Synchronized nutrient stress conditions trigger the diversion of CDP-DG pathway of phospholipids synthesis towards de novo TAG synthesis in oleaginous yeast escalating biodiesel production

In this study oleaginous yeast, Rhodosporidium kratochvilovae HIMPA1 grown in glucose synthetic medium containing different nitrogen (1 g/l and 0.1 g/l) and phosphorus (0.05 g/l and 0.1 g/l) limited conditions. Among various N and P-limited conditions, the highest lipid content (60.34± 0.69%) obtained under synchronized limitation of N and P (0.1 g/l N and 0.05 g/l P). Live fluorescent cell imaging of yeast cells after BODIPY505-515 nm staining endorses the results of triacylglycerol (TAG) accumulation in lipid droplets. The cells grown in synchronized limitation of N and P exhibited boosted cell size (6.76 ± 0.39 μm) and lipid droplet size (5.62 ± 0.28 μm). Under synchronized limitation of N and P, supersized irregular shaped lipid droplets (LD) coalesced to form big lobules in the cellular compartment of oleaginous yeast having 87.14% enhanced TAG accumulation as depicted by TLC. Synchronized nutrient limitation diverts the CDP-DG pathway of phospholipids synthesis towards de novo TAG synthesis. The maximum increment of oleic acid (C18:1) was reported in synchronized limitation of N and P that improve the biodiesel properties like oxidative stability, viscosity, cetane number and cold filter plugging point.