An enzyme (CelZ) from Clostridium stercorarium has an almost identical structure. When deleting the adherent first CBM (together with the second), the enzyme got thermolabile, i.e. it hat almost no enzymatic activity at 60 °C, however the activity could be measured at lower temperature (Riedel et al., FEMS Microbiol Let. 164:261-267 (1998)). Have the authors tried to check for activity at lets say...