- Functional assembly of the foreign carotenoid lycopene into the photosynthetic apparatus of Rhodobacter sphaeroides, achieved by replacement of the native 3-step phytoene desaturase with its 4-step counterpart from Erwinia herbicola. Garcia-Asua, G., Cogdell, R.J., Hunter, C.N. Mol. Microbiol. (2002)