Chapter 9 - Metabolic engineering of astaxanthin pathway and heterologous production in novel organisms

Abstract

Astaxanthin, a ketocarotenoid and a potent antioxidant, has multiple applications in aquaculture, nutraceutical, cosmetic, food, and pharmaceutical industries. The demand for natural astaxanthin is increasing owing to its beneficial effects over synthetic one. Commercial production of astaxanthin from potential natural sources has been established and got approval as food supplement from regulatory agencies like FDA and other European agencies. However, the cost of production of natural astaxanthin limited its market share to <5% despite technical advancements in production systems and cultivation conditions. For enhancing cost-effective production of astaxanthin, metabolic engineering strategies were explored in bacteria, yeast, algae, and plants. Most of the alterations are related to overexpression or heterologous expression of the key genes encoding beta-carotene ketolase and beta-carotene hydroxylase enzymes involved in astaxanthin biosynthesis. Metabolic engineering approaches used in a variety of hosts for astaxanthin biosynthesis are presented in the chapter.