The Galactose Oxidase Air Oxidation of Galactomannans for Use as Paper Strengthening Agents

Abstract

Galactomannans are a widely used polysaccharide. In this study, galactomannans were oxidized using galactose oxidase, aided by horseradish peroxidase (HRP) and catalase. Then, a small amount of hydrogen peroxide was used to oxidize the reaction products in order to prepare the paper strengthening agents. The optimal oxidation conditions were investigated according to the properties of the paper, which included the galactose oxidase dosages and concentrations of hydrogen peroxide. It was determined that, when the enzyme dosage was 50 U/g and the hydrogen peroxide concentration was 0.4%, the properties of the paper could be evidently improved with a lower hydrogen peroxide addition. When 1.5% oxidized galactomannans were used, the tensile index and folding endurance were found to have been increased by 23.50% and 110.31%, respectively, when compared with the control. In regard to the recycled paper, the increases were observed to have reached 22.19% and 175%, respectively. The results of the molecular weight, FT-IR, and CP/MAS13C-NMR indicated that a percentage aldehyde and carboxyl groups had been added to the galactomannans.