Plastic plant-astic!

Car giant looks to sweet potatoes for a bioplastic future

The white coats at Toyota see the sweet potato as an all round good egg. On top of its great potential as a source of hydrogen for fuel cells, and a nutritious alternative to corn in livestock feed, it’s now set to become a big hitter in bioplastics. The sweet potato’s biggest fan is Kozaburo Tsukishima, general manager of the company’s biotechnology and afforestation division.

In a simile which admittedly loses a little of its resonance if you know zilch about Japanese baseball, he recently described the knobbly orange vegetable as “a secret weapon with the potential to become as great a home run batter as Hideki Matsui”. In recent years Toyota has been adapting the structure of its business to respond to the challenges of the ‘recycle-oriented society’, as foreseen in its medium-term business plan Global Vision 2010. Accordingly, the world’s second largest motor vehicle manufacturer has set up several non-automotive divisions in recent years, including Tsukishima’s (in 1998).

And the development of biodegradable plastics - which are both recyclable and carbon neutral - is one area of biotech in which it aims to become a major player. Today’s output may be only a measly 20,000 tons, but Toyota has set itself an ambitious 2020 target of 20 million tons, worth a cool 5,000 billion yen. The early interest from companies such as Fujitsu and cosmetics manufacturer Shiseido suggests that target might be achievable.

And it’s as a source of carbon neutral and biodegradable plastic that sweet potatoes are really cookin’ on gas. Enzymes break down the sweet potato starch into sugar, which is then fermented to produce lactic acid. This is polymerised into polylactic acid and refined and moulded into its final shape.

Although Toyota Eco-Plastic has made only a tentative appearance to date - in the floor mats of the new multi-purpose Raum, a vehicle only available in Japan - Tsukishima sees exciting scope for development and progress. “If we continue, 10 years down the road Toyota will produce a Nobel Prize winner in this field,” he predicts. - Esther Maughan

Toyota Global Environmental Report 2003
www.toyota.co.uk/bv/aboutus/E_kankyouohoukoku2003.pdf

12 July 2004

Esther Maughan McLachlan