環境・バイオ・プラスチックリサーチ

2021年06月12日

藻類バイオマス国際会議（ISAP2021）の藻類バイオプラスチックセッションで、セルロース系と藻類由来のパラミロン系のバイオプラスチックの開発について講演しました。（2021.6.10、オンライン開催）

<概要＞

Development of highly functional bioplastics using cellulose and their application to algae based-bioplastics

Masatoshi Iji^1､2, Midori Yamashiro³, Shukichi Tanaka³, Makoto M. Watanabe²

1 Eco-Bio Plastics Research, Tokyo 183-0011, Japan

2 ABES, University of Tsukuba, ABES, Ibaraki 305-8572, Japan,

3 System Platform Research Laboratories, NEC Corporation, Chiba 270-1198, Japan

Biomass-based plastics (bioplastics), as an alternative to petroleum-based plastics, have distinct advantages in ability to fix CO₂ gas that causes global warming and prevent exhausting petroleum resource, On the other hand, currently mass-produced bioplastics are using starch as the main resource, produced from plants that are generally edible.

We developed highly functional bioplastics using polysaccharides, which is the largest amount of biomass produced on the earth, especially cellulose as a stable non-food plant resource. Furthermore, we have developed new bioplastics using microalgae biomass as a polysaccharide to greatly reduce CO₂ emitting amount based on the cellulose-based bioplastics.

The cellulose-based bioplastics are mainly consisting of cellulose, a long side chain component such as cardanol derived from cashew nut shell and stearic acid, and a short side chain component such as acetic acid and propionic acid^1-3). The bioplastics achieved high durable properties and thermoplasticity, which are sufficient for the use in many durable products. The bioplastics were produced by a new semi-heterogeneous synthesis process, in which the solvent usage was greatly reduced. As a result, the CO₂ emitting amount in the production is about half, comparing with current highly functional petroleum-based plastics such as PET. Also, we developed a highly decorative technology realizing “Urushi black” of Japanese traditional lacquer wares by compounding with specific black elements and a screen printing technology reappearing a top level minute brushwork of “Makie” to expand the usage of the cellulose-based bioplastics in high-end various products³⁾

Algae biomass is greatly expected as coming non-food resource of bioplastics because of its various and useful chemical structures for bioplastic’s production. In particular, long chain fatty acids and paramylon (β-1,3glucan) as a polysaccharide produced by specific algae (Euglena, Monoraphidium) are valuable components. Based on the above-mentioned cellulose-based bioplastics, we have developed algae-based bioplastics using these components to further reduce CO₂ emitting amount in the production comparing with the cellulose-based bioplastics by the cultivation of the algae using CO₂-rich gas from cement factory for microalgal carbon source and sewage water for microalgal nitrogen and phosphorus resources. We verified the bioplastics’ good durability (strength, heat resistance) compared to the cellulose-based bioplastics and greatly lower CO₂ emitting amount (about zero) in the production. We are aiming to expand the algae-based bioplastics for the use in various durable products following the cellulose-based bioplastics