Fibril formation from cellulose by a novel protein from Trichoderma reesei: A non-hydrolytic cellulolytic component?

A low molecular weight protein, named fibril-forming protein (FFP), was isolated from the culture supernatant of Avicel-grown Trichoderma reesei. The protein was purified to homogeneity and it exhibited a molecular weight of 11,400 Da. Low amounts of this protein caused apparently non-hydrolytic disruption of filter paper, releasing fibrils without any detectable release of reducing sugars. It displayed no hydrolytic activity on carboxymethylcellulose (CMC), p-nitrophenyl-beta-D-glucoside (pNPG) or 4-methylumbelliferyl cellobioside. The pH optimum of the protein was between 4 and 5. The temperature optimum was 40 degrees C and the computed activation energy (E-a) for the filter paper disruption process was 4.18 kcal/mol, suggesting disruption of non-covalent bonds. It had no immunological cross reactivity with reported cellulase components of T. reesei.