Carotenoids

Carotenoids are valuable biotechnological compounds because of their health-promoting properties and their use as food and feed additives. Carotenoid biosynthesis is a widespread trait in fungi, and the easy detection of carotenoid mutants have made them useful visual markers for genetic analysis in model species. These features have attracted the interest of researchers towards the analysis of their biosynthetic pathways. The genetics and biochemistry of fungal carotenogenesis have reached high levels of knowledge for three biosynthetic carotenoid pathways: those for β-carotene in zygomycetes, neurosporaxanthin in ascomycetes, and astaxanthin in basidiomycetes. The information on astaxanthin biosynthesis is presented in another chapter. This chapter reviews the current knowledge on the genes and enzymes responsible for β-carotene and neurosporaxanthin biosynthesis in some model fungi, describes the available information on the relevant regulatory factors that affect the production of them, and their potential biological roles. Less information is available on the biosynthesis of other fungal carotenoids, which are also briefly reviewed.