2.2. Enzyme extraction and assays
Homogenized samples of soil or litter material were extracted at
4 ◦C for 2 h on an orbital shaker (100 rpm) with 100mMphosphate
buffer, pH 7 (16:1 w/v), filtered through Whatman #5 filter paper
and desalted using PD-10 desalting columns (Pharmacia, Sweden),
according to the supplier’s protocol, to remove inhibitory smallmolecular-
mass compounds. The desalted samples were kept at
−18 ◦C until enzyme activity analysis.