Creating carotenoid diversity in E. coli cells using combinatorial and directed evolution strategies

Carotenoids represent a structurally diverse class of pigments with important biological functions and commercial applications. Biosynthesis of carotenoids has been studied on a molecular level for the core pathways and recombinant hosts have been engineered for heterologous carotenoid production. This paper summarizes our efforts on accessing novel carotenoid compounds in engineered E. coli by altering the catalytic activities of enzymes using in vitro evolution, by exploring the catalytic promiscuity of known carotenoid enzymes and by mining for novel enzymes in microbial genome sequences.