Cellulase production by a Cellulomonas sp., isolated in 1985 from forest humus
soil along the border of the Caspian Sea in Iran, was investigated. This strain secreted
endo-and exo-cellulases in the culture medium, but some of the enzymes produced
remained cell membrane bound. Cell bound enzymes were released by various
treatments. The highest amount of endo-glucanase (up to 95%) and exo-glucanase
(62%) was released when the cells were treated with 1% Tween 80 for 300 and 60
minutes, respectively. No extracellular or cell membrane bound ?-glucosidase was
obtained. Optimum temperature for the endo-glucanase and exo-glucanase activities
was 50°C and optimum pH was 7 for both enzymes. Thermal stability of enzymes was
measured at 30 to 50°C and was compared with that of endo- and exo-glucanses from
mesophilic fungi such as Neurospora crassa, Trichoderma viri& and Pencillium
funiculosum. It was found that the thermal stability of endo- and exo-glucanases from
Cellulomntas sp. strain "0"w as the same as that of fungal enzymes up to 37?C,
however, at higher temperatures these enzymes lost their activities faster than the
fungal cellulases