Methods and devices for producing biomolecules

A method for producing a biomolecule of interest that is not secreted by the host cells, comprising the steps of a) cultivating host cells to produce the biomolecule of interest and optionally harvesting and resuspending the cells, b) disintegrating the cells by alkaline lysis, c) neutralizing the lysate obtained in step b), whereby a precipitate is formed, d) separating the cleared lysate from the precipitate obtained in step c), e) purifying the biomolecule of interest, wherein a carbonate salt is added in at least one of step a-c), whereby due to acidic conditions at and after step c) CO2 is released and wherein in step d) the precipitate and the lysate are allowed to separate in a clarification device, wherein steps b) to d) are all performed in a continuous mode and wherein the clarification device in which step d) is conducted comprises a container comprising a hollow body, an outlet at the bottom of the device, from which the cleared lysate from step d) is continuously recovered, a tapering top of the container with an outlet on its top, from which the floating precipitate is continuously removed, an inlet positioned between the outlets on top and at the bottom of the container, which is directly connected with neutralization/precipitation tubing, through which the neutralized lysate from step c) already containing flocs with attached gas bubbles continuously enters the clarification device, and a bottom outlet valve, whose opening extent controls the level of the interface lysate-flocs.