Canadian scientists have created a biodegradable material from fish droppings

Canadian scientists say the normally wasted heads, bones, skins and guts of fish can be converted into a useful substance that can replace the crude polyurethane from petroleum. They are used in everything from shoes and clothes to refrigerators and building materials. The polyurethane contained leaves a large carbon footprint and decomposes very slowly in nature.

A team of scientists from Memorial University in Newfoundland, led by Francesca Carton, found that fish oil-based plastics could provide an environmentally friendly solution while processing fish processing plant waste.

Previous studies have developed methods for making plastics from fish waste, but recent research goes further to discover how easily this material can biodegrade at the end of its useful life.

To create the new material, researchers used oil extracted from salmon chunks left over after slicing meat intended for human consumption. First, they added oxygen to the oil in a controlled environment to form epoxy – molecules similar to those found in epoxy resins. Then they added carbon dioxide to the epoxies and combined the resulting molecules with nitrogenous hydrocarbon derivatives to form a new polyurethane-like substance.

“It is important that we start manufacturing plastic materials that have expired their useful lives, whether it’s chemical decomposition, which turns the material into carbon dioxide and water, or recycling and other uses,” said Kirton. “At the beginning of the fish oil process, the faint smell of fish remains, but as we go through the following steps, the smell disappears,” she added.

Since last summer, the team has modified this process to simplify and speed up the degradation of fish oil plastics. Experiments indicate that new materials can be easily decomposed as needed. In one experiment, scientists soaked some bits of fish plastic in water and added lipase to some – an enzyme that breaks down fats in fish oil. Under a microscope, the researchers saw microbial growth in the samples – including those that only existed in plain water. According to the team, the results indicate that the new material could easily degrade.

Kerton and his colleague Mikhaileya Wheeler now intend to focus on the potential use of the new material, for example in the form of packaging or fibers for apparel fabrics. “I find it interesting how we can take some of the waste that people usually throw away and make it not only something useful, but also something that could change the way plastic is made,” Wheeler said.

Polyurethane is traditionally produced with the help of oil and phosgene, which is a toxic gas. This process produces isocyanates that irritate the eyes, the digestive system, and the respiratory system, which has been linked to severe asthma attacks. In addition, the final product does not degrade easily in the natural environment and the limited biodegradation that occurs may lead to the release of carcinogenic components.