A blow-by gas filtration assembly, fluidically connectable to a crankcase ventilation circuit of an internal combustion engine in order to receive the blow-by gases and to filter them from the suspended particles contained therein, wherein the filtration assembly has an axis (X-X) and comprises: an assembly body comprising a filtration chamber, an inlet mouth for the blow-by gases to be filtered and an outlet mouth for the filtered blow-by gases; ii) a filter group comprising a central cavity through which the blow-by gases is radially crossable, preferably from the outside to the inside; iii) an electric drive that is operatively connected to the filter group in order to command in rotation about the axis (X-X) and to carry out the filtration operations, wherein the electric drive comprises an electric motor that comprises a stator and a rotor; iv) a support and command shaft, which extends along the axis (X-X) and comprises: - a filter portion on which the filter group is mounted; - a command portion on which the rotor is mounted; and - a support portion that is axially positioned between the filter portion and the command portion; v) a support bearing radially engaged to said support portion on the inside and to the assembly body on the outside; wherein the blow-by gas filtration assembly is characterized by the fact that the filter group and the filter portion comprise a filter thread and a shaft thread, respectively, screwable to one another, wherein the filter group screwed to the shaft axially engages with the support bearing, wherein said axial engagement between the filter group and support bearing prevents additional screwing of the filter group. an assembly body comprising a filtration chamber, an inlet mouth for the blow-by gases to be filtered and an outlet mouth for the filtered blow-by gases; ii) a filter group comprising a central cavity through which the blow-by gases is radially crossable, preferably from the outside to the inside; iii) an electric drive that is operatively connected to the filter group in order to command in rotation about the axis (X-X) and to carry out the filtration operations, wherein the electric drive comprises an electric motor that comprises a stator and a rotor; iv) a support and command shaft, which extends along the axis (X-X) and comprises: - a filter portion on which the filter group is mounted; - a command portion on which the rotor is mounted; and - a support portion that is axially positioned between the filter portion and the command portion; v) a support bearing radially engaged to said support portion on the inside and to the assembly body on the outside; ii) a filter group comprising a central cavity through which the blow-by gases is radially crossable, preferably from the outside to the inside; iii) an electric drive that is operatively connected to the filter group in order to command in rotation about the axis (X-X) and to carry out the filtration operations, wherein the electric drive comprises an electric motor that comprises a stator and a rotor; iv) a support and command shaft, which extends along the axis (X-X) and comprises: - a filter portion on which the filter group is mounted; - a command portion on which the rotor is mounted; and - a support portion that is axially positioned between the filter portion and the command portion; - a filter portion on which the filter group is mounted; - a command portion on which the rotor is mounted; and - a support portion that is axially positioned between the filter portion and the command portion; v) a support bearing radially engaged to said support portion on the inside and to the assembly body on the outside; wherein the blow-by gas filtration assembly is characterized by the fact that the filter group and the filter portion comprise a filter thread and a shaft thread, respectively, screwable to one another, wherein the filter group screwed to the shaft axially engages with the support bearing, wherein said axial engagement between the filter group and support bearing prevents additional screwing of the filter group.