Starbucks turns food waste into plastic

In Hong Kong, Starbucks is funding a new biorefinery to process its coffee grounds and any leftovers from its bakery.

New technology in Hong Kong could address the issue of food waste while providing a sustainable supply of bioplastics. Starbucks Hong Kong has invested in the development of new biorefinery technology which converts food waste into succinic acid, a key chemical in the manufacture of high-value products such as plastics and detergents. Carbohydrates in the food are broken down by fungal enzymes into simple sugars, before bacterial fermentation – of which succinic acid is a by-product.

Hong Kong produces over 3,200 tonnes of food waste every day, the majority of which is incinerated or placed in landfills. Processing this waste in a biorefinery would not only reduce reliance on environmentally damaging methods of disposal, but could also offer a sustainable alternative to the petroleum products currently used in the manufacture of plastics – while at the same time consuming CO2 in the fermentation process. What’s more, these bioplastics are completely biodegradable.

Leading the research is Dr Carol Lin, a mechanical engineer at City University of Hong Kong. Last summer, she was approached by Hong Kong-based non-profit The Climate Group about the possibility of developing a biorefinery to process coffee grounds and bakery waste from Starbucks, one of its corporate members. In addition to providing this waste, Starbucks helped fund the research by donating a portion of proceeds from its ‘Care for our Planet Cookies’ gift sets.

The Climate Group intend to show that research and collaboration among thought leaders can bring innovations like this to a local market, without the need to wait for global markets to transform.

“The technology promises a local-scale solution to a local resource issue”, the Group says, “allowing city-level incentives and regulation to play a part in boosting local business opportunities.”

Lin’s team has already successfully mastered the process in the lab and, by next year, hopes to have set up a pilot plant. The next step will be to work on the logistics of collecting the waste and transporting it to the plant, though she points out that within a city economy like Hong Kong’s, feedstock and markets for the products can be co-located, reducing long supply chains and transport costs. Lin is certain that the technology is commercially viable, but large-scale adoption is still dependent on funding.

The question begs, could companies like Starbucks do more to reduce their food waste in the first place?

Dan Crossley, Principal Sustainability Advisor at Forum for the Future, warns against a culture of waste-dependency. “If pilots are scaled up, the thing we should guard against is getting locked into a whole new set of infrastructure that relies on steady streams of waste”, he says. – Annabelle Bladon

Photo: Astrid & Hanns-Frieder Michler/Science Photo Library