Thirty-one isolates of the form genera Acremonium and
Cephalosoporium were screened for their ability to excrete
enzymes capable of degrading β-glucans. Most produced both (1
→ 3)- and (1 → 6)-β-glucanases together, although the
yields varied with carbon source used. Surprisingly, higher yields of
(1 → 3)-β-glucanases were often seen from isolates grown on
pustulan, a (1 → 6)-β-glucan which is not hydrolysed by
these enzymes. Lower enzyme yields were generally obtained with
glucose than with either laminarin, a (1 → 3)-β-glucan or
pustulan as carbon sources, suggesting regulation of synthesis by
either catabolite repression and/or induction. However, a few
isolates, most notably Cephalosporium sp. OXF C13 and
Acremonium strictum appeared to have some constitutive-β-glucanase activity. Most of the isolates screened were only
very weakly cellulolytic against carboxymethyl cellulose or filter
paper as substrates.