EXTRACELLULAR ENZYME-PRODUCTION AND SYNTHETIC LIGNIN MINERALIZATION BY CERIPORIOPSIS-SUBVERMISPORA

The ability of the white rot fungus Ceriporiopsis subvermispora to min eralize C-14-synthetic lignin was studied under different culture cond itions, and the levels of two extracellular enzymes were monitored. Th e highest mineralization rates (28% after 28 days) were obtained in cu ltures containing a growth-limiting amount of nitrogen source (1.0 mM ammonium tartrate); under this condition, the levels of manganese pero xidase (MnP) and laccase present in the culture supernatant solutions were very low compared with cultures containing 10 mM of the nitrogen source. In contrast, cultures containing a limiting concentration of t he carbon source (0.1% glucose) showed low levels of both enzymes and also very low mineralization rates compared with cultures containing 1 % glucose. Cultures containing 11 ppm of Mn(II) showed a higher rate o f mineralization than those containing 0.3 or 40 ppm of this cation. L evels of MnP and laccase were higher when 40 ppm of Mn(II) was used. M ineralization rates were slightly higher in cultures flushed daily wit h oxygen, whereas laccase levels were lower and MnP levels were approx imately the same as in cultures maintained under an air atmosphere. Th e presence of 0.4 mM veratryl alcohol reduced both mineralization rate s and MnP levels, without affecting laccase levels. Lignin peroxidase activity was not detected under any condition. Addition of purified li gnin peroxidase to the cultures in the presence or absence of veratryl alcohol did not enhance mineralization rates significantly.