Change in oxidation state of manganese atoms in kraft pulp during biological bleaching with white-rot fungusPhanerochaete sordida YK-624

Abstract

Change in the oxidation state of manganese atoms in unbleached hardwood kraft pulp (UKP) during the biological bleaching of UKP withPhanerochaete sordida YK-624 was determined by the electron spin resonance (ESR) method. The spectrum of Mn(II), which reveals hyperfine splitting, was not observed in the ESR analysis of UKP, but the spectrum for manganese dioxide was observed. After fungal treatment of UKP withP. sordida YK-624, the spectrum of Mn(II) was detected. The reduction of manganese dioxide was triggered by the increase in NADPH-dependent ferrireductase activity. It is concluded that the manganese dioxide dominant in UKP was reduced byP. sordida YK-624 to Mn(II), which stimulates the production and function of manganese peroxidase.