Xylanase-, CM-cellulase- and invertase activity in soil: An improved method

We present a method for the quantification of xylanase-, CM-cellulase- or invertase activities of soils. It is possible to offer a simple, sensitive (2.8 μg glucose ml−1 assay mixture) and reproducible determination of the enzyme potentials of soils used by agriculture and forestry. The determination of the activity is carried out via the substrate (xylane, CM-cellulose or sucrose), the reaction is performed at pH 5.5 and 50 C. The reducing sugars are measured colorimetrically after reaction with a potassium ferric hexa-cyanide reagent. Additional investigations confirm the high stability of the soil enzyme cellulase, and further the high correlation of this enzyme, and of the xylanase, with the humus content of 7 different soils.