The blue crab is an invasive species that is invading the ecosystem stretching from Nova Scotia (Canada) to California (USA), but scientists have just found an unexpected benefit from this pest, that is the source of raw materials for making biodegradable plastics.
Scientists from Canada plan to crush crab shells, purify and extract super-strong chitin polymers. Chitin, found in crustaceans and insects, can be used to create a biodegradable bioplastic. This project is like an “arrow kill two terns”: reduce the number of invasive species and create an alternative to plastic.
McGill University chemist Audrey Moore is running the project, in collaboration with Nova Scotia’s Kejimkujik National Park, to make plastic cups and plastic utensils from the blue crab swarm.
“Working with Kejimkujik is a big challenge ”, Mr. Moore Moore said. “We have to get out of the lab and into the real world to see if this really works.”
This is not the first time a thing like this has been proposed. Laboratories from Scotland to California are doing similar projects, all hoping to exploit chitin to make plastics. However, going from crab shell to fork knife is not an easy task.
In many laboratories, scientists use toxic chemicals such as hydrochloric acid to purify chitin, then add more chemicals to turn chitin into chitosan, a material that can be used to make plastics. Although cleaner than producing plastic from petroleum products, this process produces a lot of polluted wastewater that is not good for the environment.
Moore’s lab specializes in green chemistry and is trying a new approach. Instead of dissolving the crab shell in acid, Moore mixes the crushed crust with another powder, which requires less water and produces much less waste. The results of this study were published in Green Chemistry in March 2019.
“When you think of chemistry, you often think about mixing liquids. But we realized that you can do a lot of good chemical reactions during the solid phase. ”
Of course, this is still just the beginning. Moore must check to make sure that the new plastic actually breaks down in the natural environment. She also wants to expand the production scale, will need more crabs. Fortunately, there is no shortage of blue crabs and conservationists across Canada want them to disappear. The first batch of crab will be shipped to McGill this spring. Eventually, Moore hopes to build a small facility to crush crabs in place, making it easier to transport high quantities back to her lab.
In Kejimkujik, blue crabs have been depleting eelgrass and clam populations since the 1980s. Grass seems to be an unimportant conservation goal, but the seagrass ecosystem is one of the ecosystems. The most diverse in the world. Eel grass helps stabilize, move sediment of the ocean floor and provide oxygen, habitat for many marine creatures, including young fish. They are an important feeding ground for many migratory birds and provide a surface for algae to grow.
Not only that, blue crabs also destroy wherever they go. Their populations are explosive, dominant or will eat native invertebrates. As climate change warms our waters, invasive species like blue crabs are becoming more common, invading more ecosystems.
This makes it worse for another serious problem: every minute, we dump a dump truck into the ocean. The plastic got caught in the intestines of seabirds and turtles, wrapped around dolphins’ necks, or strangled the fish. Moreover, the toxic chemicals plastic can be toxic to many marine creatures.
Bioplastics have long been billed as a potential solution to this crisis, but Moore’s lab takes science one step closer to reality, proving that we can make plastics in a way cleaner, more green.