Coffee waste to coffee cups: Researcher harnesses potential of coffee grounds for biodegradable plastic

29 Aug 2018 --- Waste coffee grounds could be used to produce biodegradable plastics, a student from Macquarie University, Australia, has found in his Ph.D. research. Researcher Dominik Kopp developed a method to turn coffee grounds into lactic acid, which can then be used to produce biodegradable plastics.

“Australians consume six billion cups of coffee every year and the coffee grounds used to make these coffees are used only once and then discarded,” says Kopp.

However, Kopp explains, 50 percent of coffee grounds are made up of sugars, which are ideal candidates to convert into bio-based chemicals, or chemicals derived from plant- or animal-based feedstocks rather than crude oil.

“Our group is looking for new ways to convert biowaste – whether that be agricultural, garden, paper or commercial food waste – into valuable raw materials that can be used to produce high-value compounds in more environmentally friendly ways,” says Associate Professor Anwar Sunna, Dominik’s supervisor and head of the Sunna Lab which is using the rapidly growing field of synthetic biology to address biotechnology and biomedical challenges.

Using the waste coffee grounds: “We assembled a synthetic pathway to convert the most abundant sugar in the coffee grounds, mannose, into lactic acid,” Kopp explains.

“Lactic acid can be used in the production of biodegradable plastics, offering a more sustainable and environmentally-friendly alternative to fossil fuel-derived plastics. You could use such plastics to make anything from plastic coffee cups to yogurt containers to compost bags to sutures in medicine.”

Their method was inspired by a metabolic pathway that is thought to exist in an evolutionarily ancient organism, which lives in hot and extremely acidic environments.

His next step will be to further refine his conversion pathway and improve the yield of lactic acid.

“I think my project is one of many interesting approaches on how to use synthetic biology in a responsible manner for the development of a more sustainable and greener industry that doesn’t rely on crude oil,” says Kopp.

“The simple idea that we are converting waste into a valuable and sustainable product is extremely exciting.”

The University research space has spawned some exciting developments for the packaging industry, especially in terms of bio-based materials that could be potential plastic alternatives. Researchers at the Georgia Institute of Technology have created a compostable material derived from crab shells and tree fibers which, the team believes, could provide a more sustainable alternative to flexible plastic packaging used for fresh foods. While in Russia, a team at Samara Polytech created edible films consisting of only natural ingredients. The films could be used for edible packaging concepts, especially in Arctic territories, on offshore oil platforms and even during long journeys. You can read more about innovative biodegradable packaging concepts here.