Scientists from Yokohama National University (YNU) have analyzed whether used coffee grounds can be used to make a form of bioplastic.
The research was led by associate professor Izuru Kawamura from the Graduate School of Engineering Science, and recently published in the Cellulose journal on April 1st.
Earth’s most abundant organic compound is cellulose, and coffee grounds are full of it. Cellulose nanofibers from used coffee grounds account for almost half of the volume of weight. Kawamura points out that, up to this point, cellulose nanofibers have mainly been produced from wood-based materials. But, this study shows spent coffee grounds are a promising raw material.
Kawamura explains what the team hopes to accomplish from this research:
Our ultimate goal is to establish a sustainable recycling system with our cellulose nanofibers in the coffee industry. Now, more and more restaurants and cafés have been banned from using single-use straws. Following that movement, we aim to make a transparent disposal coffee cup and straw with an additive comprising cellulose nanofibers from spent coffee grounds.
The researchers performed experiments that included catalytic oxidation, where the cellulose nanofibers are separated from the cell walls of coffee beans. They also performed various imaging methods such as x-ray diffraction, electron microscopy, and thermogravimetric analysis. This was done to compare the cellulose nanofibers in the beans to those found in wood.
Their results showed that the coffee ground-based cellulose nanofibers can be successfully combined with polyvinyl alcohol to make a variety of consumer and industrial products. Polyvinyl alcohol is commonly used to make biodegradable plastics.
This is good news because people drink a lot of coffee. According to the International Coffee Organization, more than 6 million tons are produced worldwide every year. The majority of spent coffee grounds end up being thrown in the garbage.
Some people do save coffee grounds to generate more nutrient-rich soil, but this could be a very good way to monetize used coffee grounds for bioplastic and help the environment.
Kawamura thinks that aside from coffee grounds, cellulose nanofibers, in general, can be used for so much more, including the automotive industry. By supplementing cellulose for steel it can help lower vehicle emissions.
The total weight of plastic resin made by cellulose nanofibers is very light compared to steel. It will bring an efficient reduction of CO2 emission.
The team plans to do further research and testing to develop a commercially feasible process for the used coffee grounds, but this is an exciting first step to help rid the world of harmful plastics.
