Washington: Scientists have successfully bio-engineered polymers, completely bypassing fossil fuel based chemicals.

This breakthrough opens the way for the commercial production of 'green' plastics. Polymers are molecules found in the form of plastics and rubbers.

The team, from KAIST University, South Korea and LG Chem, led by Sang Yup Lee, professor, focused on polylactic acid (PLA), a bio-based polymer, the key to producing plastics through renewable resources.

"The polyesters and other polymers we use every day are mostly derived from fossil oils made through the refinery or chemical process," said Lee.

"PLA is considered a good alternative to petroleum based plastics as it is both biodegradable and has a low toxicity to humans," he added.

Until now PLA has been produced in a two-step fermentation and polymerisation, which is both complex and expensive.

Now, through the use of a metabolically engineered strain of E. coli, the team has produced polylactic acid and its co-polymers through direct fermentation.

This makes the renewable production of PLA and lactate-containing copolymers cheaper and more commercially viable, said a KAIST University release.

"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 Lee.

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

These findings were published in Biotechnology and Bioengineering. IANS