Inactivation of viruses

A bioreactor apparatus for cultivation of cells comprising:

• a) a disposable bioreactor vessel with one or more walls defining an inner volume, at least one port in said one or more walls, wherein said disposable bioreactor vessel is positioned in a rigid support structure;
• and
• b) a heater, capable of heating an amount of culture medium to a target temperature in the range of 55-95° C., said amount of culture medium being confined in or conveyed to said inner volume,
• wherein said heater comprises a plastic or silicone disposable heater conduit fluidically-connected to said at least one port in said one or more walls of said disposable bioreactor vessel, and at least one heating element positioned to heat said disposable heater conduit,
• wherein the at least one heating element is duct-shaped and at least one segment of said disposable heater conduit is confined within the duct-shaped heating element wherein the at least one segment of said disposable heater conduit contains one or more metallic structures and wherein the at least one segment is at least partially surrounded by two or more induction coils, wherein the two or more induction coils are in series.