Bioplastic bottles

Made from renewable biomass sources such as vegetable fats and oils or corn starch, bioplastics have long been seen as being the plastic of the future.

Coca-Cola, the world's largest beverage company, hopes someday to sell its products in bottles made fully from plants, like corn and sugarcane. The US soft-drink giant already uses bottles made partially of renewable biomass resources. Since 2009, in fact, more than 15 billion such bottles have left its global facilities, the company says.

Whether it's Coca-Cola, Pepsi or Nestlé, nearly all major bottlers are showing a marked interest in bioplastics. Economic reasons are perhaps the biggest motivator for companies in the fiercely competitive soft-drink industry.

Most plastic bottles today are still made from fossil fuel resources, like petroleum. But oil, experts agree, isn't going to get any cheaper in the coming years as global reserves dwindle. Many beverage companies are now taking the view that bioplastics, derived from renewable resources, are a more sustainable alternative, from a cost and supply point of view.

Changing direction

Then there's the environmental factor. On the one hand, beverage producers want to show environmentally-conscious consumers that they're serious about reducing their carbon footprint. That's good for their image and good for sales.

On the other hand, they don't have much choice. Governments around the world, especially in industrialized nations, are approving rules and regulations to force manufacturers to reduce their carbon dioxide emissions.

"There is clearly momentum in the bioplastics market," says Kristy-Barbara Lange from the European Bioplastics Industry association in Berlin. "But there's also plenty of confusion about what bioplastics actually are. We need to harmonize standards and labels. And consumers also need to have a better understanding."

One of the most widely-used bottling materials today is polyethylene terephthalate, better known as PET. According to industry experts, the plastic material is ideal for soft drinks with carbonation, which requires durability. It's also colorless, which is important for selling many drinks. But, it normally has a high petroleum content.

'Green polyethylene'

Efforts are underway to change that. Coca-Cola, for instance, has developed a bottle made with a PET resin that contains bio-based monoethylene glycol (MEG). Currently, the bottle consists of up to 30 percent MEG and 70 percent purified terephthalic acid (PTA). The company is working on technology to develop PTA from plants but claims it's complicated science and doesn't expect a commercial breakthrough for a few more years.

The Brazilian company Braskem has developed an alternative bioplastic product it calls "green polyethylene" or Green PE. The product, obtained from sugarcane ethanol, has many performance features of traditional fossil fuel-based polyethylene but not all of them.

"It is highly recyclable, up to 10 times, and can be used in light-weight bottles," said Marco Jansen, European commercial director for renewable chemicals at Braskem. "But, unlike PET, it is translucent."

Biodegradability an issue

Both bio-based PET and Green PE bottles are generally not biodegradable. Supporters of these products say that's a good thing.

Suppliers and users of non-biodegradable bioplastics are focused on high recyclability, according to Jansen. “There is far more value in reusing materials,” he told DW. "It's more sustainable from a carbon footprint perspective and it's more economic."

Professor Hans-Josef Endres, from the Institute for Bioplastics and Bio Composite Materials at the Hanover University of Applied Science and Arts, fully agrees. "There are two bioplastic camps. Those in favor of recyclable materials and those who prefer biodegradable materials and that’s a bit of a dilemma," he told DW.

The Austrian company, Naku, sees a market for biodegradable bottles though. The company has developed a bottle based on polylactic acid, a plastic substitute made from fermented plant starch that comes from plants rich in carbohydrates like corn and potatoes. Naku’s water bottles need between 35 and 90 days to biodegrade, compared to 350 years for a traditional plastic bottle, according to company founder Johann Zimmermann.

But there are still challenges for these new products. The bottle is about 20 euro cents more expensive than a petroleum-based plastic bottle. Another is its durability, which Zimmermann claims is about six to eight months compared to about a year for conventional bottles.

While bioplastics, whether biodegradable or not, are generally viewed as good for the environment, there is some concern about using food stocks to make them, especially corn and sugarcane crops.

"Work is underway to develop second-generation renewable resources, which could include other plants and even waste products," Lange from the European Bioplastics association told DW. "There will be alternatives in the future."