April 24, 2007 4:00 AM PDT

Plastic goods for your compost heap

CAMBRIDGE, Mass.--Biotech firm Metabolix and agriculture giant Archer Daniels Midland plan to sell a plastic that could benefit everyone from backyard composters to marine animals.

At a press conference here Monday, Metabolix announced the brand name--Mirel--for its biodegradable plastic made from corn and said it will be used in several consumer products including razor holders and gift cards.

The plastic pellets will be produced through a joint venture called Telles between Cambridge, Mass.-based Metabolix and ADM, which expects to have a corn-processing plant in Clinton, Iowa, operating in the second half of 2008.

The idea behind Mirel is to brand products or their packaging as a greener alternative to conventional plastics, which are made from petroleum, said Metabolix CEO James Barber. Like a growing number of "green," or so-called clean tech, companies, Metabolix is appealing to consumers' growing concerns over the environment and sustainability.

Companies can use the Mirel logo to indicate that it's an Earth-friendly plastic that can decompose within a few months, depending on the circumstance.

By contrast, things like plastic bags--part of the 350 million pounds of plastic created every year--remain in the environment "virtually forever," Barber said. The petroleum to make these plastics accounts for 10 percent of the oil the U.S. consumes, he said.

Metabolix expects that consumer-goods packagers will charge slightly more because they are "premium" goods. A coffee sold in Mirel packaging, for example, would cost consumers a few cents more, Barber said.

Metabolix is in talks with 40 prospective customers for 60 different applications including coffee cups and lids and plastic bags, he said.

Plastic microbes
American Excelsior has already developed a line of plastic stakes to hold down its erosion prevention blankets. The plastic stakes are better than metal stakes because they will not rust in seawater and don't require crews to retrieve them at the end of their use, said Jerry Bohannon, director of earth science at American Excelsior.

The company will also upgrade its software so that engineers can design systems around biodegradable products, a move that will allow "engineers to create products with the environment in mind," Bohannon said.


Mirel will initially be made from corn starch, but other sources of sugar can be used as well.

Meanwhile, Metabolix is already at work on a second generation of plastics grown within plants.

The company is developing a method by which the microbes that make up its biodegradeable plastic can be produced within switchgrass, Barber said.

The microbes, which are innocuous to the switchgrass they're growing in, can be extracted and made into plastic pellets. Residual biomass also could be converted into biofuels. "It'll be huge," he said, adding that the process will be available in about five years.

Mirel plastic stems from genetic research started at the Massachusetts Institute of Technology nearly 20 years ago.

The plastic is made by combining genes of several naturally occurring substances and making them function together, said Oliver Peoples, chief scientific officer and co-founder of Metabolix.

Genetic engineering is well understood but hasn't been widely applied to plastics, he said. Mirel uses many of the same techniques that pharmaceutical companies do.

"We are interested in using a number of genes to assemble teams of genes and make them work in living cells," Peoples said.

CONTINUED: Paper, plastic or bio-plastic?…
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Is It Really Better?
OK, so traditional plastic is made from petroleum and it doesn't degrade (or do so very slowly). Traditional plastic can be recycled.

The questions I have are:

1. Is there any side effect on the environment from the modified corn starch when it degrades? Just because they call it "green" and make it from plant materials doesn't make it good for the environment. After all, petroleum comes from plants, too.

2. What is the total cost? There's energy expended to retrieve and refine petroleum, and energy is needed to produce and recycle traditional plastics. Likewise, there are effects from growing, harvesting, and refining corn plus those of creating Mirel. On balance, which is better?

3. How practical is Mirel? For example, under what conditions does Mirel degrade? Will a water spill cause a leak? What if it's left outside? How long before the container is useless? Can Mirel be used only for dry goods? If it's used for frozen foods, will melting ice/frost be a problem? Can it be used for medical supplies?

I'm sure there are other questions, but these are the sorts of things I'd like c|net to share with us. Most of these green stories simply convey ideal notions rather than asking tough questions and comparing the whole picture. I'd like to see more in the future.
Posted by c|net Reader (856 comments )
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"(or do so very slowly)" should have been "(or does so very slowly)" of course.
Posted by c|net Reader (856 comments )
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Some answers from reporter
1. As I understand this, it's made from plain old corn starch so there won't be any unknown environmental effects as products degrade.

2. I don't have a detailed analysis of the two separate processes of making plastics from oil and plastics from petroleum, but on balance, it appears that plant-based plastics take less energy over its lifecycle. Just looking at disposal, a plant plastic will degrade with no effort (and creates fertilizer), whereas recycling takes additional energy. And, as you point out, extracting and refining oil and creating plastics is very energy-intensive.

There are other potential benefits as well, when you consider that a lot of plastic is not recycled and simply remains an environmental pollutant for a long time.

3. Mirel can be used for liquid containers, even boiling water and won't degrade. The process takes months, depending on thickness, but decomposition will only happen if the plastic is buried in soil or in bodies of water where microbes can eat away at it.

Finally, I think you raise a good point about our green tech coverage overall. Many products aim to be environmentally friendly but nearly everything will have some sort of drawback or limitation. We can try to lay out the pros and cons and introduce more analysis.
Posted by mlamonica (330 comments )
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