Stress-induced astaxanthin biosynthesis in Phaffia rhodozyma: Bridging mechanistic understanding to industrial...

Phaffia rhodozyma presents a sustainable alternative to synthetic astaxanthin production, however, its industrial scalability is limited by low yields and unresolved mechanistic ambiguities. This review systematically examines the characteristics of P. rhodozyma, its astaxanthin biosynthetic pathway, and the current advancements of strain development. It critically evaluates existing strategies for enhancing astaxanthin production, with particular emphasis on the application of stress factors during fermentation processes. Furthermore, the mechanisms underlying stress-induced astaxanthin accumulation are comprehensively elucidated, encompassing oxidative stress-driven astaxanthin synthesis, enhancing precursor supply through regulation of central carbon metabolic pathways, as well as competitive pathways, and esterification-mediated alleviation of feedback inhibition. The stress-induced synergistic regulation of multiple mechanisms is systematically analyzed, along with a rational framework for the selection and application of stress factors. This in-depth analysis provides actionable insights to facilitate the transition from laboratory-scale studies to industrial applications of P. rhodozyma.