Bioreactor

A sealed vessel that holds living cells or microbes in precisely controlled conditions so they grow or make a product.

• Sensors and controls keep temperature, acidity, dissolved oxygen, nutrients and mixing within narrow ranges.
• Everything must stay sterile; a single contaminating microbe can outgrow the culture and ruin a batch worth millions.
• They make vaccines, antibody drugs, enzymes and cultivated meat; the largest drug-making tanks for animal cells hold about 20,000 litres.
• Scale-up is hard: in big tanks oxygen and nutrients mix unevenly and stirring stresses cells, so flask results often don't carry over.