A PhD student at Macquarie University in Sydney Australia developed novel method to convert coffee waste into biodegradable coffee cups
The process involves conversion of mannose, the prevalent sugar in the grounds, into lactic acid which can in turn be used to make biodegradable plastics. In Sydney alone, over 920 cafes and coffee shops produced nearly 3,000 tones waste coffee grounds annually. Around 50 percent of the waste material is sugar, which is ripe for reuse. The study suggest that resulting plastics have applications ranging from plastic coffee cups to yogurt containers to compost bags to sutures in medicine.
The process is inspired by an evolutionarily ancient organism Thermoplasma acidophilumis, which is single-celled organisms about a micrometer in size. The process uses a designed synthetic pathway, which sees the mannose converted to lactic acid in several steps, with different intermediate chemical compounds produced using different enzymes along the way.
In recent past, similar studies were published regarding conversion of coffee waste into plastic, which was presented by Nanyang Polytechnic in Singapore in 2017. However, this work, reliant on bacteria, was focused on local coffee preparation methods, using butter and sugar, allowing the bacteria to grow.
Other efforts have seen coffee waste converted biofuel, contributing to the running of London buses. Worldwide, the coffee industry is thought to be worth around US$100 billion, with some 500 billion cups consumed each year. It’s the second most traded commodity after petroleum. For every gram of coffee produced, 0.91 grams end up as waste, much of which ends up in landfill.