Shoichi Miyawaki

Biobleaching of unbleached and oxygen-bleached hardwood kraft pulp by culture filtrate containing manganese peroxidase and lignin peroxidase from Phanerochaete chrysosporium

Unbleached and oxygen-bleached hardwood kraft pulp (UKP and OKP), respectively, were bleached with a culture filtrate containing manganese peroxidase (MnP) and lignin peroxidase (LiP) fromPhanerochaete chrysosporium Burds. The brightness increases of UKP upon biobleaching with the culture filtrate with and without MnSO4 were the same. The brightness increase of OKP with MnSO4 decreased to about half that seen without MnSO4. Changes in the brightness of UKP and OKP by treatment with the culture filtrate were determined. The brightness increased sharply by about eight points during the first 3h. The 3-h treatment was repeated seven times. The brightness increased linearly with the bleaching of UKP. On bleaching of OKP, the brightness increased slowly and stopped at about 78%.