KAIST/LG Chem Improve Bio-Plastics Process

New process cuts cost and complexity for biodegradable plastics.
By Levi Beckerson, DailyTech, Nov. 23, 2009

Polylactic Acid doesn’t sound like a friendly neighborhood chap, but it is in fact a common plastic. Not only is it biodegradable, it can be made from renewable resources like sugarcane and corn starch. The current common technique for producing PLA is both expensive and complex, involving bacterial fermentation and then chemical polymerization.

A collaboration between KAIST University (Korea) and LG Chem, led by professor Sang Yup Lee, has developed a new process which produces PLA using the same resources. The process is a one-step direct fermentation, but it utilizes a slightly unsavory, though common bacterial component: E. coli.

“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. This means that a developed E. coli strain is now capable of efficiently producing unnatural polymers, through a one-step fermentation process,” explains Lee.

“The polyesters and other polymers we use everyday are mostly derived from fossil oils made through the refinery or chemical process. 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.”

Though the use of E. coli in the process seems at first unsettling, the benefits of such a process are readily apparent. Reduced production cost would allow for greater use of PLA in plastic products, possible reducing or even replacing the need for many of the non-biodegradable, petroleum-based products presently in use. Though it may indeed be a small step, Lee’s team’s research adds another bio-friendly product to a stack of growing “greener” products and resources.

The research work is published in the 50th anniversary of the journal Biotechnology and Bioengineering.