LIGNIN AND VERATRYL ALCOHOL ARE NOT INDUCERS OF THE LIGNINOLYTIC SYSTEM OF PHANEROCHAETE-CHRYSOSPORIUM

Phanerochaete chrysosporium is a white rot fungus which secretes a fam ily of lignin-degrading enzymes under nutrient limitation. In this wor k, we investigated the roles of veratryl alcohol and lignin in the lig ninolytic system of P. chrysosporium BKM-F-1767 cultures grown under n itrogen-limited conditions. Cultures supplemented with 0.4 to 2 mM ver atryl alcohol showed increased lignin peroxidase activity. Addition of veratryl alcohol had no effect on Mn-dependent peroxidase activity an d inhibited glyoxal oxidase activity. Azure-casein analysis of acidic proteases in the extracellular fluid showed that protease activity dec reased during the early stages of secondary metabolism while lignin pe roxidase activity was at its peak, suggesting that proteolysis was not involved in the regulation of lignin peroxidase activity during early secondary metabolism. In cultures supplemented with lignin or veratry l alcohol, no induction of mRNA coding for lignin peroxidase H2 or H8 was observed. Veratryl alcohol protected lignin peroxidase isozymes H2 and H8 from inactivation by H2O2. We conclude that veratryl alcohol a cts as a stabilizer of lignin peroxidase activity and not as an induce r of lignin peroxidase synthesis.