Korean researchers find one-step route to PLA

Up until now PLA has been produced using a two-step process of fermentation and chemical polymerisation, which the researchers say is both complex and expensive.

Through the use of a metabolically-engineered strain of E coli, the research team has been able to develop a single-stage process that produces PLA and its copolymers through direct fermentation.

The scientists claim their new production process, which is published in two papers in the latest edition of the Biotechnology and Bioengineering journal, could make renewable production of PLA and lactate-containing copolymers cheaper and more commercially viable.

While PLA is one of the less costly bioplastics available today, it still carries a price premium over many of the traditional petroleum-based resins it could replace.

“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 team leader Professor Sang Yup Lee.

“This new strategy should be generally useful for developing other engineered organisms capable of producing various unnatural polymers by direct fermentation from renewable resources”.

The South Korean research illustrates the efforts being made by researchers to use genetic modification – currently highly unpopular with the European public - to improve the cost and efficiency of production techniques based on renewable feedstocks.

Last month Metabolix announced the latest results from its work to manufacture PHA (polyhydroxyalkanoate) polymers in genetically-modified tobacco crops.

Sustainability issues will be on the agenda at a special one-day conference - Sustainable Plastics Packaging - organised by European Plastics News in Brussels, Belgium, next week. Click here for more details.