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Turning food waste into plastic

By Kiesha Porter

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(CNN) -- A meal you don't eat could return to your kitchen table not as leftovers, but as plastic wrap.

Using food scraps, biochemical engineer Jian Yu and colleagues at the Hawaii Natural Energy Institute in Honolulu have come up with what they claim is an inexpensive way to make a biodegradable polymer.

The substance could be used in disposable products such as bottles, wrappers and even surgical instruments, according to the researchers, who recently published their work in the journal Environmental Science and Technology.

Plastics engineers with the British company ICI began making this type of polymer about a decade ago, but they used pure sugar and organic acid, a much more costly process.

Food waste can reduce the expense by 40 percent, according to the Hawaii researchers. It contains more organic matter that can be easily digested by microbes for polymer biosynthesis, they said.

Besides cost savings, the new method is more environmentally friendly than conventional plastic manufacturing, Yu said.

"We discharge millions of tons of organic wastes from food production and consumption. Dumping them in landfill sites causes many environmental problems, such as odor, greenhouse gas (methane) and attraction to insects."

A grimy, slurry mix

Yu and his team collected food scraps from a restaurant and blended them with water to create a grimy, slurry mix. The concoction was stored in a warm, airtight container for a few weeks so that strains of bacteria that survive without oxygen would multiply.

The anaerobic bacteria break down the organic molecules in the food. The process releases acid that filters through a silicone rubber sheath, where other bacteria convert it into a biodegradable polymer.

"In my opinion, most of our packaging and disposable should be biodegradable," Yu said. "The bioplastics are good candidates ... for various short life disposable applications in our daily life because they can be eaten by microbes in the environment."

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