A process for the production of an enzymatic cocktail with a cellulolytic microorganism comprises two phases: a phase a) for growth of said microorganism in a closed reactor in the presence of a carbonaceous growth solution; a phase b) for the production of said enzymatic cocktail carried out with a supply of carbonaceous production solution the concentration of carbonaceous substrate of which is in the range 150 to 400 g/L, said carbonaceous production solution comprising a carbonaceous inducer substrate; characterized in that said carbonaceous inducer substrate is a liquid residue obtained from a step for pre-treatment of lignocellulosic materials, the C5 sugar oligomers of which represent at least 1% by weight of the total sugars present in said liquid residue, and at least 0.3% by weight of the total sugars present in said carbonaceous production solution.