Creation of new biodegradability controlled plastics based on the degradation mechanism

• Project/Area Number: 17K00619
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Environmental conscious materials and recycle
• Research Institution: Hokkaido University
• Principal Investigator: Ooi Toshihiko 北海道大学, 工学研究院, 准教授 (40223713)
• Co-Investigator(Kenkyū-buntansha): 田口 精一 東京農業大学, 生命科学部, 教授 (70216828) ; 松本 謙一郎 北海道大学, 工学研究院, 教授 (80360642) ; 堀 千明 北海道大学, 工学研究院, 助教 (50722948)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Project Status: Completed (Fiscal Year 2019)
• Budget Amount: ¥4,810,000 (Direct Cost: ¥3,700,000、Indirect Cost: ¥1,110,000); Fiscal Year 2019: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000); Fiscal Year 2018: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000); Fiscal Year 2017: ¥2,080,000 (Direct Cost: ¥1,600,000、Indirect Cost: ¥480,000)
• Keywords: 生分解プラスチック / PHA / 環境分解 / 乳酸ベースポリマー / 微生物合成 / 乳酸コポリマー / デポリメラーゼ / 環境微生物 / 生分解性プラスチック / 環境分解性制御 / バイオプラスチック / 生分解性 / 環境浄化 / ポリ乳酸 / 分解制御

Outline of Final Research Achievements

Marine pollution caused by petroleum-derived plastics has become a global concern. Among them, biodegradable plastics that can be decomposed in the natural environment into water and carbon dioxide are attracting attention. In this research project, we developed a newly developed bioplastic, lactic acid copolymer [P (LA-co-3HB)], which is a polymer molecule composed of lactic acid (LA) and 3-hydroxybutanoic acid (3-HB). And the degradability by environmental microorganisms was evaluated.
First, we investigated the microbial production method of lactic acid copolymer and established a culture method with controlled lactic acid content. The obtained copolymer were formed into a film to evaluate the degradation in the environment, and a phylogenetic analysis of the environmental microorganisms involved in the degradation was performed.

Academic Significance and Societal Importance of the Research Achievements

乳酸分率を制御した乳酸コポリマーの微生物生産法を確立した。
乳酸分率の異なる乳酸コポリマーの環境分解性について評価した。土壌中では乳酸分率の上昇に伴い分解速度は遅くなった。土壌から単離した分解微生物の系統解析を行った結果、分解微生物はBarkholderia目に分類される細菌群に収束した。水圏における分解性でも同様の傾向であった。これらの成果は生分解性プラスチックは環境中で分解可能でありかつポリマーの組成を変化させることで分解速度を制御できることがわかった。これらの成果は、環境に配慮した石油由来の代替プラスチックとして利用できる高い可能性を持つ。

Research Products

• [Journal Article] Changed bacterial community in the river water samples upon introduction of biodegradable poly(3-hydroxybutyrate) (2020)
  • Author(s): Kadoya R, Tanaka N, Fujita N, Shiwa Y, Taguchi S
  • Journal Title: Polymer Degradation and Stability Volume: 176 Pages: 109144-109144
  • DOI: 10.1016/j.polymdegradstab.2020.109144
  • Peer Reviewed / Open Access
• [Presentation] Poly(enriched lactate-co-3-hydroxybutyrate) depolymerase from Variovorax sp. C34: isolation and characterization (2019)
  • Author(s): Ezema CA, Sun J, Nduko JM, Ooi T, Taguchi S, Matsumoto K
  • Organizer: International Symposium on Biopolymer Synthesis and Degradation
  • Int'l Joint Research
• [Presentation] EXPLORATION OF POLY(D-LACTATE)-DEGRADING BACTERIA AND ANALYSES OF THEIR DEPOLYMERASES (2018)
  • Author(s): Tomohiro Sugiyama, Kodai Watanabe, Toshihiko Ooi, Chiaki Hori, Takuya Isono, Toshifumi Satoh and Ken’ichiro Matsumoto
  • Organizer: Degradation and Stabilization of Polymers (MoDeSt 2018)
  • Int'l Joint Research
• [Presentation] バイオマスを原料とした多元ポリ乳酸の微生物生産 (2017)
  • Author(s): 飯島翠、滝沢憲治、門屋亨介、堀千明、松本謙一郎、大井俊彦、田口精一
  • Organizer: 第6回JACI/GSCシンポジウム
  • Int'l Joint Research