Production of Microbial Food Colorants

Halophilic archaea or haloarchaea are extremophilic microorganisms that require high salt concentrations to thrive. In their natural hypersaline environment, they are constantly exposed to osmotic and oxidative stress as well as to high levels of radiation. Haloarchaea has developed different adaptative strategies at the molecular level to cope with these harsh conditions, including hyperpigmentation. Related to haloarchaeal pigmentation, most of the species synthesize mainly the C50 pink carotenoid called bacterioruberin and its precursors, monoanhydrobacterioruberin and bisanhydrobacterioruberin. Their vibrant color and extraordinary antioxidant properties have attracted attention across the researchers during the last few years. The main objective of this chapter is to present a review of the main characteristics of haloarchaeal carotenoids and their potential applications in the food industry as colorants, antioxidants and interesting bio-additive for the design of functional foods due to their reported antitumoral, immunomodulatory and antioxidant as biological activities. Highlights and challenges related to their mid- and large-scale production are also discussed.