Starbucks Food Waste Becomes Bioplastic Feedstock

Biorefinery Transforms Food Waste to Plastic
PHILADELPHIA, Pennsylvania, August 21, 2012 (ENS) - Starbucks is participating in a project to turn used coffee grounds and stale baked goods from its restaurants into bioplastics.

Starbucks at Avenue of Stars, Hong Kong. Credit: Michael Choi

At the national meeting of the American Chemical Society in Philadelphia Monday, a scientist from Hong Kong described her development and successful laboratory testing of a "biorefinery" that transforms Starbucks food waste into a key ingredient for making plastics.

"Our new process addresses the food waste problem by turning Starbucks' trash into treasure - detergent ingredients and bioplastics that can be incorporated into other useful products," said Carol S.K. Lin, PhD, a visiting assistant professor in the School of Energy and Environment at the City University of Hong Kong.

"The strategy reduces the environmental burden of food waste, produces a potential income from this waste and is a sustainable solution," said Dr. Lin, who leads the biorefinery research team.

The idea of turning Starbucks' food waste to bioplastics resulted from a meeting last summer between Dr. Lin and representatives of the international nonprofit organization called The Climate Group. The Climate Group asked Lin about applying her transformative technology to the wastes of one of its members, Starbucks Hong Kong.

Starbucks Hong Kong produces nearly 5,000 tons of used grounds and unconsumed waste bakery items every year.

"We are developing a new kind of biorefinery, a food biorefinery, and this concept could become very important in the future, as the world strives for greater sustainability," Lin explained.

"Using corn and other food crops for bio-based fuels and other products may not be sustainable in the long-run. Concerns exist that this approach may increase food prices and contribute to food shortages in some areas of the world," she said. "Using waste food as the raw material in a biorefinery certainly would be an attractive alternative."

Sustainable Source of Succinic Acid
At the American Chemical Society meeting, Lin described her biorefinery process, which blends the food waste with a mixture of fungi that excrete enzymes to break down carbohydrates in the food into simple sugars. The blend then goes into a fermenter, a vat where bacteria convert the sugars into succinic acid.

Succinic acid tops a U.S. Department of Energy list of 12 key materials that could be produced from sugars and that could be used to make high-value products such as bioplastics. In addition to providing a sustainable source of succinic acid, the new technology could have numerous environmental benefits, Lin explained.

Currently, Starbucks Hong Kong's food waste is incinerated, composted or disposed of in landfills. Lin says her biorefinery process could convert these piles of foul-smelling waste into useful products, getting trash off the land without incineration and putting fewer pollutants into the atmosphere.

The biorefining process uses the greenhouse gas carbon dioxide, keeping it from forming part of the heat-trapping blanket that is raising the planetary temperature.

Because succinic acid and its products, such as bioplastics, are made using bakery waste as a renewable feedstock, they are sustainable alternatives to conventional plastics that are made with petroleum.

The biorefinery process could help recover some of the 1.3 billion tons of food trashed, dumped in landfills and otherwise wasted around the world every year.

Dr. Lin said that the process could become commercially viable on a much larger scale with additional funding from investors.

"In the meantime, our next step is to use funding we have from the Innovation and Technology Commission from the Government of the Hong Kong Special Administrative Region to scale up the process," she said. "Also, other funding has been applied to test this idea in a pilot-scale plant in Germany."

To help start the research, Starbucks Hong Kong donated part of the proceeds from each purchase of its "Care for Our Planet Cookies" gift set. In addition, the project has received a grant from the City University of Hong Kong.

Copyright Environment News Service (ENS) 2012. All rights reserved.

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