Research progresses in the biosynthesis of curcuminoids

Curcuminoids are rare diketone compounds in plants and can be found in the rhizome of Curcuma longa as well as other Zingiberaceae and Araceae. Curcuminoids have been widely used in food and medical area owing to the yellow colors, as well as the antioxidant and many other pharmacological activities. Curcuminoids are a mixture of compounds containing curcumin, demethoxycurcumin and bisdemethoxycurcumin, which have distinct benzene ring substituents. Currently, curcuminoids are exclusively produced through plant extraction, which do not satisfy the meeting of the market demand. Empowered with new synthetic biology tools and metabolic engineering strategies, there is renewed interest in production of curcuminoids using microorganisms. Heterologous production of curcuminoids has been achieved using Escherichia coli, Yarrowia lipolytica, Pseudomonas putida and Aspergillus oryzae via engineering of curcuminoids biosynthesis pathway. In this review, we first describe the biological activities and various applications of curcuminoids. Next, we summarize the biosynthetic pathway of curcuminoids in Curcuma longa and discuss the catalytic mechanisms of curcumin synthases. Then, we thoroughly explore recent advances in the use of distinct microorganisms for the production of curcuminoids with a special focus on metabolic engineering strategies. Finally, we prospect the microbial production of curcuminoids by highlighting some promising techniques and approaches.