Fractionation of enzyme B by ultrafiltration indicated that most of the response occurred with filtrates containing substances of molecular mass > 100 kDa (Table 3). As the nominal molecular mass cut-off decreased,the amount of stimulation of gas production decreased. Autoclaving destroyed the stimulatory activity of all of the fractions (not shown). The CMCase activity was mostly > 100 kDa, whereas most of the xylanase was < 100 kDa, suggesting a stronger relation between gas production and CMCase rather than xylanase
activity.