Most of Novo Nordisk's products are made by fermentation using microorganisms such as selected strains of bacteria and microfungi. The majority of these have been genetically-modified enabling for example yeast cells – like those used to bake bread – to produce human insulin, an E. coli bacterium to produce human growth hormone, or a microfungus to produce a detergent enzyme capable of removing grease stains from clothes in lukewarm water.

Microorganisms at work
The fermentation process takes place in large closed tanks in which a microorganism strain is added to a liquid nutrient substrate consisting of water, nutrient salts and different agricultural products, e.g. soya bean grits, sugar, and potato or maize starch.

The microorganisms act as tiny factories, utilizing the nutrients in the substrate to make our products. Considerable quantities of energy are needed to sterilize the tanks and nutrients with steam, and during the fermentation process the tanks are aerated with large amounts of sterile air.

Recovery and liquid waste
On completion of fermentation the product is recovered through a series of filtering and purification steps using filter aids and salts.

The end product constitutes only a small proportion of the contents of the fermentation tank. The remainder is made up of microorganisms, nutrient residues and large quantities of water. The most concentrated part of this liquid waste, called spent biomass, is used as agricultural fertilizer. The remainder is treated in biological waste water treatment plants before discharge. At the factory in Franklinton all waste water is used to irrigate agricultural land. Figure 6 gives an overview of the production process.