Fixed bed bioreactor and methods of using the same

A fixed-bed bioreactor system for culturing cells in a cell culture media, the system comprising:

• a vessel comprising an interior cavity, and a first opening and a second opening both fluidly connecting the interior cavity to an exterior of the vessel;
• a cell culture substrate disposed in the interior cavity, the cell culture substrate comprising a plurality of layers of porous surfaces configured to culture cells thereon;
• and
• a harvest solution vessel fluidly connected to the interior cavity via one of the first and second openings and configured to contain a harvest solution to be supplied to the interior cavity for harvesting at least one of cells and cell by-products from the interior cavity,
• wherein the fixed-bed bioreactor system is configured to supply the harvest solution to the interior vessel and then to supply a pressurized fluid to the interior cavity via one of the first and second openings, and thereby force the cells or cell by-products from the interior cavity via the other of the first and second openings.