Measurement of cellulase and xylosidase activities in feat using a sensitive fluorogenic compound assay

We applied fluorogenic methylumbelliferyl compounds to measure enzyme activities (beta-glucosidase, cellobiohydrolase, and beta-xylosidase) in a wetland peat. The enzyme activities showed substrate saturation around 400 mu M and approximate linearity for at least 100 minutes incubation time. The effects of phenolics and toluene on the enzymes were small. All enzyme activities increased with increasing incubation temperature. Beta-glucosidase and beta-xylosidase showed optimal activities in an acidic condition (pH 5), while cellobiohydrolase had the highest activity in a neutral pH. The method would be effective in samples with low enzyme activities and interferences from organic compounds.