Spider Farming Is No Fun. Make Yeast Do the Work
SPIDERS ARE NOT the easiest creatures to farm. Sure, you have the occasional tourist stop silk farm or pet spider breeder, but farming spiders—especially venomous web-building ones—on an industrial scale like chickens? Nope.
OK, you might ask, what could you possibly want to do with so many venomous spiders that is not nefarious? Spider venom is actually chock full of different proteins—some of which can, yes, kill you, but others that can be turned into drugs or insecticides. In other words, spider venom is damn useful. But milking a spider gets you only a thousandth or a hundredth of a milliliter of the stuff. The problem is getting enough of it.
That’s where synthetic biology comes in. Instead of milking spiders for venom, scientists can take the gene for a venom protein of interest and stick it inside yeast. The yeast act as little venom protein factories, and they grow and grow without fuss inside a vat. No spiders needed!
Michigan-based Vestaron uses this technique to make insecticides. “Spiders are the best insect predators in the world,” says Glenn King, who founded the company in 2006. Any single venom might have hundreds or thousands of different proteins, all with different properties. Vestaron uses a protein from the Australian Blue Mountain funnel-web spider for its venom-based insecticide, the first such product to get approval from the Environmental Protection Agency in 2014.
The company is now developing a whole slate of insecticides by screening venom. Conventional chemical insecticides generally work by shutting down the molecular machinery of insects in one of five different ways, and Vestaron is looking for venom-based alternatives for each mechanism. The upside is that these pesticides are safer and don’t linger as long in the environment. And at a time when the EPA is increasingly concerned about bees, Vestaron’s product does not appear harmful to them either.
The downside, though, is cost. “Our challenges are around how do you make something this intricate pennies per gram to spread over acres of crops,” says Bob Kennedy, Vestaron’s chief scientific officer. That’s why Vestaron is marketing its product to greenhouse growers, whose vegetables fetch higher profit margins than commodity crops like corn or soybeans. So what about marijuana, a plant often grown indoors with, ahem, very high profit margins? Kennedy demurred because federal drug laws make it impossible to get pesticides approved for use on marijuana—but you can draw your own conclusions.
What has even higher profit margins though? Pharmaceutical drugs. King, who is no longer involved with the day to day at Vestaron, runs a lab at the University of Queensland in Australia, where he looks for spider venom proteins that can treat disease. His lab houses a collection of 500 spider venoms. (It is literally a lab staffer’s job to travel the world milking spiders.) Once they’ve found a promising venom protein, they also use synthetic biology to stick the gene into bacteria, manufacturing the protein at scale to study it more closely. King says his lab now has promising candidates to treat a form of epilepsy (from a Togo starburst tarantula) and stroke (from another Australian funnel-web spider).
And it’s not just the spider’s venom that can be valuable. The startup Bolt Threads is using yeast to make spider silk, a material whose wonder properties are better known than venom’s. The company’s scientists grow genetically modified yeast that manufacture silk protein in a huge vat; the protein is then extruded as thin threads of silk. “Yeast are industrial powerhouses that people have been using for over a thousand years to make beer, wine and bread,” says Bolt CEO Dan Widmaier. Indeed, humans domesticated yeast millenia ago for their products (alcohol, bubbles) in the same way they domesticated sheep for their wool or cows for their milk.
Spiders present, let’s say, some unique challenges. But with synthetic biology, our modern farmers don’t need to domesticate spiders for their products anymore. Scientists have also figured out how to get yeast to make vanilla flavor and rose oil and opioids—all originally derived from plants— potentially unchaining these products from agriculture. The challenge now is making them cheaply enough to compete on the market.
Don’t expect a vat of yeast to lay a whole egg soon (or ever?!), but domesticating animals and plants has long been how humans have reshaped nature for their convenience. Synthetic biology is the next link in the chain.