Microorganisms. T. reesei QM9414, kindly supplied by
Mary Mandels, U.S. Army Natick Development Center,
Natick, Mass., was continuously maintained on delignified
wheat straw (WS) agar medium in petri plates. The WS agar
medium was specially designed for this purpose. The nutrients
in the medium are described below. In one of the
colonies, a sector showing high hydrolytic activity was noticed. The mutation occurred due to continuous subculturing
on WS medium (usually cultures of T. reesei are maintained
on potato-dextrose agar). The new mutant was transferred to
similar medium, and in five further transfers a stable mutant
was obtained. This new mutant was tentatively named
QMY-1.