Cellulase induction by cellobiose-octaacetate in Penicillium purpurogenum

Cellulase production by Penicillium purpurogenum strain P-26 was strongly induced by cellobiose-octaacetate (COA) in the presence of microcrystalline cellulose as a co-substrate. COA was solubilized during growth and reducing sugar consisting of multiple components accumulated in the culture broth. Cellulase induction was coupled with consumption of the reducing sugar. A crude protein fraction obtained from the culture supernatant could solubilize COA and the hydrolyzate stimulated cellulase formation by non-induced cells grown on glycerol. Partial purification of the culture supernatant revealed two enzymes, both of which act not only on COA to release soluble reducing sugar and acetic acid but also on other acetylesters to form acetate, indicating that COA was solubilized by acetylesterase secreted in the culture broth and the hydrolyzate, probably partially deacetylated COA, could induce cellulase.