| Project/Area Number |
63850183
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| Research Category |
Grant-in-Aid for Developmental Scientific Research (B).
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| Allocation Type | Single-year Grants |
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| Research Field |
高分子合成
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
DOI Yoshiharu Tokyo Institute of Technology, Associate Professor Research Lab. of Resources Utilization., 資源化学研究所, 助教授 (40016639)
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| Co-Investigator(Kenkyū-buntansha) |
NAKAMURA Yoshiyuki Tokyo Institute of technology, Research Associate Research Lab. of Resources Uti, 資源化学研究所, 助手 (90155870)
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| Project Period (FY) |
1988 – 1990
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| Project Status |
Completed (Fiscal Year 1990)
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| Budget Amount *help |
¥8,300,000 (Direct Cost: ¥8,300,000)
Fiscal Year 1990: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1989: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 1988: ¥6,100,000 (Direct Cost: ¥6,100,000)
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| Keywords | Microbial polyesters / Copolyesters / Bioplastic / Biodegradable polymer / Fermentation production / Functional material / Microbial synthesis / Alcaligenes eutrophus / 機能材料 / 石油資化菌 / 生分解性プラスチック / 発酵生産プタセス / 生物分解性ポリエステル |
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| Research Abstract |
A variety of microorganisms produce and accumulate a polyester in their cells as an energy source. The microbial polyester is a thermoplastic with biodegradable and biocompatible properties. Under optimal fermentation conditions, a microorganism produces a large amount of polyester at a high efficiency from alkanoic acids and alcohols. The content of polyester in dried cells increases up to 80 wt%.
Recently, we have found that a new copolyester of 3-hydroxybutyrate (3HB) and 4-hydroxybutyrate (4HB) is produced by Alcaligenes eutrophus from various carbon sources of 4-hydroxybutyric acid, 1,4-butanediol, and butyrolactone. The composition of copolyesters varies from 0 to 60 mol-% 4HB units, depending on both fermentation conditions and carbon sources supplied. The physical and mechanical properties of P (3HB-co-4HB) are strongly dependent upon the copolymer compositions. The crystallinity of copolyester decreases with the 4HB fraction, and the strain of copolyester film increases from 5 to 444% at 16mol% 4HB. The copolyesters of over 40 mol% 4HB exhibit the mechanical properties of an elastic rubber. These copolyesters behave as thermoplastics with a melting point of 140-180^ﾟC and can be processed into transparent film and strong fiber by conventional extrusion and moulding equipment.
The products of P (3HB-co-4HB) copolyesters are biodegradable in soil and activated sludge. The copolyester films were degraded after 6 weeks at 20-25^ﾟC in soil. Some microorganisms excrete extracellular depolymerases to degrade environmental polyesters into non-toxic monomers and utilize the decomposed compounds as nutrients. These microbial copolyesters have attracted much attention as environmentally degradable bioplastics for a wide range of agricultural, marine, and medical applications.
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