Microbial cells accumulate pigments under certain culture conditions, which have very important industrial applications. Microorganisms can serve as sources of carotenoids, the most widespread group of naturally occurring pigments. More than 750 structurally different yellow, orange, and red colored molecules are found in both eukaryotes and prokaryotes with an estimated market of $ 919 million by 2015. Carotenoids protect cells against photooxidative damage and hence found important applications in environment, food and nutrition, disease control, and as potent antimicrobial agents. In addition to many research advances, this paper reviews concerns with recent evaluations, applications of microbial pigments, and recommendations for future researches with an understanding of evolution and biosynthetic pathways along with other relevant aspects. 1. Introduction The human eye does not see in black and white! Color is one of the first characteristics perceived by the human senses. It is integral to the interface between people and nature. Nature is rich in colors obtained from fruits, vegetables, roots, minerals, plants, microalgae, and so forth, and due to their origin from biological material they are often called “biocolors” . Humans have traditionally preferred natural sources to add colors to food, clothing, cosmetics, and medicines. Among the molecules produced by microorganisms are carotenoids, melanins, flavins, phenazines, quinones, and bacteriochlorophylls, and more specifically monascins, violacein, and indigo [2, 3]. 2. Pigments from Microbes A variety of natural and synthetic pigments are available. Naturally derived pigments are represented by carotenoids, flavonoids (anthocyanins), and some tetrapyrroles (chlorophylls and phycobiliproteins). Lately, interest in synthetically derived pigments has decreased due to their toxic, carcinogenic, and teratogenic properties and attention towards microbial sources has increased as a safe alternative [2, 4–7]. Several species of algae, fungi, and bacteria have been exploited commercially for the production of pigments [2, 5, 7]. An inventory ofmicroorganisms producing different pigments is given in Table 1. An ideal pigment producing microorganism should be capable of using a wide range of C and N sources, must be tolerant to pH, temperature, and minerals, and must give reasonable color yield. The nontoxic and nonpathogenic nature, coupled with easy separation from cell biomass, are also preferred qualities. Microbial pigments have many advantages over artificial and inorganic colors. One relates
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