Escherichia coli can be genetically engineered to produce the sweet-tasting protein brazzein in laboratory systems.
Brazzein is a small protein originally isolated from the West African fruit of Pentadiplandra brazzeana. It is intensely sweet compared with sucrose and remains useful to researchers exploring protein-based sweeteners. Because the natural fruit provides only limited amounts, scientists have inserted the brazzein gene into microorganisms such as E. coli so the protein can be made through fermentation.
E. coli is widely used in biotechnology because its genetics are well understood, it grows quickly, and foreign genes can be expressed in engineered strains. The laboratory strains used for production are not the same as disease-causing strains that can contaminate food.
A common mix-up is confusing brazzein with thaumatin, another intensely sweet protein from Africa. They come from different plants and have different protein sequences. Producing a protein sweetener in bacteria also does not mean the bacterium naturally makes it; the production depends on inserted genetic instructions.