Fruit flies: the next generation of bioreactors
Artwork by Jane Hyde
March 02, 2023

Fruit flies: the next generation of bioreactors

For the longest time, fruit flies were to me the start of my scientific career. I cut my research teeth on Drosophila melanogaster, as the fruit fly is officially known, as an undergraduate at Grand Valley State University (GVSU) in west Michigan. They were also an organism I swore I never wanted to work with again when I graduated. 


It’s not that I disliked the flies themselves. I enjoyed learning how to modify their genomes and, later, painstakingly dissect brains from larvae so that I could assess expression patterns of a fluorescent marker. But as a lowly undergraduate student, I also was in charge of keeping the flies happy and well fed. And, to put it bluntly, their food stank. I never wanted to spend hours of my life each day enveloped by that smell again.


My resolve to never work with them again didn’t last too long; less than a year after graduating from GVSU I found myself as a graduate student at Baylor College of Medicine in Houston rotating through a Drosophila research lab. This time, I was studying the impact of bacterial infection on the flies’ ability to respond to pain, as judged by the way they moved (or didn’t) when I touched fly larvae with a hot metal rod. Morbid, I know. I didn’t end up joining the lab for my thesis work; instead, I dedicated myself to studying the microbiome and left flies in the dust, for good this time.


Or so I thought.


After spending 7 years researching the microbiome, including 2 years managing a citizen science research project, I tired of academia and decided to make a more immediate impact on the world: providing people with responsible scientific reporting. If there’s one thing I learned managing a citizen science project, it’s this: people find weird information and believe it. I wanted to help dilute out the crap by writing good stuff. So in 2018 I left academia and began science writing full time.


I’ve talked to dozens of incredibly bright and motivated people and learned a lot of interesting science I never would have had I stayed in my microbiome bubble. Recently, while writing a byline for a Forbes column,I learned about one of the coolest scientific applications I’ve heard about for quite some time: using fruit flies to make an assortment of useful proteins.


Yup, the flies are back! I just can’t seem to escape them.


But what the company called Future Fields is doing is pretty darn cool. Most proteins, from therapeutic ones like insulin to the protein used to make lab grown meat, are done so using one of three main cell types: bacteria, yeast, or hamster ovary cells. All of these cells are modified to produce some protein of interest, and they are grown in giant bioreactors in order to make enough protein to meet market demand. That means they need a LOT of food—which for these cells, comes in the form of growth factors. The entire process is expensive, uses a lot of energy (bioreactors run on electricity), and uses a lot of growth factors, which have to come from somewhere. Often, that somewhere is cows.


The company’s CEO, Matt Anderson-Baron, realized first hand the problem with bioreactors when he was trying to make his own lab-grown chicken nuggets. But instead of giving up, he came up with a new idea, and it was an ingenious one. 


Why not make proteins in fruit flies?


Indeed, why not? We know a lot about their genetics and a number of tools are available to modify their genomes. Think of all the space and energy that can be saved by turning a tiny fruit fly into a bioreactor. That’s exactly what the team at Future Fields has done. It wasn’t easy (anything that’s worth it isn’t) and took a few years for them to figure out how to not only get fruit flies to make proteins “on demand” but also how to purify those proteins from the flies. But they did. And now the possibilities are endless.


Of course, it will take some time for the industry as a whole to switch over from the tried-and-true and familiar cell lines to fruit flies—and it’s unlikely that fruit flies will fully replace bioreactor-based systems entirely. Future Fields can still make the process cheaper and more sustainable, though. How? By making growth factors with their fruit flies and distributing those growth factors to companies and organizations using cell lines. And eventually, as more and more catch on to the benefits of using fruit flies to make proteins instead of cell lines, Future Fields’ fruit flies will start making things like the next cancer therapeutic.


I told you it was an ingenious idea.


As a microbiologist studying the microbiome, I used to look at human beings and imagine wearing “microbe-vision” glasses to envision the world of microbes that comprise all of us. Now, whenever I see a fruit fly hovering around some fruit in my kitchen, I won’t just think back to my very first research project. Instead, I’ll see a miniature bioreactor flying around, full of amazing scientific potential. Much like I saw a tapestry of microbes painting every human body, I’ll see a tapestry of proteins that are poised to change the world.