β-carotene

β-carotene is a common carotenoid that derives from the xanthophyll group known for its characteristic orange color. β-carotene can be found in fruits and vegetables, for example carrots. β-carotene is a provitamin to vitamin A, which means that during the right circumstances β-carotene can be catalyzed further to produce vitamin A. Vitamin A has several important health aspects which includes skin, mucus membrane and most common to people a good effect on eyes and vision. Studies have shown that the carotenoid can prevent aging of the brain and stimulate it to keep its capability of memory when a high ascorbic acid concentration also is present ⁽¹⁾. The health aspects were an important part of our choice to produce β-carotene.

Methods

The gene CrtY that is responsible for translating the protein lycopene cyclase was obtained from the zeaxanthin operon provided by Slovenia iGEM team 2010. Production of β-carotene is initiated through the catalytic reaction done by the enzyme lycopene cyclase which uses the precursor lycopene.

Results (Summary)

Beta carotene production was proven through the production of our operon containing zeaxanthin. Since production of zeaxanthin relies on beta carotene as a precursor we could simultaneously prove that we successfully had produced both zeaxanthin and beta carotene through liquid-liquid separation and spectrophotometry (read spectrophotometry of zeaxanthin for more results)

Results (Bio-bricks)

We realized that there were a lot of components in the carotenoid pathway that we were in need of in the beginning of the project that were missing in the registry. Therefore after obtaining the zeaxanthin operon from Slovenias iGEM team 2010 we directly proceeded with isolating of the genes as basic components in order to send them to the registry.