Revealing mechanisms of algal astaxanthin production and bioengineering potential using multiomics

The ketocarotenoid astaxanthin (Ax) harvested from microalgae has high industrial potential and is a promising compound for improving human health. Several algal species accumulate astaxanthin as an acclimation response to environmental conditions such as high light, nitrogen deprivation, and glucose, but certain bottlenecks make biologically derived astaxanthin not cost-competitive with synthetic astaxanthin. In this review, we provide an overview on the evolution and distribution of astaxanthin accumulation in algae; regulation of carotenoid pathway for astaxanthin accumulation; and algal astaxanthin biosynthesis, packaging, and storage. We focus on the two most-studied, astaxanthin-producing green algae Haematococcus pluvialis and Chromochloris zofingiensis, use multiomics datasets to offer new insights, and present three strategies for increasing microalgal astaxanthin accumulation. A multiomics understanding of the system-wide transformation of a cell accumulating astaxanthin uncovers bioengineering prospects for increasing astaxanthin productivity to improve feasibility of biologically derived astaxanthin for industry and in particular for human health.