USE OF ENZYMES IN DEINKED PULP BLEACHING

To comply with government's environmental policies and to satisfy the requests of the consumers, recycling of waste paper is essential for reducing the Consumption of virgin fibers in pulp and paper industry. However, the poor optical properties of recycled fibers restrict their use in value-added papers. Enzymes, such as lipase and laccase, represent an interesting alternative. The detachment of contaminants and ink particles, as well as the chemical modifications induced by these enzymes, could increase brightness and reduce residual ink concentration. The main objectives of the present study were to assess the effectiveness of deinking and bleaching with lipase and laccase. The optimum process conditions selected for lipase were of 10 IU/g (International Unit/gram of oven-dry pulp), without pH adjustment.