Biotechnol. Bioeng. doi:10.1002/bit.22502 (2009)

Researchers have engineered bacteria to produce useful levels of putrescine, a key ingredient in the production of plastics and industrial chemicals. Putrescine — a natural breakdown product of amino acids that contributes to the characteristic odour of rotting flesh — has historically been manufactured from petrochemicals through environmentally harsh methods.

To develop a more sustainable process, Sang Yup Lee and his colleagues at the Korea Advanced Institute of Science and Technology in Daejeon, Republic of Korea, boosted putrescine production in Escherichia coli. Their method involved inactivating the metabolic pathways that use and degrade putrescine, and amplifying the production of an enzyme that makes it from its precursor, ornithine. In high-cell-density cultures, the bacteria can produce up to 24.2 grams of putrescine per litre in about 32 hours.