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Re: [greenyes] Plastic from corn?

Matthew, a cynic might say the point of bio-based plastics is to make big bucks for the big corporations who manufacture them, not to compost! Also, as markets for tradable renewable/greenhouse gas reduction credits evolve worldwide, there's probably discussion that companies substituting bio sources for non-renewable sources for plastic manufacture will own the credits that accrue from that bioplastic, adding to its value.

Once again, we do have a manufacturer not really too concerned about end-of-life issues for the products, I note. Without stronger producer responsibilty laws, stuff like PLA plastics will be a headache for recyclers & composters and not for the companies who profit from them....

USCC has a session on biobased plastics at its upcoming conference early next year. Anyone on this list who attends - if you can, please report out on the discussion there!

Can't remember if these factoids have been mentioned on this thread; here are some interesting dimensions to this issue:
-- <5% of GMO (genetically modified organisms) corn goes to PLA made by C-D right now. However, use of GMO for bioplastics and biomass-to-energy generation is one use some think may be acceptable (as opposed to food uses of GMO seeds). However, cross-contamination of crops from GMO to non-GMO is a concern. Apparently 70% of the soy in the US is GMO and no one can certify (except probably organically grown) that soy in food products isn't GMO.
-- I believe only about 7% of the world's petroleum goes to plastics right now, so replacement of petro-derived plastics with bio-derived plastics isn't going to get us off non-renewable sources right away - tho every step helps on that front.

Anne Peters
Gracestone, Inc.
Boulder, CO
303.494.4934 vox
303.494.4880 fax

Matthew Cotton wrote:

Being a composter, maybe I'm missing something in this discussion, but isn't the point of corn/soy based plastics that you can compost them? So rather than look at them as a contaminant in plastics recycling (which is obviously a concern), why not look at them as an exciting new way to remove that much more material from the waste stream into a cycle which makes them into compost which can be used to grow corn, soybeans, wine grapes, etc.?

Pat is right though about the issue of separating the two "plastics" in the recycling stream. How will the public (or the operators, or the sorters) learn that some "plastic" is biodegradable and some is not? I'm not sure it makes sense to use biodegradable plates, cutlery, packaging, etc. if its just going to end up in a landfill.

As for groups to tap into, the US Composting Council discusses this issue regularly and many members have far more knowledge about and experience with biodegradables than I. Check out:

Matthew Cotton
Integrated Waste Management Consulting
19375 Lake City Road
Nevada City, CA 95959
(530) 265-4560
Fax (530) 265-4547

Join us at the US Composting Council's 13th Annual Conference and Trade Show, January 23-26, 2005 at the Crowne Plaza Riverwalk in San Antonio, TX
Register at

On Nov 30, 2004, at 6:10 AM, Pat Franklin wrote:

Don makes a good argument for corn/soy-based plastics over petroleum-derived
plastics, but I don't think it's quite that simple particularly when you get
into the area of recycling and how the two types of plastics interact in the
recycling stream. This is an interesting and important dialogue that (in my
mind) needs to continue. Does anyone know what group(s) we might tap into
for more information?

Pat Franklin

-----Original Message-----
From: D Hughes [mailto:djhughes@no.address]
Sent: Monday, November 29, 2004 10:26 PM
To: Jenny Gitlitz; greenyes
Cc: Maine, Bruce
Subject: Re: [greenyes] Plastic from corn?

There are two major advantages that corn- or soy-based plastics have over
their petroleum-derived counterparts. First, they are renewable. Second,
they are biodegradable. The consequences of these two advantages, taken
together, are immense: growing corn does not contribute to global warming,
to anywhere near the extent that petroleum does; nor does it create a waste
product which, unless incinerated, lasts virtually forever. Plastic litter
is the most commonly seen pollutant in the world's oceans, and has led to
the death of untold numbers of marine wildlife. That in itself should be
reason to make the switch.
Don Hughes

ps. Cutting back on pork and beef consumption would not be a bad idea,
both in terms of better health and reducing human impacts on the

t 08:48 AM 11/29/2004, Jenny Gitlitz wrote:

On 11/29/04 8:12 AM, Maine, Bruce at Bruce.Maine@no.address wrote:

Sacrificing food resources for consumer goods doesn't seem
to make a lot of sense

From what I understand, "sacrificing" food resources is not an issue.


is a surplus of corn grown in the U.S.--subsidization accounting for the
glut. Also--the vast majority of corn grown in the U.S. is used as cattle
feed, not as a direct food source for humans. If we were all to become
vegetarians or vegans, we could probably cut the land (and water & energy)
used to grow our agricultural products by 80-90% (not to mention ag


From what I understand, the energy inputs used to grow and process

corn-based plastics may exceed the energy value of comparable plastic resin
from petroleum. I have not seen a complete life-cycle analysis on this, so


can't vouch for this. I am curious to learn if this can be done with net
energy savings over traditional plastics manufacture.

Other factors must be kept in mind, too: pesticide use, for one. American
corn manufacture is a monocrop process that is pesticide-, fertilizer-, and
water-intensive, and reduces the potential (=historical) biodiversity of


plains. Trading one monocrop output (beef) for another (corn plastics)
doesn't seem like a big win for our society. If the corn could be grown
organically, intercropped with other grains, and bred to be
drought-tolerant, the overall picture might be different.


Jennifer Gitlitz
Research Director, Container Recycling Institute

Home Office:
2 Pomeroy Ave.
Dalton, MA 01226
Tel. (413) 684-4746
Mobile: (413) 822-0115
Fax: (413) 403-0233
Email: jgitlitz@no.address

Please note the new address for CRI¹s main office:
Container Recycling Institute
1601 North Kent St., Suite 803
Arlington, VA 22209-2105
Tel. (703) 276-9800
Fax: (703) 276-9587

Don Hughes, PhD student *
Dept of Chemistry, 431 Jahn Laboratory *
SUNY-College of Environmental Science & Forestry
Syracuse, NY 13210 *
315-470-6597 djhughes@no.address *
"When I was younger I could remember anything,
whether it happened or not."
Mark Twain (1835-1910); US writer and journalist.

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