SCREENING OF LIGNIN-DEGRADING FUNGI AND THEIR LIGNINOLYTIC ENZYME-ACTIVITIES DURING BIOLOGICAL BLEACHING OF KRAFT PULP

In the first step of screening, many strains of lignin-degrading fungi were isolated by using a medium containing both beech (Fagus sp.) wood meals and guaiacol. It was tried to select active lignin-degrading fungi from the isolates with beech wood-meals medium. Eleven strains of new isolates showed higher ligninolytic activities and selectivities than did typical lignin-degrading fungi, Phanerochaete chrysosporium and Coriolus versicolor, although most of them showed lower wood-decaying activities. Eight of the 11 strains showed higher bleaching abilities of hardwood unbleached kraft pulp than did the 2 known fungi. Manganese peroxidase (MnP) exhibited great activity compared with those of lignin peroxidase and phenol oxidase in bleaching cultures of 7 stains which could bleach kraft pulp. The higher brightness increase was observed in fungal treated pulp, the higher MnP activities were detected in the cultures.