Date of Award


Document Type

Honors Thesis (Open Access)


Colby College. Chemistry Dept.


Ron Peck

Second Advisor

Rebecca Conry


Carotenoids are used as natural colorants and have been shown to have numerous health benefits, making these molecules highly desirable in the aquaculture, pharmaceutical, and nutraceutical markets. There is increasing consumer demand for the natural synthesis of carotenoids, but current methods are limited by the cost and difficulty of extraction from organisms. The halophilic archaeon Haloferax volcanii is amenable to extraction and has an endogenous carotenoid biosynthetic pathway that culminates in the accumulation of the carotenoid bacterioruberin; however, H. volcanii also synthesizes important precursors that can be converted into more highly-desired carotenoids, such as β-carotene and astaxanthin, in the presence of enzymes that catalyze these reactions. In this work, we show that the carotenoid biosynthetic pathway in H. volcanii can be manipulated to increase overall carotenoid production and to synthesize carotenoids of high demand. Insertion of a highly active promoter resulted in significantly increased lycopene and phytoene production, while expression of a nonnative gene encoding the lycopene cyclase enzyme allowed for β-carotene synthesis. These results may inform future work investigating the use of H. volcanii for the bioproduction of carotenoids on an industrial scale.


carotenoids, halophiles, archaea, biosynthesis