Genetic manipulation for carotenoid production in microalgae an overview

Carotenoids are the most diverse pigments found in plants and animals. Carotenoids of various hues such as orange, red, and yellow are abundant in fruits and flowers. Also, they are responsible for the colors seen in some birds and fish. These pigments also offer significant health advantages, such as antioxidant and anti-inflammatory properties, and they have a wide range of applications in the food, cosmetics, and pharmaceutical industries. Carotenoids are key phytocomponents in plants and microalgae for light harvesting, energy transfer during photosynthesis, and protection from photo-oxidative damage. Microalgae are a diverse group of photosynthetic organisms that provide the foundation of the food chain in aquatic habitats. Dunaleilla salina, Haematococcus pluvialis, Chlorella vulgaris, Chlorella pyrenoidosa, and Chlorella zofingiensis are the richest sources for β-carotene, astaxanthin, lycopene, lutein, and zeaxanthin. Microalgae provide renewable supplies for increasing carotenoids because of their perfect host environment, simplicity of culture, and rapid growth rate. Genetic manipulation tools such as overexpression and gene knockout techniques are emerging approaches to study the carotenoid metabolic pathway and reveal information about the critical enzymes in the pathway. In this review, we discussed recent developments in genetic manipulation to overproduce carotenoids. Recent genetic manipulation tools are potential options for increasing productivity in microalgae. These approaches will enhance the production of carotenoids in commercial microalgal species for industrial applications.