Metabolomic Analysis of Carotenoids Biosynthesis by Sphingopyxis sp. USTB-05.

Carotenoids belonging to the class of tetraterpenoids have extensive applications in medicine, food, nutrition, cosmetics, and feed. Among them, lutein and zeaxanthin can prevent macular degeneration in the elderly, which is very important for protecting vision. Here, we introduce the first metabolomic analysis of Sphingopyxis sp. USTB-05, aiming to shed light on the biosynthesis of carotenoids. Sphingopyxis sp. USTB-05 has the complete methylerythritol 4-phosphate (MEP) pathway and carotenoid biosynthesis pathway, especially involved in the bioconversion of zeaxanthin, violaxanthin, and astaxanthin. Metabolomic profiling identified seven carotenes and six xanthophylls synthesized by Sphingopyxis sp. USTB-05. Zeaxanthin, in particular, was found to be the most abundant, with a content of 37.1 µg/g dry cells. Collectively, the results presented herein greatly enhance our understanding of Sphingopyxis sp. USTB-05 in carotenoids biosynthesis, and thus further accelerate its fundamental molecular investigations and biotechnological applications.