Lignin, cellulose and hemicellulose on the compost/substrate were deter- mined ( 3) by the Van Soest acid detergent fiber method (Van Soest, 1973), employing a digester (Ankom 220 Fiber Analyzer, Ankom Technology, NY, USA) with filter bags F57, at each step of the composting (same samples abovementioned) and in the spent mushroom substrate (SMC) remained at the end of the second flush of mushrooms, randomly obtained from 3 experimental units of each treatment.