Hong Kong researcher produces biochemical from Starbucks waste

By Luke Geiver | August 22, 2012

Food waste generated from Starbucks stores in Hong Kong might hold the key for a new biobased chemical-from-waste production process method. Although most research related to food waste is focused on the use of anaerobic digestion conversion into biogas, Carol Lin, lead scientist from City University of Hong Kong, said it is not a favorable option for one of the world’s largest cities.

Although the city’s residents have a high ratio of food waste generation on a per person basis, the city doesn’t have a large amount of agricultural space for anaerobic digestion facilities, according to Lin. Because of that, along with the high cost to transport fertilizer created through the biogas production process throughout the region, “the food waste collection logistics and cost are an important issue to be considered,” Lin says.

A year ago, the head of technology from the Climate Group in Hong Kong approached Lin about the possibility of using a biotechnology-based process to tackle the issue. Lin’s answer was to use an enzymatic hydrolysis process to convert unconsumed bakery waste from Starbucks Hong Kong, a corporate member of the Climate Group.

The enzymatic hydrolysis step converts the bakery waste into simple sugars and an accessible nitrogen source. Then, she said, bacterial fermentation creates succinic acid. A downstream processing step that involves a novel resin-based ion exchange resin separates succinic acid crystals from the fermentation broth. The two fungi used in the process are Aspergillus awamori and Aspergillus oryzae.

By next year, Lin hopes to have a pilot plant built to demonstrate the process and to show the process can work in Hong Kong. “Through this research,” she said, “we found that the logistics for collecting food waste in Hong Kong is not easy.” Starbucks is helping Lin in her research efforts however, providing her team with feedstock whenever they are ready for testing. And, in April, the company started a special campaign at all of its locations to donate roughly $1 U.S. dollar for every cookie set sold, giving the donated funds to the School of Energy and Environment of City University of Hong Kong in support of research into food waste. This research, Lin added, “can solve one of the most imminent environmental issues in Hong Kong.”