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An increasing number of corporations have begun producing biodegradable plastics and other materials less harmful to the environment, reflecting rising environmental consciousness.

Unlike conventional petroleum-based plastic, biodegradable plastic is broken down by microorganisms when placed in the ground.

According to the Biodegradable Plastics Society, a Tokyo-based body made up of more than 200 private companies, it costs 300 yen to 350 yen to produce 1 kg of plastic from plants, three to four times as much as it costs to produce the same amount of petroleum-based plastic.

But demand for biodegradable plastic is rising, an official of the business body said.

In 2000, production of the environmentally friendly plastics stood at slightly more than 2,000 tons.

“It is expected to increase to 50,000 tons this year and to 200,000 tons in 2010,” the official said.

Ajinomoto Co. has been producing plant-based polybutylene succinate (PBS), using its fermentation process.

The company ferments sugar and starch, and extracts succinic acid from them. The acid is then combined with 1.4-butanediol to produce PBS, a highly flexible plastic. The 1.4-butanediol comes from Mitsubishi Chemical Corp.

“Since the raw materials are plants, the plastic can be broken down after use by microorganisms in soil,” an Ajinomoto official said.

The price of the plastic is still relatively high, at several yen per shopping bag. But the official is confident the price will fall due to planned mass production.

The use of the easy-to-grow fibrous plant kenaf is growing.

Matsushita Electric Works, a home appliance and electronics equipment maker, began producing 100,000 kenaf-fiber boards a month in a joint venture with a Malaysian firm in December.

Kenaf matures in four to five months and yields about 200,000 tons per hectare, five to 10 times more than Japanese cedar trees.

A 4-mm thick kenaf fiber board is said to have more tensile strength than a 9-mm thick piece of conventional plywood. Research is being done to further enhance the strength by mixing kenaf fiber with plant-based plastic.

Toyota Motor Corp. uses floor mats made of kenaf fiber in some of its cars.

Japan’s leading carmaker has also begun producing polylactic acid (PLA), a type of biodegradable plastic made from the starch and sugar extracted from such plants as sweet potatoes.

Domestic annual demand for plastics stands at about 14 million tons.

“Biodegradable plastics will account for about 10 percent of the market in around 2020,” the official of the Biodegradable Plastics Society said.

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