Multicompartment bag for cultivation of cells

A method for cultivation of cells, comprising the steps of:

• a) providing a flexible plastic bag for cultivation of cells, comprising:
• a top wall film and a bottom wall film, each having an inside and an outside, sealed to each other inside-to-inside by durable weld seams, optionally via one or more side wall films, to form a bag with an inner volume delimited by said durable weld seams;
• one or more ports for introduction and withdrawal of fluids to or from the inner volume;
• one or more frangible weld seams joining the insides of said top and bottom wall films, dividing said inner volume into a plurality of cultivation compartments;
• b) introducing culture media and cells in at least one of said cultivation compartments;
• c) cultivating the cells in said cultivation compartment to provide a cell culture;
• d) breaking a frangible weld seam between said cultivation compartment and an adjacent cultivation compartment by pulling apart said top and bottom wall films over said frangible weld seam in a direction essentially perpendicular to said frangible weld seam, so as to combine the two cultivation compartments into a larger cultivation compartment;
• e) cultivating the cells in said larger cultivation compartment.