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Over The Horizon

Biodegradable Plastic from Bugs

There is considerable demand for short-life plastics that readily biodegrade, and Industrial Research has been developing bioplastics for a large US firm. The team was contracted by Monsanto subsidiary NutraSweet Kelco to produce four different types of bioplastics on a pilot scale. These were needed for Monsanto's thermoplastic engineering studies in a bid to develop new types of biodegradable plastics.

Many micro-organisms produce plastics within themselves which are biodegradable; between 50-60% of a micro-organism's body weight can be bioplastic. IRL's Julian Davies says that researchers have known about bioplastics for over 50 years.

"It's really the high cost of making bioplastics which has been the prohibitor to making them. Conventional plastics cost about $1 per kilogram, compared with bioplastics which cost around $10 per kilogram to make."

Bioplastics can be processed on the same equipment used for making conventional plastics, including injection moulding and extrusion blow moulding.

Currently, Monsanto is the only company worldwide which makes bioplastics commercially, producing Biopol which is used in high-value applications such as medical containers. Their aim is to make a bioplastic with a different structure and properties, which can be moulded in different ways. Ongoing work includes finding more uses for the material in its current brittle form, as well as attempting to reduce this brittleness.

There are plans afoot for Industrial Research to produce 100 kilograms of bioplastic for testing at Monsanto in the future, according to Chris Guske, fermentation technology leader for NutraSweet Kelco. As well as the conventional applications for bioplastics such as plastic bags and bottles, Guske cites other uses such as golf tees, disposable razors, credit cards and wound dressings.