Exploring the Influence Mechanism of Low/High Temperatures on Carotenoid Production in <i>Sporobolomyces pararoseus</i>: Insights From Physiological and Transcriptomic Analyses

Carotenoids, a class of lipid-soluble isoprenoid pigments, play essential roles in determining coloration and enhancing nutritional value across various food products. Sporobolomyces pararoseus has emerged as a promising microbial platform for industrial-scale biosynthesis of high-value carotenoids, particularly β-carotene, torulene, and torularhodin. The study evaluated the specific impacts of low and high temperatures on carotenoid production in S. pararoseus. Quantitative analysis demonstrated a statistically significant reduction in total carotenoid content across temperature treatments, with values decreasing from 1347.03 μg/gdw under optimal conditions (25°C) to 180.77 μg/gdw at low temperature (12°C) and 1100.13 μg/gdw at high temperature (33°C), representing 86.6% and 18.3% reductions, respectively. The observed reduction in total carotenoid content can be predominantly ascribed to the downregulation of key enzymatic pathways involved in both terpenoid and carotenoid biosynthesis. Conversely, torularhodin production and its relative proportion within the total carotenoid profile were significantly increased under high-temperature conditions. The increase in torularhodin levels may represent an emergency antioxidant response designed to counteract the heightened oxidative stress induced by high temperature. These findings deepen our understanding of how cultural temperatures influence carotenoid levels in S. pararoseus and offer valuable molecular insights for further enhancing its carotenoid synthesis through genetic modifications.