Escherichia coli carotenoid lycopene

It should be noted that the carotenoids pictured here are, in general, not final major products in the biosynthetic pathways of organisms and are usually cy-clized, hydroxylated, methylated, or otherwise altered in the organism. With the exception of lycopene, these carotenoids usually accumulate in mutants having blocks in the pathway or when portions of the carotenoid pathway are expressed in Escherichia coli, a carotenoid-less bacterium. Other carotenoid and terpenoid desaturations are discussed later. 

---