1994 Fiscal Year Final Research Report Summary
Stereospecific Synthesis of Biodegradable Segment for Design of Biodegradable Polymer and Chemistry of Biodegradation
| Project/Area Number |
05650863
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
有機工業化学
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| Research Institution | Keio University |
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Principal Investigator |
MATSUMURA Shuichi Keio University, Faculty of Science and Technology, Professor, 理工学部, 教授 (30051874)
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| Project Period (FY) |
1993 – 1994
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| Keywords | Biodegradable Polymer Design / Biodegradability / Vinyl Alcohol Block / Polyvinyl Alcohol / Degrading Microbe / Enzyme / Dehydrogenase / Stereoregularity |
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| Research Abstract |
Poly (vinyl alcohol) (PVA) is the only substance which is confirmed to be biodegradable in the class of polyvinyl-type synthetic polymers. Vinyl alcohol blocks may be readily incorporated as biodegradable segments into a functional polymer chain by the copolymerization of functional vinyl monomers. But the minimum struture of vinyl alcohol block necessary to react with PVA-degrading enzyme has not yet been clearly estimated. In this report, vinyl alcohol blocks were prepared and analyzed with respect to the block length and its stereochemical configuration which is expected to react as a biodegradable segment in the functional polymer chain. That is, three vinyl alcohol oligomers, isotactic-type trimer (i-3VA) , atactic-type trimer (a-3VA) and isotactic-type pentamer (i-5VA) were prepared. The biodegradability of these compounds was compared by measuring biologycal oxygen demand (BOD) using symbiotic PVA degrading microbes (PVA-IMX) , isolated PVA-assimilating strain (Alcaligenes faecalis KK314 and Pseudomonas sp.113 P3) .
It was found that the vinyl alcohol block having a chain length of more than 3-5 monomer units and having an isotactic structure, in which all hydroxyl groups are lacated on the same side of the zig-zag plane, is needed in order to be accepted as a substrate for PVA-assimilating microbes and enzyme. It was also found that substrate specificity of PVA-dehydrogenase obtained from both Alcaligenes faecalis KK314 and Pseudomonas sp. 113 P3 was quite similar. A significant increase in enzymatic biodegradability of poly (sodium carboxylate) containing vinyl alcohol blocks was observed for a vinyl alcohol block length of more than about 3. In conclusion, it is found that the isotactic PVA having a vinyl alcohol chain length of more than 3-5 is needed to be cleaved by PVA-degrading microbes as a biodegradable segment.
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