A Japanese research group announced that it has developed a micro seaweed bioplastic by using a material extracted from Euglena cells as a main raw material.

The group consists of Motonari Shibakami (a senior researcher at the Biomedical Research Institute of Japan's National Institute of Advanced Industrial Science and Technology (AIST)), Masatoshi Iji (the chief researcher at the Smart Energy Research Laboratories of NEC Corp) and Masahiro Hayashi (an associate professor at the Faculty of Agriculture, the University of Miyazaki). The research has been conducted as part of the Advanced Low Carbon Technology Research and Development Program of Japan Science and Technology Agency (JST).

The plastic is synthesized by adding a grease extracted from Euglena or cashew nut shell to a polysaccharide in which a large number of Euglena cells are raised (paramylum). The added grease is (1) a long-chain fatty acid synthesized by using "wax ester," which is a grease that is produced when paramylum is decomposed inside Euglena cells, or (2) cardanol, which is a grease contained in cashew nut shell and has flexible, long chain-like parts and rigid hexagonal parts.

The synthesized plastic has high thermal plasticity and heat resistance. And its plant component ratio is as high as about 70%.

In general, micro seaweeds that photosynthesize under water have a higher solar energy use efficiency than land plants. Especially, Euglena can directly use highly-concentrated carbon dioxide (CO2), enabling to use light with a high efficiency. Also, it can be cultured in a safe waste water from, for example, a food factory, potentially reducing the amount of energy consumed for producing plastic.

The polysaccharide used as a main raw material is (1,3) β-glucan, which is a natural polymer consisting of many connected glucoses. Cellulose ((1,4) β-glucan), which constitutes wood, etc, is also a polymer consisting of many connected glucoses.

However, the glucoses of Cellulose and those of the polysaccharide are connected in different ways. As a result, cellulose has a sheet-like structure while (1,3) β-glucan has a one- or three-layer spiral structure.

When the research group measured the physical properties of the plastic, it found that the impact strength, etc of the plastic needed to be improved but its heat plasticity is equivalent to those of other bioplastics (such as polylactic acid and Nylon 11), cellulose acetates containing a plasticizer and petroleum-based ABS (acrylonitrile butadiene styrene) resins. And the heat resistance of the new plastic is higher than those of such plastics, the group said.

There are no major differences between the plastic made with the long-chain fatty acid synthesized by using the wax ester and the plastic made with cardanol.