The present invention relates to a microorganism-containing preparation for biologically decomposing the biomass containing residues of toxic agents, hazardous substances resulting from pharmaceutical industry, from the production of biogas or bioethanol-biodiesel fuel. The preparation contains one or more mixed cultures from the National Collection of Agricultural and Industrial Microorganisms, deposited under the registration number NCAIM 135/2010, NCAIM 136/2010 or NCAIM 137/2010, or one or more of the microorganisms comprised in said mixed cultures, together with the biologically compatible carrier materials, used by the organisms, as the case may be. The preparation is used for the biological decomposition of biomass by mixing it with the preparation, in aerobic conditions and with additions of materials containing lignocellulose, there being obtained composts.
