Summary: The secretion of several hemicellulolytic enzymes and endoglucanase was studied in S- and P-group strains of a wood-rotting pathogen, , using enzyme activity assays and isoelectric focusing. In liquid cultures supplemented with birch sawdust or pure xylan, both strains of the fungus produced xylanases, mannanases, endoglucanases and α-galactosidases. Low activities were detected in cultures containing only glucose as a carbon source. When S-strain cultures were provided with a cart matrix, protein secretion to the culture medium started earlier and was significantly increased compared to free cell cultures. This was not the case with the P-strain. In both strains of the pH of the birch sawdust culture medium fell within 12 d to below 3.5, and then started to increase towards the end of the cultivation period. The increase in pH appeared to corresprelate with the formation of hemicellulolytic and endoglucanase activitie. The isoenzyme patterns of xylanase, mannanase and endoglucanase were typical for P- and S-strains. In P-strain cultures containing xylan, a xylanase with an alkaline pl value was induced which, however, was absent when the strain was grown with the birch sawdust substrate. In the P-strain the mannanase pattern at the early stage of growth was comparable to that of t S-strain at the later stages of growth on birch sawdust medium. Later in the growth of the P-strain, this pattern was replaced by mannanases with more acid pl values. The relative intensities of the individual endoglucanases varie between the P- and S-strains.


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