New Biorefinery Could Turn Starbucks Coffee Grounds and Stale Muffins into Bioplastics

© Carol Lin, Ph.D.
Instead of throwing out (or with any luck, composting) the thousands of tons of old coffee grounds and stale bakery goods generated by coffeehouses every day of the week, what if those same substances became the raw feedstock for producing renewable biofuels or plastics? That's what a research project is setting out to explore, thanks to a collaboration between researchers at City University of Hong Kong and their neighboring Starbucks stores.

According to the American Chemical Society (ACS), the idea for applying the researcher's biorefinery technology to the wastes of a food business such as Starbucks came during a meeting between a university research team led by Carol S. K. Lin and a non-profit organization, The Climate Group. Lin was asked about using the biorefinery concept to treat the food waste products from the Hong Kong Starbucks, which generate well over 4000 tons of waste every year.

The team was already well versed in biorefineries, but addressing the food waste issue called for developing a new approach in order to build a "food biorefinery", which would produce succinic acid - a material used as an ingredient in many other products, from plastics to detergents to medicine. The new process developed by the researchers starts by blending a mixture of fungi with the baked goods and other waste, and the fungi then excrete enzymes to break the carbohydrates down into simple sugars. After blending, the mix goes into a fermenter, where bacteria convert the sugars into succinic acid.

"Our new process addresses the food waste problem by turning Starbucks’ trash into treasure — detergent ingredients and bio-plastics that can be incorporated into other useful products. The strategy reduces the environmental burden of food waste, produces a potential income from this waste and is a sustainable solution." - Lin

These food biorefineries could not only help keep food wastes out of landfills and incinerators, but because the end products can be used as a petroleum alternative in other products, these types of processes may be an important link in sustainability in the food system.

According to Lin, the new process could become commercially viable on a much larger scale with additional funding from investors, and a pilot-scale plant is being planned for a location in Germany.

Tags: Bioplastics | Technology | Waste