An increase of phenol concentration affected the percentages
of phenol removal (Fig. 1) by fungal strains. For concentrations
lower then 6 mM, no significant decreases in
the percentage of degradation were observed. Concentrations
above of this value lowered the percentage of phenol
degradation to levels up to 4%. This behavior is characteristic
of toxic substrate metabolism [12]. The strains LA5,
FIB4, AE2 of Graphium sp. and FE11 of Fusarium sp. presented
the highest degradation percentage when grown in 10
mM of phenol, suggesting a higher phenol tolerance. Studies
have shown that A. fumigatus is able to grow in p-cresol,
4-etilphenol and phenol as sole carbon sources [4,5,13]. Free
or immobilized cells of F. flocciferum have been reported to
use up to 1 g of phenol/l (10.6 mM) [3].