Genes isolated from Methylomonas sp. 16a have been determined to play a role in the carotenoid biosynthetic pathway. Specifically, crtN2 gene has the ability to produce omega-aldehyde functional groups on carotenogenic substrates, while the ald gene produced omega carboxyl functional groups. These genes will be useful for production of high levels of functionalized carotenoid compounds, especially those produced in microorganisms which metabolize single carbon substrates.