| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1994: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1993: ¥1,300,000 (Direct Cost: ¥1,300,000)
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| Research Abstract |
An original reaction system (the phase separative reaction system) has been designed for converting native lignins to highly phenolic, functional polymers (lignophenol derivatives). This system is composed of a phenol derivative and concentrated acid which are not miscible at room temperature. The key point of the lignin functionalization process including the phase separative system is that lignin and carbohydrates, which are totally different in structures and reactivities, are modified individually in the different phases : lignin is present in the organic phase and carbohydrates in the aqueous phase. Through the process, lignin was modified selectively at Calpha-positions of side chains, the most reactive sites, to give highly phenolic, light colored diphenylmethane type materials which still retained original interunit linkages formed by the dehydrogenative polymerization during the biosyntheses. The carbohydrates were swollen, followed by partial hydrolysis and dissolution in the acid solution, resulting in the perfect decomposition of interpenetrating polymer network structures in the cell wall. Therefore, the functionalization of lignin and the separation of resulting lignin from carbohydrates were quickly achieved at room temperature, independent of wood species. The molecular weights of lignophenol derivatives can be controlled by mild alkaline treatments. This is due to the selective cleavate of beta-aryl ether linkages with the participation of phenol derivatives introduced into Calpha-positions. Lignophenol derivatives had much higher affinities for proteins, compared with conventional lignin preparations. The lignophenol-protein complex was formed most effectively at the isoelectric point of used protein. Once the complex was formed between lignophenol derivatives and proteins, it was very stable at any pH.The enzymes immobilized on lignophenol derivatives had high activities.
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