Maximizing lipid accumulation in Tetradesmus obliquus under heavy metal stress for sustainable biodiesel innovation.

This study investigates the potential of Tetradesmus obliquus for lipid accumulation under heavy metal stress and evaluates it's aviability for biodiesel production. We surveyed how different concentrations of heavy metals, including manganese (Mn), cobalt (Co), and zinc (Zn), influence the carbohydrate & protein, lipid yield, and fatty acid profiles of T. obliquus cultures. Our results demonstrated that while lipid content increased under heavy metal stress, the extent of accumulation was highly dependent on metal type and concentration. Notably, the algal culture treated with 0.04 mM Co²⁺ showed the highest lipid accumulation. Treatment with 0.3 mM Zn²⁺ resulted in the highest proportion of saturated fatty acids (SFA). The Relative Enrichment Efficiency Coefficient (REEC) analysis demonstrated that 0.04 mM and 0.07 mM Co²⁺ led to the highest lipid and carbohydrate content stimulation. Additionally, GC-MS analysis revealed increased monounsaturated fatty acids (MUFA) under several metal stress conditions. The study demonstrated that exposure to specific concentrations of heavy metals can significantly enhance lipid accumulation and alter the fatty acid profiles of T. obliquus, which are crucial for improving biodiesel quality. The implications of these findings suggest that heavy metal-induced stress could be a feasible approach to enhancing lipid accumulation for sustainable biodiesel production, and T.obliquus is a promising candidate for future biodiesel production.