Study on depression of light-induced color reversion by treatment of mechanical pulps with extracellular crude enzymes from fungi.

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The aim of the study was depression of light-induced color reversion of mechanical pulps (MP) by treatment with extracellular crude enzymes from fungi.1.Screening of fungi having ability for the depression of the color reversion.Method of screening of fungi having ability for the depression of the color reversion with two reductive indicators was developed. Four fungi (No.801,1304,501 and 1701) having the ability for the depression were isolated from natural world. Fungus 1701 depressed 56% of the color reversion of MP.2.Formation of fusants having ability for the depression by protoplast fusion of fungi.Two fusants (1 and 2) were formed by protoplast fusion of Phanerochaete chrysosporium and Fusarium solani. One hundred and eighty one percent of the color reversion of MP could be depressed by fusants 1 and 2 respectively.The ability for the depression has been maintaied until three subcultures, however, the ability was largely decreased after four subcultures.3.Fractionation of enzymes responsible for depression of the color reversion of MP.Extracellular crude enzymes prepared from culture medium of Trametes serialis were separated into four fractions (Fr.1-Fr.4) by ion-exchange chromatography. Each ability of Fr.1 to 4 for the depression was 60,43,35,54%, respectively. Further fractionation of Fr.1 and 4 are being conducted.4.Synthesis of medel compound having functional groups for the color reversion.Guiacylglyceryl-alpha-keto-beta-0-4-coniferylaldehyde ether was tried to synthesize from benzyl acetovanillone through 8 steps. The key compound for the synthesis was prepared from benzy1 acetovanillone through 4 steps in the total yield of 45%. The synthesis of the final compound is being conducted.