Simpler, cheaper, biodegradable plastic without using fossil fuels


November 22, 2009

Biodegradable cups made from corn at Chubby's Tacos in Durham, North Carolina (Photo: Ildar Sagdejev (Specious) via Wikipedia Commons)

Biodegradable cups made from corn at Chubby's Tacos in Durham, North Carolina (Photo: Ildar Sagdejev (Specious) via Wikipedia Commons)

In recent years, polylactic acid (PLA) has attracted attention as a replacement for petroleum-based plastics. It is made from corn-starch, or other starch-rich substances like maize, sugar or wheat, and is biodegradable – reverting in less than 60 days in ideal conditions. PLA is already used as a material for compost bags, food packaging, and disposable tableware, and also for a number of biomedical applications, such as sutures, stents, dialysis media and drug delivery devices. Although its price has been falling, PLA is still more expensive than most petroleum-derived commodity plastics, but now a team of researchers has succeeded in simplifying the production of PLA and making the process much cheaper, meaning we could soon see PLA used in a much wider variety of applications.

Until now PLA has been produced in a two-step fermentation and chemical process of polymerization, which is complex and expensive. Now, through the use of a metabolically-engineered strain of E.coli, the team from South Korea’s KAIST University and the chemical company LG Chem, have developed a one-stage process which produces polylactic acid and its copolymers through direct fermentation. This makes the renewable production of PLA and lactate-containing copolymers cheaper and more commercially viable.

"By developing a strategy which combines metabolic engineering and enzyme engineering, we've developed an efficient bio-based one-step production process for PLA and its copolymers," said the research team’s leader, Prof Sang Yup Lee. "This means that a developed E.coli strain is now capable of efficiently producing unnatural polymers, through a one-step fermentation process."

This combined approach of systems-level metabolic engineering and enzyme engineering now allows for the production of polymer and polyester-based products through direct microbial fermentation of renewable resources.

"The polyesters and other polymers we use everyday are mostly derived from fossil oils made through the refinery or chemical process," said Lee. "The idea of producing polymers from renewable biomass has attracted much attention due to the increasing concerns of environmental problems and the limited nature of fossil resources. PLA is considered a good alternative to petroleum-based plastics as it is both biodegradable and has a low toxicity to humans."

The team's research is published in two papers in the journal Biotechnology and Bioengineering.

About the Author
Darren Quick Darren's love of technology started in primary school with a Nintendo Game & Watch Donkey Kong (still functioning) and a Commodore VIC 20 computer (not still functioning). In high school he upgraded to a 286 PC, and he's been following Moore's law ever since. This love of technology continued through a number of university courses and crappy jobs until 2008, when his interests found a home at Gizmag. All articles by Darren Quick

\'Bout time. I would pay an extra nickel a cup for something I knew wouldn\'t end up lasting for a thousand years, whether in a landfill, or in the gutter or river...

Also nice to reduce our oil dependence as a side benefit.

Kudos to the research team!



Why don\'t plastic companies just go out to the Great Pacific Garbage Patch and get all the plastic they need? Put a modified oil rig in the center as the processing plant and you could load any number of cargo ships.

Plus the plastic has been discarded once, so you know it\'s not wanted. Basically the plastic company would just pay for separation and transportation.

Matt Bear

Made from corn huh? Better not from the parts of corn that people would like to eat. There are too few crops on this globe to feed everyone, especially the hungry obese West. Just like biofuels, it seems like a good plan, but is it?

Jan Klok

Would like to have further confirmation, PLA is categorized in compostable or biodegradable plastic? It is quite confusion since some media state that it is compostable but not biodegradable plastic.....

Tiong Patrick

I love to read about this type of technology advancement, I really believe that ecologically friendly products and energy sources is what will make America great again! I currently have a few vertical axis wind turbine s on my property and they work wonders! I plan on incorporating solar at some point but im waiting for the technology to make it worth it. thanks again for the great article!

Rockett Singh
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