth factors. Growth factors are proteins, which means they’re produced recombinantly by inserting the gene for a particular growth factor into an expression host. In essence, hijacking the cellular machinery of the host to produce the protein of interest. We quickly discovered that traditional expression systems like E.coli, yeast, or mammalian cells were not going to cut it. The cost reduction required to make growth factors for cell ag were just not feasible with existing systems. We knew that a truly groundbreaking approach was needed.

So the story goes: my wife (and cofounder) Jalene and I were standing in line at the campus Tim Horton’s discussing this problem. Jalene made an off-the-cuff remark along the lines of: “Why don’t you just use fruit flies to replace FBS?”. Jalene, having no formal scientific background, knew that I worked with Drosophila during my PhD work and had heard enough of my seminars to know that they were a great model organism for disease-based research. It was an interesting thought, but at the time, the approach felt unclear. After sitting on this idea for a few more months, my mind began to wander back to the issue of costly growth factors. I wish I could say there was a eureka moment but there wasn’t. At some point, my mind just married those two ideas: fruit flies and growth factors. What started as a seed of a thought, percolated into a myriad of ideas and experiments. Drosophila are elegant molecular machines designed by nature and one of the most well-studied organisms on the planet. Why not harness the power of this system to create more cost-effective growth factors and unlock the immense benefits of the cell ag production? They’ve been used as a model organism in biological research for over a century, when Thoman Hunt Morgan first started culturing them in 1910. The scientific legacy of Drosophila is rich, including six Nobel prizes. Because of this history, an extensive array of genetic tools are available.

The Drosophila system is like the swiss army knife of genetics. Many well-established protocols are available for their genetic modification. We harness this tool to produce any growth factor needed for the cell ag industry. With our system, we can create stable stocks that produce each growth factor in perpetuity. Rather than relying on viral vectors that require continual inoculation for production, like some other insect systems, we can create stable strains for each growth factor. One of the greatest things about this industry is the wide variety of products to be made. But, in order to do that, it’s important to produce those same products with species-specific growth factors. Pork products should be produced with porcine growth factors, beef products with bovine growth factors, etc. A wide variety of products require a wide variety of inputs. The Drosophila system is flexible and agile enough to produce species-specific growth factors for every type of cell ag product. Moreover, growth factors are complex proteins, often requiring multiple posttranslational modifications (science talk for small additions or modifications to the protein after it’s synthesized) for bioactivity. The cellular machinery of insect cells is well-equipped to facilitate these modifications, unlike its E.coli or yeast counterparts, which lack many of the necessary enzymes.

We knew that Drosophila could produce the growth factors that we needed — but that alone wasn’t a good enough reason to use them. The real superpower (amongst many others) of the Drosophila system is that, with the right innovations, they’re incredibly cheap and easy to rear. While we faced some challenges early on, our team has developed some truly innovative methods that allow us to rear Drosophila much cheaper than growing cells in a bioreactor (yes, even E.coli). Existing cell-based systems require costly bioreactors (a 20,000L bioreactor can cost over $250,000) that are even more expensive to operate. Drosophila do not have these large operation costs and require only modest environmental controls to ensure optimal rearing. Not to mention, cell-based systems require growth media themselves. Even for cheaper systems, like E.coli, these inputs add up. In contrast, Drosophila can feed on organic side streams and byproducts from other processes (i.e. organic waste). In fact, insects are some of the most efficient organisms at converting nutrients into biomass.

Another factor we considered was the environmental impacts of our production system. One of the greatest benefits of the cell ag industry is the opportunity to create a more sustainable source of protein for a growing population. It compromises the mission of the industry if the supply chain pulls back in many of the unsustainable elements of traditional protein production. Over 20% of the energy requirements for recombinant protein production using a fed-batch bioreactor go to the operation of the production bioreactor*. Water production for these systems represents over half of the energy requirements* and the water usage for these systems is immense. An average antibody production operation utilizing mammalian cell hosts uses anywhere from 1.1–1.6 million liters of water per year, depending if they use a fed batch or perfusion bioreactor, to produce just 28 kg of recombinant protein*. In contrast, Drosophila get all of their hydration from their food. There’s no need for an additional source of water. The copious volumes of cell culture waste that would otherwise be generated from cell-based expression systems would cause significant challenges to deal with, particularly at large scale. You can’t just dump 20,000 L of E.coli culture down the drain. Cell culture waste needs to be sterilized (with chemicals like Virkon) before they can be disposed of. At large scale, this is incredibly cumbersome to deal with and poses serious environmental threats to surrounding ecosystems. Drosophila waste, on the other hand, can be upcycled to usable products. Insect frass (residual biomass from pupal casings and feces) is an effective crop fertilizer. Residual insect material leftover after the purification process can also be refined into useful material, such as chitosan. The environmental benefits of utilizing Drosophila were strongly considered in moving forward with this system. At full scale production, we are committed to creating a completely closed loop system with our expression platform.

The decision to utilize the Drosophila system was not made lightly. We looked long and hard at traditional systems. There are simply too many challenges to address in a reasonable amount of time. In an ideal world, living things are removed entirely from human food production. But we don’t live in an ideal world. The climate clock is ticking. I’d like my daughter, who’s never been to a grocery store or hugged another kid, to avoid a lifetime of zoonotic pandemics. We feel a moral imperative to do whatever we can to unleash cellular agriculture and push the resulting paradigm shift today. Now more than ever, time is of the essence. Just as we continually hear that we must “bend the curve” to reduce the spread of COVID-19, so too must we bend the climate change curve. If the urgency demands that we deploy Thomas Hunt Morgan’s legacy at scale to save billions of cows, pigs, chickens, and humans from the harms of an unsustainable future, then we will rise to the challenge. Cell ag represents a new and brighter future for global food production, the humble fruit fly is ready to help usher it in.

*Bioreactor data from: Bunnak et al. Life-Cycle and Cost of Goods Assessment of Fed-Batch and Perfusion-Based Manufacturing Processes for mAbs. (2016) Biotechnology Progress. 32, (5).