(EN) The invention relates to a preparation exhibiting enzymatic activity characterised in that it is obtainable by aerobic fermentation, in a suitable medium, of a Bacillus Stearothermophilus strain selected from the strains NCIMB 40221 and 40222 and mutants and variants thereof having substantially the same capability of producing this preparation as strains NCIMB 40221 and 40222, the preparation having the capability of delignifying wood pulp at a temperature of at least 65oC and a pH of at least 9. The production of this preparation, the isolated NCIMB 40221 and 40222 strains, treated wood pulp and products therefrom and nucleotide probes and antibodies for identifying the enzyme in the preparation of this invention are also included.