RIKEN Improves Photosynthesis Bioplastic Production to World's Highest Level

A microscope image of a genetically modified cyanobacterium.
Red dye indicates the likely accumulations of PHA.
Photo courtesy of RIKEN / Photo by Ng Kiaw Kiaw

RIKEN, Japan's comprehensive science research institution, announced on January 23, 2014 that its joint research with Universiti Sains Malaysia using genetically modified cyanobacteria yielded the most efficient bioplastic production by photosynthesis in the world.

Although bioplastic has begun gaining broader usage with its significantly lower environmental burden when compared to its petrochemical counterpart, production costs have been a drawback for one such bioplastic, polyhydroxyalkanoate (PHA). It is typically produced by bacterial fermentation, which requires bacterial cultivation equipment and large amount of sugar as carbon source for the bacteria.

The joint research team focused on photosynthetic cyanobacteria that exclusively use atmospheric carbon dioxide to grow. They introduced genes from bacteria that contribute to the synthesis of bioplastic into these cyanobacteria, and cultivated them in mineral salt medium to induce photosynthesis using atmospheric carbon dioxide. The genetically modified cyanobacteria produced PHA at 14 percent of their dry weight, which is the highest reported level of PHA production by photosynthesis alone. When 0.4% acetic acid was added, the production was successfully raised to 41%.

These results are hoped to advance photosynthetic bioplastic production as a greener, safer and more economical process.