Once the correct insulin-expressing cell is identified, then can grow up large numbers of bacteria in a broth made of amino acids, vitamins and sugar. Therefore large amounts of insulin protein can be made quickly (bacteria double in mass about every 40 minutes).

Burst the cells and then purify the insulin from the rest of bacterial proteins with chromatography (selective sticking and elution of insulin from special beads with various properties).

Package the purified, sterile insulin into vials or syringes for treating patients.