Carotenoids, Microbial Processes

Abstract

Carotenoids are used commercially as food colorants, feed supplements, nutraceuticals, and for cosmetic and pharmaceutical purposes. However, only a handful of the more than several hundred different carotenoids identified in nature can be obtained in useful quantities by chemical synthesis, extraction from their natural sources or microbial fermentation. The current global market for all commercially used carotenoids is expected to rise at an average annual growth rate of 2.9% reaching over $1 billion in 2009. The over‐the‐counter and pharmaceutical sector has become a new market for carotenoids and, together with an increasing demand for carotenoids in traditional feed and food applications, pushes efforts for the production of diverse carotenoid structures in useful quantities. As an alternative to chemical synthesis and extraction from natural sources, microbial processes are being currently developed for the production of carotenoids. In this article we will discuss the recent progress made in the development of microbial processes for carotenoid production.

Heterologous Carotenoid-Biosynthetic Enzymes: Functional Complementation and Effects on Carotenoid Profiles in Escherichia coli

“…These structurally diverse pigments have different biological functions such as coloration, photo protection, light harvesting, and serving as precursors for many hormones (1). Carotenoids are commercially used as food colorants and animal feed supplements, and more recently, they are being used as nutraceuticals and cosmetic and pharmaceutical compounds (2). The increasing industrial importance of carotenoids has led to renewed efforts in developing bioprocesses for large-scale production of a range of carotenoids, including lycopene, ␤-carotene, and other more structurally diverse carotenoids (3)(4)(5)(6).…”

“…This combinatorial approach basically relies on the functional coordination/complementation of pathway enzymes from different sources in a heterologous host (2,8,9). Among the carotenogenic microorganisms (2,8), Pantoea (formerly Enterobacter) is a well-known carotenogenic bacterium that produces zeaxanthin and its derivatives (8).…”

“…This combinatorial approach basically relies on the functional coordination/complementation of pathway enzymes from different sources in a heterologous host (2,8,9). Among the carotenogenic microorganisms (2,8), Pantoea (formerly Enterobacter) is a well-known carotenogenic bacterium that produces zeaxanthin and its derivatives (8). The carotenogenic pathway consists of 6 enzymes: geranylgeranyl diphosphate (GGPP) synthase CrtE, phytoene synthase CrtB, phytoene desaturase CrtI, lycopene cyclase CrtY, ␤-carotene hydroxylase CrtZ, and the zeaxanthin glucosyltransferase CrtX (Fig.…”