Scientists have discovered a substance found in the shells of crustaceans and the limbs of insects that has the potential to become a large-scale, environmentally friendly alternative to plastics, replacing many types of plastics.
This substance is called chitosan, a type of chitin with excellent toughness. Chitin is a hard polysaccharide found in the shells of crustaceans. The Wyss Institute for Biologically Inspired Engineering at Harvard University states that chitosan is "the second most abundant organic material on Earth."
Javier Fernandez, one of the lead researchers on the study, said that after the Weiss Institute published the findings, many companies contacted them to learn more about the commercial possibilities.
According to data from the Weiss Institute, humans produce 34 million tons of plastic waste every year, with a recycling rate of only 7%, and the remaining 93% ends up in landfills and oceans. Plastic in landfills takes 1,000 years to decompose, while approximately 100 million tons of plastic waste drift in the oceans globally.
"We have a mass-producible manufacturing method that allows us to use cheap and large quantities of chitosan-based bioplastics to replace traditional plastics for industrial and commercial applications, and that is indeed feasible," the director of the Weiss Institute said in a statement.
Fernandez says a simple beverage cup can be made from 200 grams of shrimp shells, about the size of a palm. Copepods, crustaceans the size of planktonic organisms, produce billions of tons of chitin a year. "That means they produced more chitin in the past year than the world has produced in plastic bags since 2009."
There are already many bio-plastics on the market, but most are made from plant-based cellulose. Scientists at the Weiss Institute say that such bio-plastics can currently only be used to make simple food containers
Currently, it is quite difficult to mass-produce durable, complex 3D shapes from cellulose using "traditional casting or injection molding methods." Harvard scientists have only used chitosan to make cups and food containers so far, but they say that chitosan can also be used to make plastic bags, shopping bags, packaging materials, and diapers, and it is biodegradable and releases nutrients needed by plants.
Currently, the vast majority of shrimp shells are discarded, used as fertilizer, or in cosmetics and nutritional supplements.
Fernandez said that shrimp fishermen around the world, especially in Vietnam, India, and Honduras, have been searching for economical ways to process shrimp shells. Chitosan materials can generate new economic value from shrimp shell waste and are key to enabling the mass production of chitosan.
Furthermore, Fernandez added that people with seafood allergies don't need to worry about chitosan food containers causing allergies, as the allergenic part of shrimp is the muscle, not the shell. Source: Environmental Information Center(2014-05-14)
