Challenges and tackles in metabolic engineering for microbial production of carotenoids.

Naturally occurring carotenoids have been isolated and used as colorants, antioxidants, nutrients, etc. in many fields. There is an ever-growing demand for carotenoids production. To comfort this, microbial production of carotenoids is an attractive alternative to current extraction from natural sources. This review summarizes the biosynthetic pathway of carotenoids and progresses in metabolic engineering of various microorganisms for carotenoid production. The advances in synthetic pathway and systems biology lead to many versatile engineering tools available to manipulate microorganisms. In this context, challenges and possible directions are also discussed to provide an insight of microbial engineering for improved production of carotenoids in the future.