From metabolites to bioprocessing

Every living thing makes chemicals called metabolites.

• Primary metabolites come from the essential pathways that every cell needs to grow and develop: sugars, amino acids, nucleotides.
• Secondary metabolites come from separate pathways. They are not needed to survive, but they help with defence, coping with stress, and attracting animals for pollination and seed dispersal.

Secondary metabolites give us medicines, dyes, food additives, enzymes and vitamins. But nature makes them in small amounts. Bioprocessing makes them in bulk, and pure, in large vessels, bioreactors, which hold on average 100-10,000 litres.

It all began with penicillin. In 1928, Alexander Fleming noticed that a mould contaminating his plate of Staphylococcus aureus bacteria had stopped them growing around it. The mould was Penicillium notatum. Ernest Chain and Howard Florey later showed penicillin's full power as a medicine; it saved countless soldiers in World War II; and all three shared the 1945 Nobel Prize.

Making penicillin in large amounts was a huge challenge. It needed microbiologists, chemical engineers, companies, government laboratories and universities working together, and in solving it, they created bioprocessing.

Bioprocessing, then, combines living systems (cells, or parts of them such as enzymes or chloroplasts) with chemical engineering, to make products on a commercial scale, in vessels called fermenters or bioreactors.