INHIBITION OF CELLULOSE SACCHARIFICATION AND GLYCOLIGNIN-ATTACKING ENZYMES OF 5 LIGNOCELLULOSE-DEGRADING FUNGI BY FERULIC ACID

At 5 g/l, ferulic acid, a plant cell-wall phenolic, severely repressed growth of the lignocellulose-degrading fungi Trichoderma harzianum, C haetomium celloulolyticum, Phanaerochaete chrysosporium, Trametes vers icolor and Pleurotus sajor-caju. At 0.5 g/l, however, it slightly stim ulated growth of the latter two organisms, Two classes of extracellula r enzymes involved in cellulose and glycolignin breakdown were assayed : cellulases; and phenol oxidases as laccases. All of the strains depo lymerized cellulose but two (T. versicolor and P. sajor-caju) also sec reted laccases. Laccase-secreting fungal species had normal levels of cellulose saccharification except in the presence of 5 g ferulic acid/ l, whereas saccharification by the other strains was suppressed at all concentrations of the phenolic tested.